Changing Trailer Wheel Bearings

graham

graham

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The bearings on our small boat trailer are getting a bit noisy so will be changing this week.

I last did this job about 15 yrs ago on a different trailer.Can anyone give me any tips on best way to do it.
 
Rather depends on the bearing type.

Tapered rollers .. easy inner races fall out leaving the outer races and the oil seal to be knocked out.
Clean out all old grease, fit the new outer races knocking them in squarely and fully using a brass or copper drift.
Grease the rollers and no more than half fill the space that will be left between them with grease Fit new seal after fitting the new inboard bearing. Fit hub to axle, fit new outboard bearing assy, fit thrust washer and nut. Tighten firmly while turning hub to bed bearings in properly. Back off and tighten as tight as you can with just fingers**. Stake /fit split pin as appropriate.

Much the same with ball races but the bearings have to be removed and fitted complete and with the spacer between them ... dont forget the spacer! Tighten nut fully and stake or pin

** expect this will be criticised but i have found it a reliable way of getting them just tight enough but not too tight.

One piece bearings I have never chaged but i have instructions if necessary.

Proprietary assemblies used by some trailer makers see their instructions ... website.

About half fill the cap with grease before fitting it.

Dont over fill with grease. It overheats and goes all runny if you do.
 
Pretty straightforward. Remove hub and races, may have to prise out grease seal on inner bearing. Clean out with a rag so you can see the cast spacer in the middle of the hub casting. There will be two small indentations in the casting which you can put a drift(punch) in to engage on the inner side of the bearing track and tap out the track alternating between the indentations to slide the track out smoothly. Once they are both out (turn hub over to do the other) clean up and put the new tracks in using either a large socket the same size as the tracks and a vice to press it, or very gently tapping with a hammer (on the socket, not the track). Or if you have a soft drift (brass or bronze) tap it in, going round the edges, to work it down level. Be pretty careful as you don't want to chip the track or jam it.
If there was a loose spacer between the bearings don't forget to put it in when re-assembling. Don't overload with grease. Enough to fill the roller cages should do.

That's how I do it. I await others' methods with interest.
 
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Fit my post and lakey's post together and you just about have it for tapered rollers or ball races.
The bits I missed out he covered and vice versa I think.
 
VicS said:
** expect this will be criticised but i have found it a reliable way of getting them just tight enough but not too tight.



About half fill the cap with grease before fitting it.

Dont over fill with grease. It overheats and goes all runny if you do.
Click to expand...

Couple of points. taper roller

Before fitting bearings, place inner race in the outer, get your grease and put a lump on your finger, push it into the gap were the rollers are large diameter end. Continue working grease in till it appears the other side of the roller cage, small end, you now have grease all through the rollers. This is actually all the grease you need, but it worries people, so a little between the brearing on assembly and a bit in the cap.

Assemble bearing as said, hand fit the nut till it is near the bearing, fit spanner, then rotate the hub with one hand while tightening the nut with the spanner. This will bed in the bearing, at some point the spanner will go hard up, NOT a lot force thought, back off 1 - 1 1/2 flats to locate split pin.

Easier to say than write.

Ball bearing may be angular contact, these came in just before I gave up designing axles, but they need to be set to a torque, this will come from the axle maker. This torque preload allows the bearing to carry the load, plus side loading.


Brian
 
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I reckon backing off a taper roller bearing 1 to 1½ flats is too much.

Angular contact ball races ... I hope not. I have those (Mini Rear wheel hubs) on my boat trailer.
Great difficulty finding them now and when I did they made gold bars look cheap.
Thanks to Lakesailor I now know I can get taper roller kits for a fraction of the price ( they are for mini Coopers but fit)
Mine were tightened fully against a spacer just like ordinary ballraces. (have instructions from Mini manual)

Worst I ever did were the rear wheel bearings on a P6 Rover. Taper rollers but pre-loaded by tightening on a compressible spacer. I dont know how many elephants it needed to compress the new spacer but I couldn't do it. Just fitted the old one and gently nipped them up in the end!
 
VicS said:
I reckon backing off a taper roller bearing 1 to 1½ flats is too much.
Click to expand...

If you rotate the hub as you tighten, then back off, it is normally OK, but the same as everthing, it's all in the original design.

If the nut is to tight, it will cause problems as the hub heats up by loading the bearing.

Brian
 
VicS said:
I
Worst I ever did were the rear wheel bearings on a P6 Rover. Taper rollers but pre-loaded by tightening on a compressible spacer. I dont know how many elephants it needed to compress the new spacer but I couldn't do it. Just fitted the old one and gently nipped them up in the end!
Click to expand...

Ever done the front bearings on a 2CV? I don't have my manual here, but it's a ludicrous torque - 300+ lbf-ft, as I recall. Getting them undone is the real fun ...
 
halcyon said:
Assemble bearing as said, hand fit the nut till it is near the bearing, fit spanner, then rotate the hub with one hand while tightening the nut with the spanner. This will bed in the bearing, at some point the spanner will go hard up, NOT a lot force thought, back off 1 - 1 1/2 flats to locate split pin.
Click to expand...

For the ones I know best - Triumph Herald front - the Approved Method is to tighten up till the wheel just locks (or there is significant resistance), back off a couple of flats, mark that point, undo, pack with grease and redo to the same point - making sure that you're not a full turn out.

It's all too easy to tighten when packed and find that it slackens off within a few hundred yards as the grease squishes around.
 
Ever done the front bearings on a 2CV?
Click to expand...
No but failed to get the nut undone on the front of Pug106 . One of those times when I have had to go to a garage!

Being an ex 2CV man you'll like this photo. Belongs to someone who lays his boat up in the same yard. I'll let you figure out what it is!

. . . .​
 
Go to YouTube and search for 'changing trailer wheel bearings'. You'll get lots of videos giving advice on how to do this for all types of trailer.

Regards
Harry
 
VicS said:
No but failed to get the nut undone on the front of Pug106 . One of those times when I have had to go to a garage!
Click to expand...

The only nuts which have ever defeated me have been a couple of crankshaft pulley ones - and in both cases a quick whizz from the air wrench at my local tyre place sorted them. Memo to self: get that compressed wired and plumbed in. It's been sitting there for eight years.

Being an ex 2CV man you'll like this photo. Belongs to someone who lays his boat up in the same yard. I'll let you figure out what it is!
Click to expand...

A Lomax of some sort? And I wish I was an ex-2CV man ... it's sitting on my driveway, looking for a home. Quite good nick, too - really just needs a respray. Anyone?
 
Thanks for all replies

Thanks for all the replies.Will be changing them this week hoping to go sailing next week if the sea doesnt freeze over in the meantime :-).
 
Some of the more recent trailers I have looked at use sealed double bearings. The torque setting is around 150 ft/lbs or more.Press needed to change them. Plus the nut size is a bit bigger than most socket sets, had to make the socket last time. And the bearings were €60 each. I use a Seat based trailer for my Oughtred boat, but am very carefull not to put the drums into the water. Also I was not impressed by seals running on steel bushes, which, of course, rusted and chewed out the seals, followed by bearing failure. Made by Roca, quite a big name here.
A
 
On trbs, as others have advised, a common problem is overgreasing. If you push grease from back face (large end), with cup (outer) in position, until grease appears at front face, then I think you are at risk of over greasing. Generally, if you have 'over-done' it the surplus will be pumped out at the front face due to internal pressures but there's a risk. It's worth reinforcing that when you tighten trbs you have to ensure the bearing is fully bedded and this needs the wheel to be spun not just rotated as you tighten. (The problem is that over-greasing can prevent sufficient roller-rib contact which results in excessive end play under load). When tightening try to just take out the end play without inducing pre-load. As the bearing heats up it will expand and give a little internal loading which is good for the application and bearing life. Getting it 'just right' needs a little care - at least limit any end play to not more than 0.005 thou (in old money).
 
Done them today.

Popped into our local trailer shop to buy bearings. They suggested that for very little extra money I could get a new hub complete with bearings.So thats what i did.

All went on well.Its only now as we roll down the road silently that i realize how ropy the old bearings must have been.

Thanks for all the advice. Much appreciated.
 
That's a good option. I've done that in the past and renewed the bearings in the old hub as well. Then you have a spare for those occasions when you are not near a dealer (so long as you keep it in your Towing Kit).
 
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