Hub flange failure - diagnosis, engineering chums?

I removed the track car driveshaft from the OSF hub the other day, only to watch the brake disc drop from centre

Cue disassembly!







Any thoughts on cause? The CV splines held the joint, so any rubbing / agitation has been minimal, and the CV nut was tight.

 

Certainly an odd failure. I taking a shot in the dark at it being wheelbearing related, either its the wrong one or its faulty. The flange normally has to be pressed into the bearing and they dont normally come out without a fight

 

Unusual that.
If the wheel bearings fail the flange can get a hard time and mark up the part of the flange that is located in the wheel bearings.

As it was the OSF I suspect it is down to the excessively heavy 16v engine, and a fat driver with weighty shoes!

 

To remove it, I've had to press the bearing out, and it was reasonably tight in the hub.

Of course, it may well be due to the engine installed, but ignore the fractional weight difference: it'll be due to the sheer 16v powarr Shoes are at homologated weight, unlike Dave's specials!

 

Could be a fracture caused by hammering the hub in opposed to pressing it in during initial assembly way back when. I have seen a similar failure on a mk3 vr6 when excessive bashing was used to fit the hub.

Gurds

 

Standard type fretting fatigue failure. Cause? 99.9% sure it was because the hub was not pressed fully up to the face of the bearing inner race.



When assembling an old hub, polish the surface with 1200 or 1500 grade abrasive paper. Polish up with Solvo Autosol. Use Rocal Anti-Scuffing paste. Make sure the hub is pressed fully home. Support inner race only, when pressing in hub.

 

Thank you Dave! A drawing just for me

It's gone just after the radius.

I press these bearings myself, so I can take the blame!

 

Nice drawings there , seems like the best most logical explanation.

 

Yeah I'd go for a garage in the past using a hammer to get it out rather than using the press method, I've seen so many hubs absolutely mangled because people think it's acceptable to bash then f%ck out of them with a hammer.

 

So, are you saying that Mr. Eyre hammered them out, and hammered them back, mangleing them in the process?

 

I would be wary of using the same outer cv again.
The flange looks like it has fractured at a point which would still have the cvs splines offering some support. It may have worn the splines to the point where fitting another flange to it will still have some play.
How tight was the driveshaft nut? It should hold and support everything together.

 

I belive Chris said the nut was tight Danny. What would happen I believe, is:

If the bearing is not seated, to the shoulder of the hub, then, as the nut was tightened, the interference fit, between bearing and hub, would take the nut torque but not move the bearing on the hub shaft. As fretting occured, the material would break, but the actual distance between the two broken parts, would be still zero mm. So, it would not be loose, but the hub would still be in two parts. Visual spline damaged would be minimal, but, actual damage would be of a similer nature due to fretting between the broken parts of hub and the CV spline.

 

So bin the CV all the same?

 

Yes Chris. Things will have happened inside the spline that may lead to early failure. The hub breakage is fairly fail-safe. But a CV splined shaft breakage could mean the drive shaft falls and jams everything up. Dangerous!

 

Proper tight,or southern shandy drinkin eel muncher tight?

But the nut only pulls the two inner races of the wheel bearing together. The outer race is fitted against a shoulder then the retaining circlip installed to keep it in position.


I would bin the cv joint as it is not worth the hassle of damaging another flange or wheel bearing. It must have had some wear on it from being used in this condition. Pity you are so far away as there must be a dozen mk1 hubs lying under my workbench.

 

Are they split inner races Danny? I had assumed that they would be solid races as below!

 

LOL!

 

Newcastle Brown, Raoul Moat tight

 

We all ought to have a trip to TSC Island and see who can pull the 80 lb bow!

I CAN!

 

They are split races Daved.
You always get the joy of carefully removing the one that stays on the drive flange when doing a wheel bearing!

Chris does not in this case.