Trailer Bearings

Interesting post. I've just completed a 4,000km trip over some rough roads in my "rough road" camper-trailer and the new bearings I had put in before the trip are fine.
However, better to be sure than sorry, so replace the bearings anyway. Make sure they are not overtightened - I check new bearings after an hour's drive by feeling the cap to make sure they aren't overheating.
It should prove interesting what condition your old bearings/shells are like when they come out and how much grease is left.
cheers
T.R.

Cram I think I would find a new mechanic, bearings don't develop flat spots if left just sitting.

Most bearing failure is from over heating (lack of grease, wrong grease or pre loading), wear or water getting in causing pitting.

With the three things listed above it comes down to maintenance and correct installation.

Bearings should last many years and thousands of K's if set up right but checking regularly is a good idea.

Regards Richard

Cram, one other point. If you don't know how to change bearing, you should learn. It is simple and the parts are not expensive.

If you do it yourself you won't mind the expense of doing them 'just in case'. It is a spare you should carry on long trips as well and knowing how to fit them if necessary would be handy.

The expense of failure at high speed in a remote area can be very high...... like the wheel coming off at highway speed.

I'm no expert (though I do change my own bearings', but in my experience if bearings are on the way out they will generate some heat. Take the trailer for a good run 20 km should be enough. Put your hand on the bearing cover and if it is too hot to keep it there for more than a few seconds, you have a problem. But I'm interested in the view of those with more experience than me on this.

Norm C

Hi cram,
how long is a piece of string? You have so many factors to consider.
In my opinion the no 1 killer of wheel bearings is not enough clearance (overtight), followed by lack of lubrication or overload. 1000km's doesn't sound like a lot of work for a off road trailer bearing so i'd be investigating the cause of the early failure. The flat spot your mechanic mentions would more likely apply to the tyres i think. mMaybe the seals are bad and you got water into the bearings, which would cause rust and pollute the lubricant.
My trailer has done about 14000km's and still has the first bearing sets.
Cheers, Udo

My Offroad bush trailer's bearings needed replacing after one season and about 20,000km. Both sides had the rollers pitted.

Looks like it might be an annual thing to replace. Around $36 for both wheels so it is cheap insurance.

Cheers

Hi Cram, Bearings are cheap, cheaper if you get them yourself, if your mech is as good as i think he is why would he diddle you out of 1- 2hours worth of work????

My best mate is a mech and he's told me once, told me a thousand times" Prevention is better then Fixing" so get the bearings replaced and carry not ONE set of Spares But Two!!!

You change one you change them both????
They shouldnt be too much down at the local bearing/ bolts/ engineering shop!!!

Oh happy travels

Hi Cram just while you are on this subject what do people think of those bearing buddies (spring loaded to keep feeding grease in, when right out pump in more grease). I have these on my 4x4 camper ?? Regards Steve M

While on the topic of packing bearings. i first learned to do this in the Army over 30 years ago. Apart from packing the bearing correctly, we used to fill the whole are with greas and also the cap before you put it on.

I undersand that is now regarded as old thinking or not necessary. If you use good grease and pack the bearing well, there is no need to fill the cap and everywhere else.

What is the modern (read newer than 30 years) thinking on this?
Norm C

I really don't understand why everybody seems so paranoid about trailer wheel bearings, in what way do they differ from normal vehicle front wheel bearings?
We do literally 10s of thousands of kms in our cars & vitually never give them a thought.
Maybe from new manufacturers buy cheap hubs with cheap bearings, but once they have been replaced with quality bearings it shouldn't be an issue.

I guess there is one way to fix the paranoia about not getting the grease correctly into the bearing and that is to change over to an oil hub bearing. With oil, the bearing always has lubrication.

Cheers,
Dion.

Hi Cram
On all my trailers I replace the bearings and seals every year and always carry spares.. Cheap insurance!
Nothing worse than having a bearing fail and an axle break miles from anywhere ( happened once on a campervan I had 25 years ago ).
Cheers Allan

As has been said three things will stuff the bearings, wrong grease, too tight and crook seals.
The correct grease to use is Castrol APX -T or similar in other brands NOT HTB (the trailer bearings never get hot enough to melt HTB so they only get the little bit packed in initially).
A tiny amount of freeplay is better than too tight.
Use the double lip rear seals that have a stainless bit that fits into the rear of the hub and use a small smear of silicone on the cap to seal the outside.
As has been said the same bearings on the front of a car will last the life of the car usually.
When I used to use the wrong grease (HTB) I'd be replacing the bearings after every trip, since using the APXT I have never had to replace a bearing and only repack about every 5 years or if a seal gets rock damage.
Another trick is to fit hubcaps if possible or make protectors to stop rocks knocking the outside cap off. If the cap is lost the bearings are toast very shortly after on dirt roads, dust and grease makes for great grinding paste.

The only problem with hub caps or similar is you can't see the tell tale signs of trouble when you get oily crap running outwards from the middle of the rim, which is a sure sign your bearings are about to chit themselves.

Assuming you have tapered roller bearings one thing that will cause "flat spots", more correctly called brinelling, is if the trailer has ever been transported over a long distance say on the back of a truck from one State to another from where it was manufactured to where it was sold, possibly prior to you taking delivery of the camper. This is problem with all equipment mounted on bearings when being transported and can only be avoided if the item being transported is supported with the weight off the bearings. What happens is the bearing rollers contact the cup and cone and the movement during transport can allow a wear pattern or "flat spots" to develop in one area due to the high point contact loading not being distributed over the bearing surface as happens in normal operation. Also the lubricant film breaks down it not being distributed by normal bearing rotation compounding the problem. If this is the case the bearings are virtually "stuffed" before the camper is put on the road and once it is put into service the wear pattern is already established and just goes from bad to worse. Other than that the bearings, assuming they are sized correctly for the load, should last for 100's of 1000km provided the correct lubricant is used, dirt and water is kept out and adjustment is correctly maintained. One thing to be careful of if fully packing the bearing cap and the void space in the hub between the bearings is that apart from a waste of money and serving no useful purpose (a smear over the surfaces will prevent any corrosion) in certain circumstances the grease can overheat and leak out over the brakes (if fitted) due to the internal friction of the grease churning around on itself. That is why bearing buddies are of little use except for short distance work with boat trailers where the bearings are being fully immersed in water. Regarding the comments that buddies push out the seal that can be overcome if the seal is installed back to front and dirt/water is kept out by the fact the space is kept full of grease.

Thanks for all the replies. You have all given me plenty to think about.

I have no issue that there may have been a problem with the bearings and that they may have been faulty but after being billed today I am mighty bleep off with the money I was charged to replace them.

So I will be taking all the advice on board and finding someone who can teach me how to replace, check, regrease etc.

Once again thanks for the comments.

We head off on Thursday morning for our trip.

My boat trailer bearings get checked every six month or prior to any big trip. To me it is simple and at least I know what the bearing are like. Always take two sets and they are in a PVC tube wrapped in a oiled rag to stop them rusting.

Has worked for me last 20 years.

Last Cape trip one of the trailers did his bearing they were brand new before the trip collasped with only 3000 k om them. They were done by the trailer mod he got the trailer from. He was not very happy ......... and we were in the middle of nowhere when it happened. I am please he had spares.

Brian