Trailer Bearing Failure and Replacement

[Starscream]

I thought I'd start a thread about my recent trailer adventure, and document the repair.

I lost a bearing on the highway on the way to launch this year. I knew that I had to change it, because I felt a little roughness in the rotation when I took the trailer off its jackstands this year. I store the trailer with the weight off of the wheels, and spin the wheels as often as weather allows. In my spring wheel-spin I could tell that the wheel was rough. So, lesson learned: don't ignore even the smallest roughness in a wheel verification.

I made it safely off the highway with the wheel attached, but it came off in my hands when removing the lugs. It was just the rust around the brake drums that kept the wheel attached as I exited the highway.

A ratchet-strap is a good piece of kit to have, to strap up an axle to the frame (on a dual axle trailer) if one wheel departs. So is a 12V air pump and extension cord, to bring the remaining single-tire up to its max-load pressure (I run at 50 PSI on 4 wheels, but on 3 the single wheel should be at 65 psi). I'm also going to add two Bulldog trailer jacks welded on to the trailer frame just behind the axles. They will be used instead of a jack for the next inevitable problem, and also make storing the trailer easier. The SUV jack is just barely up to the task, and takes a lot of effort.

Here's a large-size image of the trailer on the side of the road. The stress on the remaining 50 PSI tire is apparent.



All that was left of the assembly was the castle nut and some shreaded bearing parts. The spindle was all scratched up, but still looks perfectly straight. The inner ring of the inside bearing was left on the spindle; the ring is visible in the photo below:



Parts should be here later today. I'll post progress photos.


This is the first time that I've done trailer bearing work, so I didn't know any of the parts. I didn't realize that the inner bearing ring was still attached as I first looked at it. I was able to use the hook-end of a hammer to bang the ring off of the spindle, and used a file and sandpaper to smooth out the spindle. With a bit of grease and some effort, I can now get the old ring on and off the spindle.

The new parts are on order. The bearings, cups and seals were only about $15 each, so $30 per wheel. I ordered a new back-plate and electric brake drum, and I'll post the total cost a bit later.

For those as unfamiliar as I was with the assembly, it looks like this (upper row for my trailer):


The backplate of the brake assembly (part 20) has four threaded studs that go through the four holes on the spindle (the un-numbered part on the diagram above, at the far left). There are four nuts to install from the back of the spindle to hold everything in place. I found that my brake assembly only had three of the four bolts installed, and the empty stud was well rusted showing that it had been like that for a while. I didn't even know that was something to inspect.

[Jimmyt]

Wow. Hate that happened, but glad it wasn't any worse. The inner race shows you had quite a bit of corrosion in the inner bearing. There is a good bit of pitting on the axle just inside of the inner race. I can't tell for sure if that is the sealing surface, but if it is, you'll want to get that as round and smooth as you can so the new seal [1-1A] will keep water out. (Sorry if I'm telling you stuff you already know).

The joy of owning a boat; you never have too much free time on your hands.

Thanks for posting. Looks like you've got a grip on it.

[Ixneigh]

So it’s only the integrity of the two bearings that keeps the wheel from falling right off. That’s kinda scary.

Ix

[Jimmyt]

Tapered roller bearings in opposition will keep the hub in place easily, until the rollers start coming apart. As they corrode or start to flake apart due to lack of lubricant, grit, etc, then you get clearance in the fit-up and it accelerates wear. Then, it spits out a worn roller or two and clearance opens up enough to spit out rollers that aren't even worn.

You've got to spit most of the rollers out of the outer bearing for the hub to come off, but once enough of them are gone, the hub will come off unless the keyed washer is large enough to catch the outer race of the outer bearing. Of course, even if the washer or nut catches it, the hub flopping around at speed with a couple thousand pounds load on it is going to tear the hub off fairly quickly, regardless.

Looks like there were rollers loose in the hub - based on all of the dents and dings in the axle.

[Starscream]

Well, I was planning to document the fix, but with the amount of grease involved in the job I had to put my phone away.

The new brake drum came with the cups already installed (parts 3 and 4).

The brake assembly was a simple 4-nut replacement.

Packing the bearings was easy, using the you-tube technique of a big glob of grease on the palm and then a scooping motion to fill the gaps. Pop the rear bearing in place, cover with a clean rag, and tap the seal into place with a block of wood and a hammer. Plenty of youtube videos to show how to do this, no special tools required.

The new assembly went in to place much easier than I thought it would. I had cleaned up the spindle before with a file and some sandpaper, so that seemed to work. I wasn't convinced that the assembly was on far enough, so I spent some time comparing with the other wheel, and hammering the drum through a wood block to try to make sure it was well seated. Then I overtightened the castle nut a bit to see if that would cause the drum to move inwards more, but nope. Backed off the castle nit a bit, and the job was done. Oh, my system didn't use a cotter pin, instead there's a second very thin washer that goes between parts 6 and 9, that had a little metal tab that bends up between the turrets of the castle to keep it in place.

Yes, its only the bearings that keep the wheel on the trailer. If the bearing go, so does the wheel. I agree, the spindle was really battered by the bearing destruction.

I drove around a bit checking brakes and wobbles and bearing temp, and everything worked great. The new bearing was less warm than the other three.

I have the parts to repack and change the other three bearings, but I'm trying to decide if I need to replace the cups or just re-use the existing ones. I'll do the other three bearings tomorrow afternoon, and launch on Friday if things go well.

Repacking the bearings seems to be a very simple job that anyone can do, and very inexpensive. I'll confirm that tomorrow though, after I do the other three. I read somewhere that Geico says 25% of trailer insurance claims come from lost bearings/wheels. My trailer is 8 years old and it's probably 5 years since I did any serious bearing maintenance. My mistake...almost cost me big time.




The old bearings are on the top rag in the photo, I mean, what's left of the old bearings. The two new ones and the grease seal are on the bottom rag.

[Jimmyt]

Well, I was planning to document the fix, but with the amount of grease involved in the job I had to put my phone away.


I have the parts to repack and change the other three bearings, but I'm trying to decide if I need to replace the cups or just re-use the existing ones. I'll do the other three bearings tomorrow afternoon, and launch on Friday if things go well.

Yep. I usually wind up with grease everywhere when packing bearings. Wouldn't want to risk getting my phone in the action, either.

You shouldn't re-use the outer races (if that's what you mean by cups). Always replace the entire bearing assembly, including the outer races. It won't take much longer to drive out the old ones and put in the new ones. Be careful not to nick or scratch the new ones when putting them in. I have a collection of old outer races that I have ground down the O.D. so they won't get stuck in the hub; that I use to press the new races in with - using a hydraulic press. But, there are a lot of reasonably priced bearing install tools that can be had.

Looks like you're quickly mastering this skill set! Congratulations!

[Sheppie62]

The temperature of the hubs is a fairly easy way to judge the condition of the wheel bearings. I use one of those laser thermometers each time I stop to check load, or use your hand with a glove. If one is higher temperature then it’s damaged or to tight, or needs grease. You probably already do this,

[Be Free]

Jimmy has it right. Always replace the entire bearing. Don't try to reuse the races. It is a false economy and more work in the long run.

You mentioned using sandpaper on the spindles. As badly as they were gouged that would have been the first step. Hopefully you used emery cloth on the final step before installing the bearings. It will get everything back nice and shiny with no scratches. Keep a close eye on the tire wear and temperature of that axle on your next long trip. I'm a little concerned that you may have a loose fit on the spindle due to the amount of metal you would have to take off to remove those gouges.

For those new to trailers: You need to remove your hubs and repack your bearings annually. Jack up the wheel and spin it. Any rumble or vibration when you turn the wheel by hand is a sign that the bearing has gone too long without service. Plan on replacing noisy bearings. They are cheap and a failure, particularly on a single axle trailer, can mean the loss of your boat, tow vehicle, and possibly injury or death. It's not something to take chances with. Don't pull a trailer with noisy bearings.

If you've never repacked bearings before start out by familiarizing yourself with what a good bearing looks and feels like. It will be shiny, have no rust, pitting, or corrosion on it anywhere. It will turn easily and quietly in your hand. There will be very little "looseness" in the bearing. If your old bearing has any corrosion, pitting, or if it feels "sloppy" when you manipulate it just replace it. They are cheap! Shiny is good; not shiny means replace.

You can pack your bearings by hand or with a bearing packer. Both work equally well if you do it right. Using the packer is usually a little cleaner and a little faster. On a single axle trailer it's a tossup which one I'll use. On a double axle I usually break out the packer.

On a new bearing, packing is the process of squeezing grease into the new bearing. Just keep squeezing it in until you see grease coming out of the top all the way around. You can reuse what comes out of the top. It is perfectly clean grease.

If you are servicing an old bearing you are not only putting in new grease you are forcing out the old, dirty, contaminated grease that is still in the bearing. Even if it is just old and not contaminated it needs to come out. Keep forcing in new grease until you see new, clean grease coming out all the way around the top of the bearing. Do not reuse any of the old grease.

Always replace the grease seal on the back of the hub. Never try to reuse it. Always use a double-lip seal. They cost a little more but they keep the water out as well as keeping the grease in.

Always use a dust cap (or bearing buddy type cover). This will keep dirt and water out of the outer bearing. If you use a bearing buddy type device do not over pressurize it. More is not better. Too much pressure will either loosen the bearing buddy (and it will fall off while you are driving) or it will mess up the grease seal. Stop just before the outer plate touches the rim.

On long trips, plan to stop and check the tires and hubs within the first 20-50 miles. If either is getting hot you need to find out why. An IR thermometer is a good tool to have for checking hub temperature. If you use your hand hold it close to the hub first to make sure that it is not going to give you a blister if you touch it. Warm is OK. Hot is bad. That goes for the tires as well.

Also, on the subject of long trips: if possible, let your hubs cool off before you launch. A hot or even warm hub immersed in water can suck in water through the grease seal as the hub cools and the pressure inside decreases.

Stay safe!

[Be Free]

.... I have a collection of old outer races that I have ground down the O.D. so they won't get stuck in the hub; that I use to press the new races in with - using a hydraulic press. But, there are a lot of reasonably priced bearing install tools that can be had.

Looks like you're quickly mastering this skill set! Congratulations!

"Hydraulic press". Aren't you fancy! I'm firmly in the 2x4 and hammer category!

[Jimmyt]

"Hydraulic press". Aren't you fancy! I'm firmly in the 2x4 and hammer category!

Nothing wrong with a 2x4 and hammer. When I was young, my dad had a brass block that we used to hammer races in. The brass was soft enough to not damage the races (albeit not as soft as a 2x4).

Never been accused of being fancy.

The Admiral's dad was a working man, who appreciated people that could do actual work. He wound up with two son's-in-law that liked to work with their hands. Every Christmas and birthday, he'd buy us a tool. He was a great guy, and is sorely missed. The press was his doing. I've used it a lot.

[Starscream]

Good advice guys, thanks.

For this year, though, I'm going to re-use parts 3 and 4 (the outer races press-fit into the brake drum). I'm just not equipped to get them out and get the new ones in. I took them out of the drum I replaced for practice, and that was hard enough to convince me not to do another one.

I'm a bit concerned about the spindle, too. I sanded it down to 240 grit, then washed and greased it. The wheel feels as tight as the others, spins noise-free and ran cooler than the other three on the test drive.

I've finished replacing two out of three of the remaining bearings. The old ones look really good, but I think I feel some axial looseness in them.

Details to follow

[Jimmyt]

I'm a bit concerned about the spindle, too. I sanded it down to 240 grit, then washed and greased it. The wheel feels as tight as the others, spins noise-free and ran cooler than the other three on the test drive.

The spindle needs to have good threads, and a good surface for the seal to run on. The surfaces, where the inner races contact the axle, can be pitted, chipped etc, and still be serviceable; if the inner race fits firmly on the axle. If the inner race flops around on the axle, then you have a problem. The sealing surface is where you typically have an issue. As Bill says, double lipped seals are the way to go. No matter how dinged up the axle is, the threads, sealing surface, and inner race fit are the only critical things. Well, it needs to be structurally sound...

You could get repair kits in years gone by, to sleeve over a bad sealing surface and use an oversized seal - thus giving a permanent repair to a damaged sealing surface on an axle. Don't know if that sort of thing is still around, though.

I use a steel rod to knock the outer races out with a hammer. Should take less than two minutes per race. If you have a bench grinder, you can grind the outside of the old races down so they just drop into the bore without sticking. Then, as Bill does, get a wood block and drive the race flush, then use the ground down race, face to face on the new one to drive it to refusal in the bore.

Last I'll say about it - promise. Your boat, your rules.

[Starscream]

Job is done, for now.

Contrary to good advice I re-used the outer races in the three drums that I didn't replace.

Next year, I'll replace the brakes on the remaining three axles, so new bearings again. The bearings were not expensive, but the brake parts were. All the bearing, parts, grease, and a complete new brake assembly cost me under $200 cdn.

Bill and Jimmy, thanks for your good advice. Your instructions were very accurate, and good. I wonder how many mac-trailers actually get their bearings repacked every year, though. I'll definitely do it more frequently after this experience.

Old bearings, cleaned up a bit for inspection:



If anyone is motivated to do a bearing repack, don't underestimate the amount of grease needed...two full tubes worth, easy. And the number of rags, and gloves. And the amount of old grease that gets everywhere.

[Jimmyt]

I don't do mine every year.

Glad you got yours straightened out for the season. I know you're glad you had two axles. Makes me wonder about my single axle even more.

[Starscream]

Well, everything held together for the launch today. Bearings were all cool.

Our roads here in Quebec are like a continuous shaker-table test. I don't know why car companies spend so much money on proving grounds, they should just drive around our province instead.