Sudden Wheel Bearing Failure?

[Splitface2811]

I seem to have had a rather sudden front wheel bearing failure, for the second time.

The first time was maybe a year and half after a full swivel hub rebuild, so I assumed I didn't set the preload correctly and neglected to check the bearings frequently afterwards.

This time is about 500kms after a service where I checked the bearings for play and found none. The outer bearing is destroyed, as is the stub axle. The inner bearing is intact but is crunchy, so will be replaced as well. The bearing grease has also gone completely brown. I can't see evidence of water or mud getting in, other than the colour of the grease.

Both times, its been the left side (passenger in aus) that has failed in such a spectacular fashion. I haven't checked the other side yet this time, but last time it was quite loose and chewed up the stub axle, so I just replaced it all while I was in there.

What I'm wondering, is there anything else that might be damaged or worn out thats causing the wheel bearings to fail like this? So far I've been lucky and had these failures when I've been close to home, but I'd hate for it to happen in the middle of nowhere.

 

[Splitface2811]

Forget fish scales and forget torque wrenches.

Make sure the nuts and spindles have perfect smooth thread so the nuts can be turned with your fingers.

Tighten the inner nut with your fingers until there's no freeplay. Fit the lock tab washer.

Tighten the outer nut with about the same force as you would use for a wheel nut. This will push the inner nut in a bit more on its thread clearance and give the bearing slight preload.

Here's the important bit - go for a drive and feel the hub. You will feel slight warmth but it shouldn't be too hot to hold your hand on.

Alright, thanks for the info. I'll redo that to make sure.

I did check to see if the hub was getting hot and it was warm, but not uncomfortable to hold my hand on. I'd rather be on the safe side though. Thanks again.

 

[VPP]

On a full floating axle, this is a good method for adjusting wheel bearings:


1. Spin the wheel clockwise as you tighten the inner nut. This aligns the cup/cone and takes out the play as you rotate tire and tighten the nut.

2. As you spin the tire tighten the nut until it stops at the point where you would need to muscle it to tighten it further. Don't use a breaker bar for this wheel nut socket, a screwdriver works fine.

3. Using one of the hub studs, align it to the screwdriver or bar, then backoff nut counterclockwise to 1st stud or 1/6th.

4. Grab top and bottom of wheel and rock it for play, if there is no play install lock washer.

5. When installing lock washer, you may have to rotate nut to align with closets washer hole.

6. Install lock nut and tighten to specs. or until tight.

 

[mudgudgeon]

At this point my best guess is that I set the preload too tight and the heat caused it to fail.

Unlikely.

Many people have misread the FSM and tightened preload to 48ft/lb and then torqued down the lock nut to 48ft/lb and run bearings like this long term without issues.

The bearings in landcruiser hubs are huge in comparison to similar vehicles. Put them side by side with bearings in my F150, the landcruiser bearings are massive.
Big bearings are less likely to overheat, and will tolerate way more load including preload.

 

[mudgudgeon]

The way I understand it, the first torque is to seat it and then you back it off and retighten to set the preload.

Critical step here is to rotate the hub after the initial torque to seat the bearings.Torque to 20-30ft/lb (30 for big tires, or just go straight to 30)
Retorque to 30lb, rotate hub again.Repeat until you you're still at the 30lb preload torque setting after rotating the hub. Then installed lock tab, lock nut to 48lb etc

In the video above, the pounding on the sidewall is all about seating the tapered rollers in the conical race. Rotating the hub a few times with preload in the bearing is doing the same

 

[mudgudgeon]

I like to use the torque wrench methodbecause it's a recipe for a repeatable method that works. This is what the dish scale method tries to do, but it's not measuring a repeatable or critical metric.

Obviously there's other methods. I think the thing they have in common is an action to seat the tapered rollers, whether it's rotating the hub, or pounding on the tire

 

[MissahPapaJ]

Feel free to do what you will but the front wheel adjusting lock 9021542025 from Toyota is cheap enough to have a few extra on hand and in the rig, IMO the Toyota ones seem to have a little better build and deeper centering pin than some aftermarket stamps, I’d never pull a knuckle apart without replacing those with new ones ( keep the old ones bend them flat and throw them in the rig as spares ) most shops aren’t going to have the foresight to get new ones and they’re usually fairly bastardized or really cheap re-stamps by the time you get your hands in there.

 

[Godwin]

Feel free to do what you will but the front wheel adjusting lock 9021542025 from Toyota is cheap enough to have a few extra on hand and in the rig, IMO the Toyota ones seem to have a little better build and deeper centering pin than some aftermarket stamps, I’d never pull a knuckle apart without replacing those with new ones ( keep the old ones bend them flat and throw them in the rig as spares ) most shops aren’t going to have the foresight to get new ones and they’re usually fairly bastardized or really cheap re-stamps by the time you get your hands in there.

Agree. I've rebuilt a lot of hubs over the years, mini-truck, 40s, 60s, and 80s and often reused the washers and hub nuts. A few years ago I decided on one rebuild to replace all the parts with new and that, IMO, was a significant change toward proper torquing of wheel bearings. I prefer the OEM washers and nuts to aftermarket, Toyota stuff simply fits and works better.