One company that is offering stainless disc brakes is King Trailers Inc. in Marysville WA, 360-651-7887 . They are using torsion springs, replaceable stainless spindles, stainless rotors & sealed boots  over the disc piston (automotive disc unit's boots are merely a dust cover and do not keep water out).

Inspecting by Rotating Wheel ;  Some say that they simply do a yearly jack the trailer up, and rotate the wheel to tell if the bearings are good.  Yes, this is a possibility, but how much experience do you have doing this, how delicate is your feeling and can you hear as well as you once did to be able to identify, or even know what to listen for as to a bad bearing sound?  

One thing that has been found, is that if you CAN hear the bearings, they almost always are dry AND BAD.  A suggestion is to try this method before you remove the wheel and hub.  From what you hear and feel you may be able to come to some educated conclusions of what you find after you disassemble the hub.

I have to admit that I have pulled the bearing protectors, looked at the grease and reinstalled the protectors if everything looked OK.  However I suggest that you do not get into a habit of being lazy every spring, as you will get bit in the butt before too long.  BEEN THERE --- DONE THAT.

Also if your trailer has brakes, when rotating the wheel by hand, you may be also hearing the brake shoes dragging on rust on the inside of the brake drums, that has accumulated during a period of non use, as when the boat is sitting all winter.

Removal of the Wheel & Hub ;  For those of you who may be doing this the first time, there are some safety issues that you need to be aware of.  (1)  Loosen the lug nuts while the trailer tires are still setting on the ground.  (2) Jack the trailer axle up enough to give ground clearance.  Block the opposite tire, both front and rear so that the trailer does not move or possibly fall and pin you, or part of you, under it.  (3) Remove the lug nuts and wheel with tire attached, place the nuts, (or bolts) in a secure location so you will have them when you reassemble.

For the greased bearings, which will usually have some sort of a "Bearing Buddy" or grease retainer system, these caps can be either metal or plastic.  Using a mallet, tap one side of the outer end, rotate the hub and do it again until the cap is loose enough to be removed outward.

For the oil bath hub, rotate the hub so that the small 1/8" pipe plug is up.  Remove this plug.  Place a container under the hub to catch the oil, rotate the hub so the oil drains out.  The plastic end cap will have to be removed.   It is usually screwed into the hub, but could be pressed in depending on brand and uses a thin O-Ring inside as a seal. 

Once the cap is off, remove the cotter pin that goes thru the axle castle nut.  Unscrew the nut and remove it, also placing it in a safe place.  Then there will be a large washer under this nut, remove it also.  The hub should now be able to be slid out off the axle.  Be sure to catch the washer and bearings.  Keep them in sequence as you remove them so you can replace them right. 

Replace in reverse order and as describe farther down in this article.

Inspect What You Have, Clean, Replace ;  The suggestion is then to do your homework before all of this potential situation can happen.  To take the dust caps or bearing protectors off, use a mallet and tap on one of the outer edges, rotate slightly and tap again.  Keep this up until the protector has moved out enough for it to be taken off.  Remove the cotter pin and nut from the axle's outer end.  Remove the spindle nut.  Keep the greased internal parts clean until you decide whether they need replaced or not.

Pull your hub off and the outer bearing will fall out as it was held in by the washer and nut.  If the hub does not want to come off, the usual problem is that the drum has rusted enough on the inside that it is now dragging on the brake lining.  You might have to pry, tap on one side and then the other slowly moving it outward.  Once you get the hub off, the outer bearing should be able to be taken off easily, you can make a good judgment call if the bearings are OK or not. 

If the grease is light enough to flow all around the spindle and bearings, when you take the hub off, if the whole inside is solidly filled with grease, and is NOT a milky color.  You can probably just reinstall the hub.  However if is has a milky/muddy color, this is indicative of water being in there at one time.  Water, especially salt water, is not conducive to good bearing life.  If the grease is a heavy type, there may be water in there but the color has not changed because the grease is so thick it does not allow the water do anything other than find holes in the grease.

If you need to get to the inner bearing and seal, use a hammer handle or large piece of wood large enough to just go through the outer race or cone as it is officially known, that is still retained in the hub by the inner seal in the hub.  Place this wood inside the hub against the inner bearing and tap the end to force the inner bearing and seal out thre back /rear side.  If you use a large steel punch instead, with all the grease in there, and you can't see, you may just drive the punch between the bearing and roller cage, possibly ruining it, (I've done this).  

While you have the bearings off, clean them up with solvent, inspect them for rust or any roughness.  If there is any discoloration or roughness in the bearings or races, REPLACE THEM.  Also, replace the seals at the same time.  A suggestion here is to write down the old bearing numbers for future reference.  Start a file of your trailer specifications and keep this info on your boat or towing vehicle.  Make notes as to bearing and seal numbers.  Replace any parts that may be even the least bit rough or rusty.  Buy spare parts and keep them with the boat.

When inspecting the bearings, look at the rollers carefully for any signs of rust/pitting  If there is any at all, replace both the bearing and the race.  You may see slight rusting on a roller and think this is not that bad, but if you do see any pitting, think about it, the roller is touching the race in a minuscule location, so what you see on the roller will be magnified multiple times on the race.  You can easily see the roller, but will have to look carefully and clean the race well to be able to see anything on the inside there.    

You should replace both the bearing and the matching race, never put a new bearing in an old race except in an emergency situation.  The races will have to be driven out with a long heavy punch and hammer from the opposite side of the hub.  Also it might be wise to shy away from any "made  in China" brand bearings, and stay with a more well known brand. 

Brake Drums ;   If yours look like the ones above with a lots of rust, you will need to clean them up.   This could involve only the use of some course sandpaper, or a angle head grinder fitted with a cupped wire wheel.   For those of you who may have access to a larger metal lathe, mounting it in the chuck and running at a slow speed, using a course emery cloth does wonders.   When you do this, if the bearings are OK, you do not plan on removing them, you will have to stuff paper towels inside the spindle/bearing holes to protect them from being contaminated by your rust removal.


Brake Lining ;  Inspect the brake shoe lining while you have it apart.  The lining will not be worn down only by the amount of stopping you do, but if you launch in salt water, the drum will get rust on the inside of it no matter what you do.  This is the area that the shoes make contact with.  The rust is more abrasive and it wears the lining down way more than just braking will.  Even though you flush the backing plates and brakes out with fresh water after use, the drums will rust.  

Take a look on the inside surface of your tires, if you are seeing a redish-brown rusty color on the tires and on the frame behind your axle, it more than likely is rust coming off the brake drum.  If you last launched in salt water, even flushed the backing plate out, the drum surface will begin to rust.  When you later tow the trailer and apply the brakes, the brake shoes will scrub some rust off the drum, this is what you are seeing.

It is my suggestion that if you are a seasonal user that after your last fall trip, that you take off the drums and wire brush or sand the inside drum down and lightly oil it with WD40 or a similar product.  This may prevent major winter rusting, and extend the life of your brake lining.  When you reinstall the drum, you should also check and possibly then readjust the brakes.

Carry Spare Parts ;     OK, you have decided to replace you trailer bearings and seals.  The bearings can be purchased at an automotive parts house, but be aware that they usually have about 3 different price levels.  Sure your brother-in-law can get a discount, but many times the marine dealer can give you a better price because they are buying through the boating industry and it is suspected that more bearings are sold each year through them than the same bearings thru a automotive dealer.  One customer reported he paid $44 (reg. $63) for a set of bearings at the automotive supply house, that he could have gotten the same from Boaters World for $13.

Now don’t stop at just replacing the bearings and seals.  Again the freeway or secondary highway is a lonely place for the broke down fisherman.  The suggestion is to also purchase a new spare hub assembly.  Put it in your towing vehicle or boat in a waterproof bag, keep it there as an insurance policy.  It might just be that you won’t need it, since you are now more enlightened as to trailer maintenance, but what about that other fisherman who has not had the foresight to do what you just did.  Just maybe your part will fit his trailer, you now have a new friend for life that may just share his favorite fishing secrets.

On my last small trailer wheel bearing repair, only one of the four bearing/races were good enough to reuse, but I bought all four new and saved the other and the seal as a spare.  I then greased them and Vacuum Packed it so it would not rust.  Maybe I won't need it, but possibly I can help another boater.

Another thing to carry would be a plastic cap (protector) that can be fitted over the hub in case you loose a bearing saver.  I lost one on my trailer recently and I suspect one of my friends, not knowing, may have used the Bearing Buddy as a step to help climb into the boat while on the trailer.  This may have moved it mostly out of the hub and after a couple of launches, it must be somewhere along the roadside.  Here I am an hour and a half drive from home, launching in saltwater before I notice the bearing protector missing.  Upon reaching the RV lot, I finally found that if I cut off part of a used soda can it would slide over the hub's spindle area.  I then duct taped the can to the hub making sure it did not rub on the spindle's cotter pin.  Worked until I got home, where I pulled the hub apart, checked the bearing for salt corrosion, which the races had slight discoloring but nothing to give permanent damage after replacing the grease.

Now remember all those questions asked before?  Here are some things you will find when you try to find replacement parts.

Replacement hubs for non brake models are a lot easier to find.  Many can be purchased in the larger marine supply or mail order stores.  They are usually identified by the bolt pattern and shaft size.  They usually sell for about from $30 to $45 each, depending on the size, and this also includes bearings and a seal.  By themselves, most bearing and seal sets sell from $12 to $15 range.


It would a good idea to find your trailer's proper size and carry a spare hub assembly.  You also already have a spare tire/wheel, RIGHT ?   It might be a good idea to also carry a few spare lug nuts or bolts (note some hubs use bolts, while others have studs which will require the use of nuts).


West Marine's catalog lists 3 basic non brake hub / spindle sizes. 
       (1) a 4 hole, either stud or hole 4" bolt circle dia.,  with a 1'" spindle dia.
       (2) a 5 stud, 4 1/2" bolt circle dia. with a 1 1/16" spindle dia. 
       (3) a 5 stud, 4 1/2" bolt circle dia. with a dual spindle dia. of 1 3/8" & 1 1/16" 

Finding brake type parts are where the fun really starts.  As most of you are aware, anything associated to “BOAT” means the price is usually doubled.  So to save money, and since they are more readily available, you can try an automotive parts store.  They probably will be able to get bearings for you if you have the old ones, or what is left of them, but they may not have any cross-reference charts to boat trailers.  As mentioned before, automotive seals should only be used as an emergency.  The automotive stores will not likely be able to find brake shoes for you, as trailer shoes are different than most cars or light trucks.

You will probably have your best luck for trailer brake parts at an RV parts store.  These boat trailer brake parts are usually the same as many RV axles use.  Now it appears that not all of these stores may not carry much of this type of parts in inventory, as they can order it and usually have it in a couple of days.  So do not really expect to walk back out 15 minutes later with what you need.  Also, some parts counterpersons seem to leave the impression that they think that you are “their pigeon”, and they are not too willing to share any information with you as to what they have decided you need if they don't have them in stock.  It is doubtful that their computer lists anything more than just a description, size, part number and price.  This makes it hard if you want go elsewhere armed with any knowledge at all, to try and find what they do not have.

Some Trailer Manufacturers Use Non-Standard Seals ;  I recently  was approached by a neighbor who was farsighted enough to want to replace his wheel bearings after only 22 years.   This was on a single axle Shorelander trailer.  He had gotten new bearings from an automotive parts store, but the seal was also automotive type and I suggested he go to a regular boat trailer shop for the proper one.    He is glad he did, as the original marine seal "made in Korea" has no current replacement and is not available anymore. 

The counterperson/repairman at the trailer repair business, being very knowledgeable, told him what brand of trailer he had just by looking at the original seal from his past experience.  He was told that if he ever had bearing/seal problems on the road, that he would never be able to do a proper roadside repair.  One solution would be to get a new marine seal of the right shaft size, but larger outside diameter and have a machine shop turn the hub oversize to match a currently available marine seal.  Other than that the solution was to remove the axle, have new spindles welded in place that would accept currently available spindles and seals, OR buy a whole new axle.

So You Have Driven Too Far & Ruined the Spindle ;   If in this case, you go to a marine trailer dealer, they may want to sell you a new axle if the trailer is old enough to not have replaceable spindles (which most will fit in this category).  They may tell you that a new spindle can not be fabricated and welded on without the use of laser guided alignment equipment.  My response is Bull Shit.   Sure it needs to be close and even maybe have a little toe in, but many trailers have been made the old way in the past.  Don't cut a farm type mechanic shop short, as they see this type of stuff all the time.

In the photo below, the owner neglected to check his wheel bearings.  The roller bearings are completely gone and in all probability the axle is ruined on this one.

It sometimes becomes painfully evident that you should have inspected your trailer axles bearings and seals more often.  Sure, you checked or replaced them a year or so ago, or you intended to grease them when you got home, but to be broke down with a burned up set of bearings then damaged spindle along the highway and a long way from help can be frustrating and possibly disastrous.

One well known boat/motor dealer tells of a boater who's trailer bearings were bad and  the driver was intent on "Getting There" and did not noticing anything wrong.  He was towing a large boat down the freeway in the middle of a large city, at legal speed, when the wheel fell off, it threw the boat off the trailer, totaling out the boat.  Also most likely there was more than a slight traffic jam. 

Not Me ;   You say it won’t happen to me.  Well, guess again, have you ever stepped on and broken a fishing rod tip?  Have you ever done a dumb thing on the launching ramp?  How about forgetting your bait box or left your tackle box sitting at home, or worse on the dock?  Have you ever lost a good fish at the net because you got didn't get around to replacing the net bag?   How many of you have lost a fish because you neglected to replace a leader after landing a previous nice fish?  How about getting a downrigger wire around the prop?  Believe me, it can and does happen if you stay with this fishing/boating game long enough. 

Do you want to leave your boat and trailer at the mercy of anyone who happens along the highway while you go 50 miles or more for repair parts?  Which could take days if the parts need to be ordered.  Do you leave the wife or partner stranded along the road on a rainy morning or hot afternoon with your boat, not knowing when you will return?  If you have a cell phone, who do you call that can help you on a Sunday evening, when you are 200 miles from home?  Do you even know what type of spindle/brake parts that you may need if you find someone who may be willing to help?

Hopefully this article may help somewhat, if nothing more than a wake-up call, by trying to cover trailer maintenance, repairs and other useful information..

Most boat trailer manufacturers do not make their own spindle/brake parts.  They buy existing units or assemblies from major accessory manufacturers.   This may help you in a way, since it expands the sources that you can get repairs at if you know what you need and some idea of where to look.    But this may also be bad if the manufacturer used non-standard parts. 

What Do I Have? ;  Now comes the fun part.  There are MANY makes and models of boat trailers.  If you are at home and have the old parts, you could even have some trouble when you drag in the old parts to a store to ordering  new replacement parts.  But on the road is something totally different.  Even if you can find a marine / RV dealer that is open, do you know the make, model and weight capacity of your trailer?  Do they carry the same make trailer as yours is, if not, will they interchange?   What size, as far as poundage is your axle?  Does your axle have 4 or 5 lug bolts, or are they studs?  Do you have brakes or not?  If you do have brakes, are they surge type?  are they disc or drum type? What size drums are they, 10” or 12”?  Are they “Standard” or  “Free Backing” type?  Do you need RH or LH wheel cylinders or shoes?  Are the backing plates painted or galvanized?

Most of the above questions need to be answered before most parts houses can identify your trailer / spindle / axle / hub / brakes.   Otherwise, you look just like all the other week-end know-it-all boaters that pull stupid stunts.  Some of the dealers/counterpersons can make an educated guess, after some questioning.  But you might get rather irritated at yourself if YOU guessed and gave them the wrong information and they then gave you the wrong parts needed for your trailer 50 miles back down the road.   

One other thing,    
Before We Go Any Farther ;  No matter how prepared you are, there is one thing that can and does happen oftener than you imagine.  That is when you remove the lug nuts on either your towing vehicle or boat trailer and the wheel is rusted to the hub.  This is common if you live or drive in an area where DOT salts, or uses deicer on the roads.  This also could be for those of you who launch and retrieve your boat a lot in salt water.  The steel wheels rust to the brake drum or spindle hub.  Aluminum wheels seem to not be as effected as much by this disease.

A pre season maintenance where you remove the wheels, inspect and possibly clean this area and lubricate with anti-seize or even chassis grease may help prevent this frustrating situation would be a good idea.  This would also be a good time to rotate your trailer tires.  You may have never thought about that, but you are recommended to do it regularly on vehicle tires to extend the tread life, why not trailer tires also?

OK, now that you know, but do get caught in this situation, here is what Les Schwab does.  They have a long handled 4# sledge hammer that they use to reach in and hit the TIRE on the inside.  However it is suggested that you replace some of the lug nuts first (BUT LOOSE) so when it pops off that there is a possibility you also may knock the jack loose, as you do not want the axle laying on the road.  Since most of us do not carry this type of removal took with us, remove your trailer hitch and ball, using it to beat the wheel off.

If that does not work, replace the nuts but only tighten them about 1/2 way and SLOWLY drive a short distance.  If it is on the front of the towing vehicle try to crank the steering wheel right/left which also may help break the rusted bond loose.   

Wheel Bearings ; No matter what brand of trailer or what type of axle/spindle system it uses they all will have basically the same type of wheel bearings.  The key to bearing longevity is LUBRICATION.  The older systems utilized grease, the type being mentioned below.  The newer units utilize a heavy oil, (oil bath system) which gives better lubrication.  These newer hubs will have a clear plastic cover which allows you to visually see the internal oil level.

Bearing Protector System ;   If you have someone going with you on your boat, it may be best to inform them that IF CLIMBING into the boat while it is on the trailer, the bearing protectors ARE NOT a step.  If they will step on one, it will upset the protector in the hub, as it is merely a snug tapped fit into the hub.  Once the protector is not running concentrically, the high RPM of the wheel turning will throw this protector off.  And if you do not catch it before you launch in saltwater, and you are on the first day of a week's vacation, you may have to get inventive.

The term bearing protectors, refers to a method of retaining the grease within the hub and lubricating the internal hub and bearings, while at the same time allowing for the owner to know how well the system is functioning as compared to just a metal cover hiding everything.  The most popular for trailers up until about the year 2002 is the spring loaded dust cap device with a grease Zerk fitting in the piston. 

Another thing to do is to smear some wheel bearing grease on and in the brake line bleeder valve hole on the wheel cylinder after you have bled the brakes.   Or get one of the rubber caps designed for this.  What this does is keeps saltwater from leaking back in thru this bleed off hole, collecting behind the valve seal, creating a rusted in bleeder valve next time you try to adjust the brakes or need to make repairs.

If you even use the trailer in salt water occasionally, no matter how much you flush it, the internal brake parts, (springs, hold downs, adjustment units etc. )  WILL become RUSTY even to the point that they will become weak or deteriorate to the point where they are not reusable.  

You can usually salvage the rusty shoes and drum, but the parts that over time seem to need replacing are the springs.  If you are not in an area where you can readily obtain original replacement internal parts for these brakes, the usual automotive springs can be substituted.  They however are not made of stainless steel like the originals, but may be able to get you by if you preserve them.   I have found that Car Quest brake axle kit #H7068 is a universal kit that you can pick thru and find springs that are close enough that will function.

If you have to buy a new backing plate assembly do not even consider a painted one UNLESS you are on the road and broke down.  It will be cheaper as it is designed for regular automotive type RV trailers, NOT boat trailers.

Adjusting the Brakes ;  Re-install your tires and rims on the trailer at this time and find the brake adjusting slot at the bottom rear of each brake backing plate  There  will usually be two slots on the back lower side of the backing plates.  These backing plates are universal and can be used for either RH or LH units.  It might be advisable that while you are replacing the parts and before you put the hub/drum on the spindle to locate the adjusting slot for each wheel.  It however is usually the rear slot for the RH side and the front slot for the LH side on boat trailers. 

Remove the small oblong rubber plug if applicable, from the brake adjusting slot and insert a brake adjusting tool or screw driver in the slot and locate the star with the tool in one of the notches.  Rotate the star nut on the brake adjusting screw inside the brake unit by moving the tool up or down while the inner end is engaged in the star nut, moving the nut down.  Usually the threads are RH so the tool needs to be inserted with the handle end down, by raising the tool up, you extend the threaded shaft tightening the brakes.  Drop the tool back and engage it again, and again. 

If you go the wrong way it will just bottom out inside the adjuster and you can not move it any farther.   Change your motion direction and rotate the start nut the other way until you can feel and hear the linings start to drag as you rotate the drum.  Continue to adjust the star nut with the tool and rotate the wheel until you cannot turn the tire and rim by hand so you can tell when you are getting close.  As you turn the wheel now you should hear a slight dragging of the shoes the drum.  Go farther to where it tightens up and you can not rotate the wheel.  This will align the brake shoes and now you can back it off, otherwise you may have one wheel set differently than the others.  In backing it off, I mean,  reverse your tool and back it off about four or five clicks on the star adjusting nut, or to where it has minimal drag so the brakes do not get hot when you are towing.  This will have your brakes adjusted to their optimum set point.

Bleeding The Brakes ;   If you did not remove the wheel cylinder, or allow the piston to come out, allowing brake fluid to escape, you will probably not need to go through this exercise. 

Otherwise, you are now ready to bleed the brakes.  With the method described below one person can do this job.First fill the surge brake master cylinder reservoir with automotive DOT type 3 brake fluid.

If you have had more than one wheel apart for repairs, go to the brake wheel cylinder farthest from the master cylinder in the brake line tubing sequence first.

Obtain a piece of 1/4" clear plastic hose about two feet long, place a 3/8" box end wrench on the bleeder fitting and then push the piece of hose onto the bleed valve barb.  Now you will need a clear container (I like to use a cleaned clear bottled water bottle so I can see what is happening) to use as your fluid receiving container.  Set the fluid receiving container at some point higher the wheel cylinder.  

Now route the plastic hose from the bleed valve barb to the fluid receiving container.  NOTE:  The fluid receiving container must be above the wheel cylinder so that any bubbles trapped in the bleed hose will flow up away from the wheel cylinder, not back towards it, which would be the case if the fluid receiving container were lower than the wheel cylinder.  Pour about 1" of brake fluid in the container, enough so that the hose end is submerged, otherwise in your process, air will be sucked back into the system..

Open the barbed bleed valve on that wheel cylinder part of a turn, with a 3/8" box end wrench. 

Going to the surge brake master cylinder unit, you may find different methods of manually activating the master cylinder without actually backing the trailer up.  The simple method is to remove your ball hitch unit from the receiver of your towing vehicle and latch the ball into the hitch.  Now you can use the extension as a lever to pump the master cylinder.  One brand of surge unit will allow you to insert a large screw driver into the 1/2" dia. hole in the coupler under the nut on the pushrod which extends out the front of the brake coupler housing.  Be sure that you reposition the backup lock lever down to allow the master cylinder unit to operate.  

Remove the cap on the master cylinder reservoir and fill it.  With your "LEVER" in place, you can use a slow back and forth motion to apply levered pressure directly to the master cylinder pushrod.  The shock damper mechanism will still be in use, but it just takes a little more force to work your "lever".  You are now purging air from the brake line and wheel cylinder. CAUTION. It is not a good idea to look directly into the reservoir while pumping the push rod. The brake fluid may squirt up with considerable force during the first part of each pump stroke.  Brake fluid is something you don't want in the eye.  You can set the filler cap on top to control this squirt.

As you pump brake fluid into the system, you will begin to see it flow up the clear plastic tube to the fluid receiving container at the wheel. (CAUTION - Never let the main reservoir fall below 1/2 full during the bleeding process).  If the fluid gets too low and sucks air down into the piston of the master cylinder, you must start over and the new air just sucked in and all brake fluid already in the system will need to be purged out.  As you pump fluid thru the system, the bubbles you have been seeing in the tube or fluid receiving container will cease.  This indicates that you have completely filled the system with brake fluid.

Now, with the bleeder hose still on the bleed valve barb, and the hose end still in the fluid, close and tighten the bleed valve. Remove the hose and repeat this process by going to the next wheel that is next, in being the farthest from the master cylinder.  There is a small rubber boot that comes with the new wheel cylinders that covers these exposed bleeder valve barbs.  Be sure to place them back on the barb when finished to help keep water out of the barb.

Before moving to the next wheel, check and refill the master cylinder in the surge brake unit. 

Next, apply pressure to the push rod and hold hard pressure on the "lever" for five or ten seconds.  This will develop maximum hydraulic pressure on the system, and make it easy for you to see fluid if you have any leaks. After totally checking the system for leaks, you are now ready to adjust the brakes.

After completion of the bleeding process, refill the master cylinder reservoir and reinstall the reservoir fill cap and tighten.

Testing the Brakes ;   Now have a helper activate the surge brake master cylinder with the large screw driver, as you did when you were bleeding the brakes.  Vigorously spin the tire and wheel and then have him apply the screw driver pressure to the master cylinder push rod.  The wheel should come to an abrupt stop.  After the pressure on the master cylinder is released, the tire should rotate freely with only the slight drag of the shoe and drum noted.  Check both sides to confirm that they are operating equally, otherwise when you apply the brake pedal while in motion on the highway, the trailer could pull to one side.

Road Test ;   You have now completed the installation and are ready to road test your workmanship.  NOTE:  There is a mechanical time delay built into the surge system through a small shock absorber internally in the unit.  Your trailer brakes will be felt to engage about 1/2 second after you have applied brakes in the tow vehicle.  Depending on your trailer and the weight of the boat, you may not really feel the trailer's braking system taking a hold until the last 30' or so from a complete stop.


Converting Drum to Disc Type Brakes ;   For those of you who frequent salt water, get tired of replacing your brakes every couple of years, there is an answer.   Convert to Disc type.  These units are available from of marine dealers as replacement but are listed for each wheel, NOT per axle.   This means that if you have a tandem axle you will need to purchase 4 units at approximately $150 each.   Plus you MAY have to also purchase a new master cylinder / hitch / activator unit for another $160, or purchase a electrical backup lockout switch that locks the trailer brakes out so you can back your boat trailer.  This seems expensive, and for those of you who are not concerned about your equipment, you will not be reading this anyway.  For you others, replacing individual parts frequently gets expensive which also cuts into our fishing time.

Most of these disc units use caliper type brakes and rotor so common on automobiles now, but with a stainless rotor.  For a link to Tie Down Engineering Inc. , go to 

Seal Saver System ;    There is one thing that is worthwhile to consider installing also.  This is called a Spindle Seal Service kit, and is made by Bearing Buddy.  It is a thin stainless steel hollow cup with a hole the size of the spindle shaft on one end, and the other is just large enough to slip over the seal surface of the spindle.  There is a small neoprene O Ring that goes between the inner lip and the saver.  The inner bearing puts pressure against the saver and compresses the O Ring to keep water from coming in under the saver.  What this does is give the seal a better surface to seal against.  It being stainless, it will not rust or get pitted like the regular steel spindle, which can chew a new seal up.  Being thin, it however does increase the shaft dia., requiring Bearing Buddy's own special seal.  

What this was apparently designed for was, if you had bearing failure and the spindle got chewed up at the seal area, you could save the axle by simply adding this simple device.  However it this persons opinion that these units should also be installed as a preventative measure at the same time as new bearings and seals are installed, especially if your trailer is more than a few years old and you use it in salt water.

One thing about the design and or that the instructions don't mention is that I have found that the neoprene O Ring sometimes does not seal out water from coming in behind and under the saver sleeve.  It is my suggestion that at the time you install the sleeve, that you coat the spindle at the old seal and shoulder area with heavy chassis grease or a silicone gasket sealer.  Then when the spindle nut tightens the bearings against the shoulder, this grease will act as an added sealant.

Replacement seals for Bearing Buddy can be purchased direct from Bearing Buddy for $1.75 each, plus shipping  They will take orders by e-mail and credit card.

Non Brake Units ;  Small and medium size boat trailers designed for boats up to about 18' and up to 3000# are not required to have brakes.   Spare or replacement hubs and bearings for non brake models are a lot easier to find.   Many are even available at Wal-Mart.  They are usually identified by the spindle shaft size at the bearing, and depending on the spindle size, can use the same bearing, both inner and outer.   However I have found that some of these "wheel bearing/seal kits" may not have the proper size seal for ALL trailers using that size of bearing, so if buying a kit, be sure you are getting the right one for your trailer.


Drum or Disc Brakes ;  The bulk of the trailer brakes out there that have brakes will be drum brakes, activated by a surge unit that the trailer hitch is made a part of the hitch.  The surge brakes are applied by the forward momentum of the trailer, when you apply the brakes of the towing vehicle.  The trailer "surges" forward  activating the master cylinder in the surge unit.  The more the trailer pushes against the towing vehicle, the more the trailer brakes are applied.  

Disc (or caliper) brakes are starting to show on the larger type trailers.  These can be had with powder coated or stainless steel rotors.  The braking methods can be the same as surge drum brakes (most preferred if near salt water), or a electric unit,  activated automatically when the towing vehicle's brakes are applied.  The disc type surge require a lock-out solenoid which is activated by the towing vehicles backup lights.  This allows you to back the trailer.

Most any competent machine shop can copy the good other side's spindle, turn it on a lathe and weld it in place.  If they tack weld it, then install the bearings, hub and wheel, then with the tires on a concrete floor, they can rotate the axle, watching where the tire wobbles. Pounding on the spindle with a lead hammer in the right spot to align it, then rotate again.  When it is the same as the one on the other side, (toe in at the front matching the other side) then weld it securely in place. 

Loose Lug Nuts  ;    There is another issue to look at, loose lug nuts/bolts.  There is a happy medium on tightening lug nuts / bolts.  Tire shops will use a power impact wrench, which may be OK, but I have found that after I get home, I try to remove them, just to be sure that if I am stuck along the road somewhere, that my lug wrench is capable of doing so if /when needed.  If they are too tight, I loosen them and do it by hand with my 4 way lug wrench.   These combo wrenches have enough leverage that you can tighten the nuts/bolts, but rarely can you over tighten.  Better to do it at home than stranded along the road. 

In the photos below, you see the effect of loose lug nuts/bolts.  Here,  it appears that the bolts were loose, allowing the wheel to wear on the cast iron hub breaking the hub and subsequently tearing the hole center out of the wheel.  The RH photo shows the comparison between the old broken hub, broken in the middle between the bearings, and a new hub.  Some hubs use bolts, while others use studs, on this damaged one, it is hard to tell, but it appears to me that the old hub may have used bolts instead of studs, by the appearance of the worn out holes.   This one did not ruin the axle spindle.

Sorry, But You Have to Buy an Assembly ;    The hub/drum is no problem, as for about $55 to $65 through RV parts stores, you can order a complete painted brake drum assembly with the bearings and seal.  This price seems to be a rather good buy for what you get.   However it is suggested that you get the galvanized and not the painted ones.

If your brake shoes or lining are ruined, you will find that at most parts houses, you will probably have to buy a whole set of brake shoes (RH & LH) even though you only need one side.  These sell for up to $30 each side, so you have to pay $60 and get both, the one side you need, and will you ever use the other one?  The store may tell you that there are RH and LH shoes.  Yes, they go together on the trailer axle in that manner, or that is what the computer says, and maybe they are sold that way for liability reasons.  But on most versions, by simply reversing a bolt and a stud, you can change the shoe to fit the other side.

The other alternative, they will tell you is to buy a complete backing plate assembly, which includes the backing plate of course, plus a wheel cylinder, brake shoes with new lining, springs clips, etc. for about $75 +.  These also need to be ordered in either RH or LH versions.  It has been found that these can not be converted to the other side unless you purchase a new wheel cylinder.  All the other backing plate parts seem to interchange.

What if you only need a shoe return spring or a wheel cylinder rubber boot?  Sorry, but you have to buy the backing plate unit and get it all.

This "gotta buy what I have to sell you" may be the new generations thinking.  Maybe I am "old fashioned".  Why spend $75 for the whole thing when you only need $25 worth of parts.   Maybe in this modern day of computers, and a throw away society, in all probability, very few counterpersons really know what interchanges, or what fits what, all they know is just what the computer or micro-flitch number shows.  Or just maybe they feel that since you are in dire need of parts, and they are the "experts" you will have to take what is offered.  This is not to reflect against the local merchant, as they are just buying from the distributor.   Also in this method, the distributor has less inventory to stock this way.   Do you begin to detect a slight amount of bitterness here?

In my search for parts for my trailer here are some names of businesses other than your local boat trailer dealer, that I have found that can be helpful.  There may be other good ones out there that equally qualify, but these are the ones I turned up.

The one company I have found most knowledgeable, helpful and has individual parts is  Rapid Brake Service in Tumwater, WA. They have about all the parts needed in inventory to repair about any trailer and they will make up the hydraulic hoses as well.

Rapid Brake Service,  7160 Capitol Blvd SE, Tumwater, WA 98501,  (800) 368-5360                      
                       Very knowledgeable owners & countermen,  will supply individual brake parts, hubs, etc.
                       can reline shoes if replacements are not available.

South Side Brake & Clutch,  3612 S 54th St. Tacoma, WA 98409  (253) 473-1433 
                      Has good selection of bearings, seals, backing plate assemblies, hubs, drum assemblies.

Right Way Spring Co.,  2545 S Jefferson Ave,  Tacoma, WA 98402   (253) 272-4022
                      Has limited wheel parts, but is helpful & does have replacement springs

 Listed below is information derived from the adventure of trailer brake part chasing.


 EZ Loader single axle 2000# size trailer, 12" wheels, 5 hole (1996 version)

Wheel hub assembly including bearings & seal, (no brakes) 1 1/16" spindle dia. 5 hole @ $35
                Spindle bearing diameter are 1 1/16"   
                Seal spindle dia. 1.250",  seal OD 2.200"
                Bearing, Outer   (L44610, cone –L144649 roller bearing)
                Bearing, Inner    (L44610, cone –L144649 roller bearing)
                Bearing Buddy - # 1980 @ $18.20 pair,
                Bearing Buddy   Bra # 19B  @ $3.35 pair
                Spindle nut threads,  .802? OD x 20 tpi.  1 1/8” across hex
                Cotter pin    1/8" x 1 1/2"

Now another EZ Loader single axle 2000# size trailer, 12" wheels, 5 hole, (1980 version)
              This one uses the same bearings, but has a larger axle, using a different seal (1.375" ID with an OD of 2.000" & a width of .480" (National #710324)


1992 EZ Loader dual axle 4000# size trailer, 13" or 14" wheels

Wheel drum assembly including bearings & seal, Dexter #8-147, 10”x2.25” brake size  5 hole studs,  @ $57

 These are Free backing Brakes.  With a Uniservo  (1 push rod exiting the wheel cylinder) 1 1/8" wheel cylinder 

 Backing plate assembly is for a 3500# axle,  Tekonsha #40715,  10”x2.25” Dexter  @ $75  (specify RH/LH)

   a RH can be disassembled & reversed, if a LH wheel Cylinder is also used, to convert to a LH backing plate & or shoes

            Front Lining    .200 x 2.250,   #908-EE GA3 FA,   8 ¾” OAL

            Rear lining      .200 x 2.250,   #908-EE GA4 FA,   11 ¼” OAL

            Wheel cylinder bore size,  1.125”dia., wheel cyl. OD for boot 1.50”

            Wheel cylinder kit (complete wheel cylinder)  Fulton # 0700R or 0700L @$23.44 each

            If you need hoses, they are $18.95 each

            Spindle bearing diameters are 1 3/8” inner  & 1 1/16" outer

            Bearing, Inner    (Bravo - set B-A17)  (L68111, cone --L168149 roller bearing)      $6.58

            Bearing, Outer   (Bravo - set B-A4)   (L44610, cone –L144649 roller bearing)        $5.82

            Seal      EZ loader  #C1468 @ $3.50 – (marine - double lip seal)   2.566” OD x 1.800" x .600 

                         National    #442251 (automotive - only single lip seal)    2.566” OD x 1.800" x .410 

                         Bearing Buddy #Buddy  #BBI-6002, @ $2.75 each direct from Bearing Buddy
                                  WHEN USED WITH SEAL SAVER KIT,  2.566” OD x 1.8? x .590

            Bearing Buddy - # 1980 @ $18.20 pair,  

                         Bra # 19B  @ $3.35 pair

                         Spindle Seal System Kit #2 @ $12.92 pair, (includes seal savers & new seals)

            Spindle nut threads,  .802? OD x 20 tpi.  1 1/8” across hex

            Cotter pin    1/8" x 1 1/4"

            Surge brake unit.   Atwood # 82543, using replacement master cylinder #85841, at $54.95. however you will
                         have to purchase the front rubber boot & the cap separately for another $12.00.   

NOTE --  These prices were about the year 2000          



Suspension Systems ;  All commercial boat trailers will have some sort of a suspension system from the frame to the axles.  This could be a coil spring which would require bracing rods from about the mid part of the frame in some manner.  The other would be flat springs running lengthwise with the trailer.  These could have anywhere from a single to multiple leafs depending on the weight the trailer was designed to carry.

A problem with leaf springs, is that the springs can not be galvanized for corrosion protection because of the heat treating for proper tension, (or so says the manufacturers).  Now if the trailer has been exposed to salt water in any degree, the spring will start to rust, once that starts, it is hard to stop it.  The best I have found is to sand blast the rust off and use a product put out by CRC that is called Heavy Duty Corrosion Inhibitor.  This comes in a spray can and leaves a golden colored non hardening covering.

Next comes along Torsion Suspension.  The common type is usually the axle hub behind the spindle is made square.  The main axle itself is also square, but larger.  Rubber inserts are placed between each square edge of the spindle stub and between the axle inner square corners.  Now don't ask me how they get this together and make it stay there.  This makes a for a simple suspension system in that there are no external springs to rust or rattle while going down the road along with way less maintenance involved. 

Trailer Fender Info ;   Trailer fenders need to also be checked for bolts becoming loose.  A fender coming loose on the freeway could contribute to a bad tire problem under the wrong conditions.  Then if the trailer is used in saltwater rust can become a problem like the photos above.  Fenders are there for a reason, which is usually not for a step to climb into the boat with.   Most trailer fenders are made of galvanized steel.  However EZ Loader in 2005 started making injected molded plastic fenders.  I have owned both these steel fendered and plastic trailers.  The plastic have benefits that outweigh the steel ones in my mind.

Useful Tricks ;   

(1) One trick when backing a trailer, put your hand on the bottom of the steering wheel and use your mirrors.  Then all you have to do is move your hand in the direction you want the trailer to go.  Practice this in the driveway or an empty bank parking lot on a Sunday morning a few times and you'll get the hang of it.   It may be hard to see correctly AND compensate if you have the newer mirrors that the RH one says things are closer than they appear.   Here you will see the LH side in proper dimension, but the RH will be out of proportion.  Some boaters will get a standard mirror made and replace this RH lens.

(2)  On average boat ramps, a good rule of thumb is to back the trailer into the water until the front of the fender is at water level.  On extremely flat ramps you usually need to back in further; but on steeper ramps, not so far.   Keep in mind also that the type of boat and or trailer could make a big difference here where you may have to go deeper. 

(3) Carry  a few  2" X 6" boards about 12" long to be used for blocking under or above a jack if you need to jack up the trailer along the road.   This is a lot easier than trying to find rocks in the ditch large and flat enough or a rotten fence post.

(4) Occasionally you may have lug nuts seize on the studs and then the studs would turn in the hub when you try to remove the nut, making it impossible to get the wheel off.  You will have had to remove the entire wheel and hub assembly and drill through the backside of the stud and push it through the hub to remove it.  If this happens on the road, you will not be able to do your own repair on the spot.  You might therefore try using a minimal amount of anti-seize compound on the stud threads each time you work on a wheel/tire.  And check the lug nuts occasionally, but loosen them to be sure they will come off when you need to do so, and then them retighten again.

(5) One thing you can do to help if you have a tandem trailer and loose a bearing or have a flat and need to limp nearby for repairs, is to use an old travel trailer trick.  That is to carry a  short  2x4, 4" or so long with a hole drilled through each end.  In use, if say the rear tire went flat, jack up this axle.  If the trailer has the normal pivoting "walking arm" that is the anchor for the rear of the front spring and the anchor for the front of the rear spring is what you need to concentrate on.  This arm is normally about level and equalizes both springs. With the damaged or rear axle jacked up this arm will tip down in front because you have moved the load.  Use the 2x4 block and wedge it above the front of this arm and under the frame.  Run a wire through the holes to keep it from jiggling out.   Now let the jack down and you will have transferred a majority of the weight to the remaining or front or rear tire.  I would not go far with this system, and check the other tire often, but it may just get you off a freeway.

(6) Another thing that may save the day is to beforehand, purchase a couple of Edelmann # 120300 or Weatherhead #131X3 fittings.  Or secure a new flared brake line tubing nuts of the proper size to fit your unit.   Make up a short piece of flared tubing to fit this nut.  Install this tubing on the nut and bend or flatten the outer end.  Solder or weld the outer bent over end so that it will not leak.  You have now just made a brake line plug.  The Edelmann is itself a threaded flared plug.  If you get in a situation on the road, that you have to move the trailer, but you find that there is something broken or damaged inside the drum unit and you are loosing, or will loose brake fluid.   Disconnect the brake line from that particular wheel at the junction block on the axle.  Take one of these plugs and screw it into the junction block where you just removed the tubing.  What this will allow you to do, is move the trailer and possibly still have some trailer brakes on the other wheels.

(7) There is one more thing that may well help extend the life of your brakes.  It is a fresh water wash flush system.  West Marine and Boater's World list these kits for about $40.  This unit has a garden hose fitting attached to one end of plastic tubing, the other end goes into a tee and then into the backing plate of each wheel.  When you get the boat out of salt water, you can use fresh water to flush the salt out of the brakes inside the wheel unit.  This needs to be done before you drive away from the prep area & before the salt has a chance to dry.   Many launches do not have a flushing hose. 

One simple method of personally accomplishing this flushing, is to carry a 5 gallon plastic bucket full of fresh water and adapt a small bilge or live well pump to it for this purpose.  Power for the pump can come from your downrigger plug ins, or off the trailer plug in.    Also consider using the product called "Salt-Away" when you flush.  Add this to your flush.   Nothing will totally stop salt rust, but this stuff really does help. 

Now For Some How To Do It Information:


Replace Bearing Races ;  To replace the bearing races, use a hammer to start the race, tap one side, then about 120 degrees, tap it again.  Keep moving around tapping & moving about 1/3rd  of the race at a time.  Once it gets deep enough that the hammer is no longer  is useful, then use the same long punch used to remove the old one and tap it in as before.  When the race is all the way in & seated, the noise of the tapping will change from a thud, to a ringing type noise, meaning it has bottomed out against the shoulder of the hub.  

Hub Bearing Packing for Non-Bearing Protector Units ;  When installing bearings in a hub or hub drum for a spindle axle not using bearing protectors, it is necessary to pre-pack the bearings prior to installing them in the hub.  To pre-pack your bearings, you can buy a bearing packer at your local auto parts store, or you can pre-grease your bearings using grease in the palm of your hand and work the grease into the bearing.

The bearing packing tool contains two convex shaped plates attached to a threaded rod that has a Zerk grease fitting on the end of this threaded rod.  With the bearings in the packing tool, and clamped down, you pump grease into the Zerk fitting, forcing grease through the rollers of the bearing.  This bearing is now ready for installation into the hub.

If you do not have a bearing packing tool, you can achieve the same results with by forcing the grease into the bearing by hand.  Although this is a messy process, it is equally effective if done properly and carefully.  You need to have CLEAN hands, put grease in the palm of one hand and then with the other hand, roll and rotate the bearing into the grease, carefully forcing grease through all the rollers.  Once you have pre-packed both the inner and outer bearings, carefully lay them on a clean surface.  Dirt in the grease of a newly packed bearing will act as an abrasive on the bearings and races and can very quickly shorten your bearing life.

Next lay the hub or hub drum face down on a flat surface and fill the rear of the inner hub cavity with liberal amounts of grease, carefully coating the rear race surface.  Now install the inner bearing (the bearing next to the seal) into the rear of the hub, matching the cone of the bearing to the race. DO NOT INSTALL THE BEARING IN BACKWARD, THE TAPERED PARTS HAVE TO MATCH!

 Now, with the pre-greased inner bearing sitting in the hub drum, add more grease on top of the rear bearing.  There will be a space of about 1/4" between the inner bearing and the seal. It is essential that this cavity be filled with grease.

To install the double lip seal, the inner lip with the inside coil spring  goes toward the inside the hub.  Set it squarely on top the rear hub bore.  Now set a wood block on top of the seal, and tap the block with a hammer until the seal is flush with the rear hub bore.  Be careful not to distort the seal by tapping unevenly.

This completes the rear bearing and seal installation.  At this point, turn the hub over on the flat surface, being careful not to get dirt or filings into the grease at the rear of the hub. Now pack liberal amounts of grease in the inner hub cavity.

You are now ready to slide the hub or hub drum onto the spindle.  Clean the spindle with a clean rag. (NOTE) The inner surface of the bearing and the spindle shaft are machined to close tolerances.   If the spindle has been burred, is unclean, or if the rear bearing is not square with the spindle shaft, the bearings may temporarily hang up as you slide the hub in place. Once the hub or hub drum is fully in place on the spindle, slide the outer bearing onto the spindle and into the hub.  Match the cone of the bearing to the race. AGAIN,  DO NOT INSTALL THE BEARINGS IN BACKWARD!

Install the spindle washer and spindle nut onto the spindle with the hub and bearings in place. 

Hub Bearing Packing for Bearing Protector Units ;   These units will be packed basically the same as the non-bearing protector units.  The exception is that they do require the lower viscosity grease, and that they do not need to be packed as completely as the non type since they do have the Zerk fitting for greasing after installation.  Do not rely solely on the Zerk grease fitting on the bearing protector to up all the grease into the hub, pack as much as you can get in by hand.

Pre-Load the Bearings ;   At this point you are ready to install the hub and Pre-Load the bearings. Whenever you install new hubs or replace bearings and races into existing hubs, you should pre-load the bearings.  Pre-loading the bearings assures that the races in the hub are 100% in place and against their machined stop points. This assures that the hub is tight and does not loosen up and start wobbling after a few miles.

To pre-load the bearings. Tighten the spindle nut Finger Tight, or until it comes up snug, and then with a crescent wrench or channel-lock pliers, tighten the spindle nut another flat of the nut.  Now rotate the hub four or five revolutions in both directions. This should fully seat the races.  Loosen the spindle nut, then re-snug to finger tight as before, engage the nut retaining device.  Some spindles use a washer that fits a groove or flat on the spindle, and that has a tab that is bent over one flat of the nut for the retaining device.  Others may use a thin sheet metal cap,  with depressions that go over the spindle nut, with the cotter pin going thru opposing slots and through the spindle. This lock nut has the slots in slightly different locations so that exact tightness can be accomplished.  Still others may use a "castle nut".  This castle nut is a regular nut that is longer with slots on the outer end for a cotter in to pass through. 

Never run your spindle nut Overly Tight, this will cause your bearings to over heat. And cause premature bearing failure.  Never run your bearings too loose.  A slightly loose spindle nut will run for many miles, but if it is very loose the individual rollers may come apart in the bearings, causing lots of trouble.  

Push a proper length cotter pin through from the top, either bend the bottom inner end inward and the outer half up and over the end of the spindle, or bend one end forward and the other rearward, to keep it from coming off.   Note that the dust cover or bearing protector has to move freely and not contact the cotter pin.

You are now ready to install your dust cap or bearing protector.  A short piece of 2" I.D. water pipe makes a good tool to install a plain dust cap.  Most of the bearing protectors, are simply hammered in with a plastic mallet.

On your initial run of highway travel, after 20 to 30 miles pull off in a safe area and check to see if the hub is loose on the spindle.  At this time it is also advisable to put your hand on the spindle to check it for overheating.  It will be warm, but should not be hot.  Check the other spindles also to get a idea as to just how warm they all are.  If one is hotter than the others, investigate the matter.  A spindle can become hot not only because of a overly tight nut, but because the brake lining is dragging on the drum.  A spindle can also become hot if the bearings have rusted during the winter off season.

At this time if you have a light to medium weight boat, try to pull and push the tire in and out a few times.  If your boat is large, you may have to jack it up to check this.  If your hub is loose, you will need to re-snug the spindle nut and re-engage the nut retaining cotter pin or tab washer. This tab washer type may be designed to have more than one tab for subsequent usage.  In use, one tab is bent over to lock the nut flat, once you get the proper nut tightness.   It is not advisable to straighten and reuse the same tab again on the tab washer, as it may break, allowing the nut to then loosen up by itself while under tow.  

Trailers with Brakes ;  It is advisable after you pull the brake drum off the spindle to take a digital picture of the locations of all the internal parts so that you have a better chance of replacing them correctly.

With most of the trailer brakes being drum type, we will be referring to them unless specified.  If possible purchase replacement parts that are galvanized, not painted.  If the hydraulic wheel cylinder is frozen up and you can not get the piston out because these units only activate from the front instead of from both sides like a car, you have 2 choices.  Replace it, or if you are in a situation where you need it ASAP, you can press the rusted piston out with hydraulic pressure from a grease gun.  Here you will need to make an adapter using a brake line threaded end and silver solder a Zerk fitting to it.  Sometimes you can not remove the wheel cylinder without rounding off the corners of the brake line fitting that goes into the cylinder from the back,  and you will have to break the line off.   If this is the case you will need to replace the line, but you have 1/2 of the makings for this Zerk adapter now.

With the wheel cylinder off the backing plate, the adapter you made and screwed back into the brake line hole, you can simply attach your grease gun to the Zerk fitting, pump enough grease into it to force the stuck piston out.    Many times the problem is that there is a slight corrosion between the aluminum piston and the internal cylinder walls.  If this is not bad, you can scrape it clean with emery cloth, sand out the buildup, or use an automotive wheel cylinder hone.  If it will not clean up, then replace the wheel cylinder.

When repairing or replacing a wheel cylinder for whatever reason, there is one variation on reassembly as compared to automotive installation that is different  After you have installed the piston,  use a slight amount of your wheel bearing grease, smear some of it the inside of the wheel cylinder on the OUTSIDE of the cup, under the rubber dust boot.  You just want to seal water from leaking between the cylinder walls and the piston, as this is what causes the seizing them up.  Be sure that none of this petroleum grease gets behind the piston and on the wheel cylinder rubber cup, as it will deteriorate it causing more problems.  Also smear some at the groove where the boot snaps onto the wheel cylinder and at the piston activator rod to act as a seal.    Remember that these parts, even though they are sold for boat trailers, are in reality just conventional automotive parts that are only designed to keep out DUST.  

The above paragraph will help keep saltwater from rusting the cylinder bore that is outside of the contained part that is oiled by the brake fluid.  If the outer bore becomes rusty, you may experience (1) no brakes, if the piston can not move far enough to activate the brakes. (2) if it does activate, it may not have enough spring tension to overcome the rust & not allow the brakes to return to normal.   If this happens your brakes will be on all the time until something wears down, or gets so hot that you then will know you have a problem. 

Before you re-assemble these parts you may want to consider sand blasting all the internal parts, or at least wire wheeling the rust off.  Then use a spray coat of CRC Heavy Duty Rust Inhibitor #06026.   This is very akin to the WWII cosmoline.  Off the can it reads "Flexible, amber coating that protects and preserves metal surfaces, electrical connections, engine components and fasteners subject to salt spray along with high humidity.   Also provides effective protection  for steering and throttle linkage.   Will not crack or craze.   Resists wash-off and abrasion while providing long-term protection.  Forms a corrosion-proof insulating film."

Coat each part with this inhibitor and let them dry before you assemble them onto the backing plate.

 In 1971 J. Standard Baker Quoted " Drivers Towing Trailers  Are Four (4) Times As Unsafe As Those In Cars Alone! 

If disc brakes are used with a hydraulic surge brake coupler, it is extremely important that the residual valve (check valve) of the brake coupler be punctured or removed from the master cylinder.  Failure to do so will maintain 10 to 20 lbs of hydraulic pressure on the disc brake units, and will lead to rapid brake pad wear, and possibly the failure of the brake system.   It is also very important that the orifice in the tubing adapter at the rear of the master cylinder of the brake coupler be a minimum of 1/16" ( .0625 ) or larger.

A brake lock-out mechanism will be necessary for backing up when using disc brakes with a hydraulic surge brake coupler.  This is most often done with a reversing solenoid valve, which when connected into the back-up light circuit of the tow vehicle will disable the trailer brakes, allowing the vehicle to back up.

If a manual lock-out pin is used to lock out the brakes during backing-up operations, it is critical that the lock-out pin be removed from the lock-out position during forward highway use, or the trailer brakes will not operate when needed.

Be sure that the surge brake coupler will compress and telescope forward during braking and towing operations.   If the brake coupler will not pull out (telescope) during towing operations, pressure will be maintained on the disc brakes while towing, and they will over heat during highway travel.

It is also essential that you confirm that the D.O.T. required break-away cable on the surge brake coupler is in the towing position and not in the emergency break away position while towing forward.  If the break away cable is in the emergency break away position during highway travel, hydraulic pressure will be maintained on the trailer brakes and they will overheat, and may fail.

Tires ;   It should go without saying, don't leave home without a spare tire.  For trailer application, it is essential that you select the correct tires to match your application and capacity requirements.  (ST) Special Trailer tires are normally more expensive than (P) Passenger car or (LT) Light Truck tires, because they are built tougher with more material and are more bruise resistant.  This is necessary because most trailer suspension systems are stiffer and less sophisticated than automotive suspension systems.  Consequently the trailer tires must be capable of withstanding more abuse.

Tire inflation pressure is one of the most important factors in tire life.  Tires should be inflated to the pressure recommended by the manufacturer for the load.  Pressure should always be checked cold before operation.  Pressure will increase as the tire gets warm from the trailer being towed any distance.  Check inflation pressure weekly during use to insure maximum tire life and monitor your tread wear.

The last letter of the tire designates its load range and equates to the amount of air pressure required.   Tires with Load Range "B" usually max out at 35 PSI; Load Range "C" can go to 50 PSI.  Inflating the tires to about 90% of maximum pressure is suggested.

The following Tire Pressure Chart lists the standard recommended pressure for most common trailer tires.

From the above chart it can become obvious that regular automotive tires with an inflation of from 27# to 32# will not handle the load that most boat trailers require. 

The load range/ply rating branded on a tire's sidewall identifies how much load the tire is designed to carry at it's industry specified pressure.   Today's load range/ply ratings do not count the actual number of body ply layers used to make up the tire's internal structure, but indicate an equivalent strength compared to early bias ply tires. Most radial passenger tires have one or two body plies, and light truck tires, even those with heavy-duty ratings (10-, 12- or 14-ply rated), actually have only two or three fabric plies, or one steel body ply.

Special trailer service tires are often available in multiple load ranges. The appropriate load range is identified immediately following the size's rim diameter as ST205/75R15 C, with the C being rated at 50# pressure while the Ds are rated at 65# and can carry a heavier load.  

One recommendation is, with a felt marker pencil is to mark on the fenders near the tires, the pressure that you try to maintain in those tires.  This helps for those of us who tend to forget.

The one thing that should be mentioned however, is that if you carry a spare trailer tire and wheel mounted flat on the tongue of the trailer, be sure that the valve stem is positioned so it is pointing DOWN.  If this is not possible with your mounting situation, then at least position the wheel so that the stem is behind the winch handle to help keep you from stepping on the stem.   If you are like many who walk out on the tongue during the reload at the launch, you can very easily step on this stem, breaking it off.  Then when you really need a spare, it has been damaged, and possibly not known.  Then when you need the spare, it is flat.

Trailer Ball Height ;  The theory is that the trailer and tongue should be road level when attached to your towing vehicle.  For proper load distribution you want the trailer frame to be close to level to the road.  This is more important with dual axles than a single axle because the load needs to be distributed evenly on BOTH axles.  If not, you can be exerting  way more weight on your rear tires than they are designed for & can have premature tire failure, like a BLOW OUT.  You may even have the rear tires dragging on the underside of the fenders.

I have heard  that ball height is also more important when using a trailer the hydraulic surge brake set up. The word is if the tongue is too low then the trailer will apply pressure to the surge brakes towing on level ground.  Then when you do need your trailer brakes, they would be much less effective because of all the heat.  If the tongue was too high then the brakes would not apply as quick or hard enough as a properly hitched trailer would.   This however slightly controversial and I would like for someone to explain to me in detail.

On many larger tandem and triple axle torsion trailers, the height to the top of the hitch ball should be from 17 inches to 21 inches above the ground when loaded.  This balances the load properly on the trailer.  An inch or so either way is OK as the weight of the boat changes with full fuel tanks vs. 1/2 or less etc.

On most modern towing hitches that use the 2" square receiver frame mounted, you can buy removable hitch extensions with the correct drop or lift to accommodate your needs at most automotive / marine stores.  If you buy a different towing vehicle,  you may have to change the removable hitch to a different height because of a new set of circumstances. 

 Trailer Maintenance ;  Trailer maintenance is also a ongoing thing, especially if it is used in saltwater, as for tearing down & replacing wheel bearings & lights.    Even cleaning it up & repainting occasionally is needed.

The principle these units are trying to avoid are. -- When backed into the water for launching, boat trailer wheel hubs, heated by recent travel, are suddenly cooled. Air inside the hubs contracts and a vacuum is created. Water and dirt are sucked into the hubs between the seals and the spindle.  Corrosion will set in immediately.  Bearing failure can be expected within two seasons in fresh water - one season in salt water. 

There are a quite few different manufacturers of these units.  The most common and original brand, being Bearing Buddy® at ,  Trailer Buddy® Products ,  Red Eye® Kodiak Trailer Disc Brakes at,  Tie Down bearing protectors in either the steel or the bearing covers in the clear plastic style at   The clear plastic are very similar to the Bearing Buddy, but it is clear where you can see the grease inside the hub.  Bearing Saver, made by Progress Machine and Tool,  Attwood "Hub Mate" and Fulton now make a copy of the Bearing Buddy. 

These units are designed with a floating piston backed up and using internal spring pressure to constantly keep grease pressure on the bearings.  The axle hub is filled with grease until the grease forces the piston outward about 1/8 inch.  Because the outer side of the piston is spring loaded, the piston exerts a slight amount of pressure (about 3 PSI) against the internal grease, which maintains a slight pressure between the inside of the hub and the outside environment.  If the seal surface of the spindle is not damaged in any way, when the hub is submerged, water cannot enter the hub because of this pressure.

When using these systems you need to also use the lighter weight grease, otherwise the piston can not overcome the higher viscosity of the grease to force it into the bearings.  The instructions of the Bearing Buddy say to check the lubricant level prior to launching or when the hubs are warm by pushing in on the edge of the piston,  If the piston moves or rocks, the hub is full of grease.  If the piston does not move, then add grease with a hand grease gun until the piston starts to move outward.  The word here is, STARTS TO MOVE, do not keep pumping, as the piston will move all the way out to it's outer stop and you can them build up enough pressure inside to force grease out the rear seal, or the rear seal either out of the hub, or the bearing buddy off the outside.  Be careful not to overfill.  It is better to drive for a while allowing internal air to dissipate, then stop and refill if necessary a few times than overdo it initially.

Reliable Sure Lube, and Spindle-Lube® utilize a different internal pressure system.  The Sure Lube system found on EZ Loader trailers, uses a bleed off hole in the spindle inside the seal that bleeds excess grease out through a hole in the center of the spindle.  The spindle is welded on top of the axle so there is a escape hole out the rear of the spindle.  This hole being plugged with excess grease, stops the water from seeping backwards into the spindle/bearing area.   This unit can cause problems unless the hole in the back side of the spindle is cleaned of hard or caked grease periodically.  Otherwise you may overfill the hub cavity, and force grease past the rear seal which will be un-noticed until later when it gets spattered all over the brakes, making them in effective and starts dripping out the backing plate.   Grease on your brake linings will drastically decrease your braking capacity.  But by then water has also leaked inside the hub & into the bearings.

Some of the new hubs have a grease fitting on the rear side of the hub.  The idea here is to force the grease from the back out thru the bearings to the dust cap.  This is supposed to lube the inner bearing (most important one) better and take some pressure off the seal.

Now comes along the oil bath system, which does have it's benefits.  They are pretty well trouble free.  There are a couple of things to watch however.  If the color of the oil starts to get a gray color, that would indicate there is a water leakage into the oil somewhere.  If this happens you could quickly see if the leak was coming from around the plastic cap because of oil seeping out also.   However it will usually be the rear seal.   No matter the reason it would be best pull the hub, check the rear seal also.   On the Reliable Oil Bath version to remove the outer see-thru cap (early ones were all clear plastic, later aluminum with a clear plastic viewing window) this can be done you using a large channel lock wrench to un screw it.  Once this cap is off, the rest is the same as all the other ones.  Clean, replace any damaged components and refill the hub.  Check the seal between this cap and the hub.  This hub is refilled thru a refill plug as seen in the RH photo above.  Replacement new style caps are less than $15 each.

There are a couple of words of caution however for these oil type hubs & that is IF the trailer sat for a considerable length of time, like over the winter, move it so that the oil has a chance to re-lubricate what was the top of the now dry bearing.   Also the word is that if it is cold to not to hook onto the trailer & start driving 70 MPH  right off the bat as bearing life may be reduced for the same reason. 

Grease ;   Grease is made in two different types.  (1) is chassis grease, identified as LB.  (2) The other is wheel bearing grease, identified as GA, GB, or GC.  A multi-use grease will be identified as GC-LB.   It is is advisable to NOT mix one brand of grease with another or unknown brand.  It is also advisable to find a good brand that is readily available from many different sources, so if one store is out, you can purchase it from the other.  

You will find grease cartridge tubes for the small 3 oz. grease guns designed to be carried with the boat.  Information on some tubes may say protection from corrosion of salt-water, others may say high temperature grease, or a combination of these two.  The high temperature meaning, 550 degrees F. melting point.  Be sure that the grease you use is a Low or Medium Viscosity (high temperature) grease. This low to medium viscosity (thinner) grease will flow around and through the hub cavity and the bearings, providing more lubricant to the bearings than a high viscosity grease.  High viscosity (thicker) greases will be thrown to the outer hub cavity wall by centrifugal force of highway driving, where it tends to stick, with only a small amount of grease left in the bearing rollers to provide lubrication.

Low viscosity grease will have about the consistency of room temperature Vaseline.  I have found Lubrimatic 11400 Marine Trailer Bearing Grease to be easily available and works quite well.  A 3 oz. four pack usually sells for from $10 to $14.00.

For the oil bath hubs, EZ-loader which uses Reliable hubs, recommends  50W SAE automotive oil (however you may have problems trying to find any).  But the latest is to use a outboard lower unit synthetic gear oil of 80-90 weight.   My EZ loader dealer says the factory uses and recommends regular Yamaha gear oil.

Axle Seals ;  All axles will have a rear seal to keep the grease IN, however for those of you who think a LITTLE is GOOD, that a LOT is BETTER, you are WRONG.  When pumping grease in  with your grease gun, DO NOT over grease as you will simply max out the internal capacity of your hub, then force grease past your Bearing Buddy on the outside,  AND also out the rear seal on the inside that you can not readily see.  You will se this inner grease later as it will become splattered all over your wheel's inside surface AND possibly on the underside of the boat.


When servicing an axle. you should also NEVER consider reusing a seal that has been driven out of the hub, except in an emergency, as they almost all of the time can get misshaped on removal.  The seals are the most important item here to keep out the water.  Now, here is one important bit of information.  Many of you will usually buy the bearings at automotive supply stores, probably because they are closer than the marine store.  But they normally can not cross-reference the numbers for the marine seals.  They will have to measure the old seal to come up with a seal the same approximate size that will fit.  However these new  automotive seals will only have a single sealing lip that comes down to the spindle basically straight and NO inner coil tension spring.  That said, remember here I said NO inner coil tension spring, the last ones I got (2017) for my lake boat trailer were from an automotive parts store, so maybe some brands have updated, but the price was higher.

Most marine seals have a single or double sealing lip with a circular coil spring inside the lip putting more tension on the seal surface.  The neoprene seal lip will come down to the spindle and then protrude inward almost 1/2 the width of the metal part.  You might get by with a single lip automotive seal if the spindle seal surface is totally smooth and with no rust or pit holes.  Is it worth the potential problems of using an inferior type seal only designed to keep out highway dust, instead of salt water?  The right seals usually sell for from $2.50 to $3.50 each at marine supply stores.  As with the bearings, write down the numbers off the seal, also measure the spindle dia. of the seal area, and the dia. of the outside of the seal, plus the total thickness of the seal body.

It is also most important to use a strip of emery cloth and "shoeshine" sand the seal surface of the spindle when you replace the a seal.  The reason is that just possibly the new seal may be a different make, and the new lip is not bearing exactly on the same spot of the spindle as the previous lip did.  With this in mind, there could possibly be some rust or slight roughness in this new location.  Spindle roughness here can very quickly ruin a new seal, allowing water in and causing bearing failure.  

A faulty seal will allow salt water to enter the hub and then ruin bearings in less than 2 weeks time.  Believe me as it happened to me on the return 200 mile fishing trip.  That was the basis for writing t
his article.

  Copyright © 2001 - 2017  LeeRoy Wisner  All Rights Reserved

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Originated  05-23-2001, Last Updated 10-31-2017
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These brakes shown above were serviced with a new wheel cylinders installed, & the other internal parts repainted with Rustolium, just a year before.  The trailer was used only 4 times in salt water, but from launches that did not have fresh water wash-down facilities.


(8) There also are also a few pre-requisites.  Always carry a tool box that is adequately stocked with tools and emergency type accessories.  Have a lug wrench and proper jack.  Carry some wooden blocks for blocking and to act as chocks in front of and behind the opposite tire.

(9) Also one thing to consider is that if you are trailering a heavier boat and your towing vehicle has an automatic transmission, is when you are reloading the boat onto the trailer at the launch, upon initially backing down the ramp, when you stop, place your emergency brake on BEFORE you put it in PARK.  What this does is removes the possibility of damaging the parking brake dog in the transmission.  In reloading the boat, there is a good chance that the weight of the boat will drag the vehicle back slightly, binding this internal parking brake dog.  Have you done this and have trouble getting the the shifting lever out of park, or it makes a loud snapping noise when you do get it out?   The emergency brake is designed to hold 80% of the vehicles weight on a 10% incline with the vehicle pointing downhill.  That is why the owners manual recommends that you apply the emergency brake anytime you park on an incline.   It keeps the stresses to the transmission lock dog to a minimum.  Parking brakes on a downhill slope like boat launches, the parking brake looses much of it's efficiency, because of the design of the brake shoes.  Do not put a lot of faith in parking brakes in this situation, USE WHEEL CHOCKS.

(10) When retrieving the boat with a automatic transmission and you might be off the lower end of the concrete with your pickup rear tires on gravel.    You do not want to spin your tires and become stuck, set the gear selector in 2nd, hold the foot brake on, increase the accelerator until the motor starts to bog down, then release the emergency brake.  Do not race the engine, but let the transmission slip and you will move up the ramp slowly.  If you had put it in 1st, you could have spun.  However being in 1st is preferable to trying to get it in either drive or 2nd and missing either then being in neutral, which can be disastrous when you let off the brake.   This works in most domestic pickups as doing it this way, starts in 2nd not in 1st as most drivers may believe.

(11) When retrieving the boat with a manual transmission, set the emergency brake and leave it.  Get the boat all loaded on the trailer and ready to pull out. With the emergency brake still enabled, put it in 1st and S-L-O-W-L-Y start letting out the clutch as you give it gas.  When the engine starts to bog down, immediately pop the emergency brake, and if your timing is right, you will yank the boat/trailer right up the ramp without even spinning a wheel! 

(12) Another safety device is to use chocks.  Some will use one behind each rear tire with a rope attached to each & snap the other end into a hole in the rear bumper.  There are a few boaters that only use one behind the drivers front tire.  They then attach a small rope long enough to bring it into the drivers door or window.  As they drive up the ramp, all they have to do is pull the chock up & out of the way.

Maintenance:  All Types

      Check your spindle for warmness, and the Bearing Buddies for proper grease content each time

             you start from home, or the launch, and have driven a few miles to allow the grease to

             warm up.  They should be slightly warm to the touch.

    2.   Check the bearings and repack hubs annually if necessary before each seasons use 

    3.   For oil pack hubs, inspect the oil level each time you use it, refill if it gets low

    4.   If need be, replace the seals annually

    5.   Check your lug nuts or bolts for tightness.

      Check your tire air pressure every few months, be sure to also check the air in the spare
      Every few years remove the leaf springs, sandblast and repaint them with Rustolium paint
      Carry a spare hub assembly, or at least a new set of bearings & seal.


Maintenance:  Brake Type

      Check the shoes for wear and adjust the brakes annually or every 2000 miles.  Check for

             grease leaking on brake shoes.  Wash brake pads with brake cleaner if necessary.

   10.   Check fluid level of the master cylinder before every use.  If fluid level gets low, check for

              leaks at tubing connections and wheel or master cylinders.

   11.   Lubricate moving parts of surge brake unit annually.

   12.   Flush the internal brake unit / backing plate out with Salt-Away to help remove rust on drums
                  (salt rust will cause drum and brake lining wear prematurely).

   13.   Carry spare brake fluid with you.


Maintenance:  Disc Type

   14.  Not a lot to look for here other than check the bearing grease.