Grease leaking from the hub drive boot

**Veek** · 12-11-06, 07:27 AM

After a lengthy run today, I noticed what appears to be bearing grease seeping from under the driveshaft boot on my right rear upright. The clamp is not adjustable so I was reluctant to peek. Has anyone repacked the rear wheel bearing and can tell me if there is a wheel bearing seal on both sides? If so, do you have the size so I can order it and any tips on replacing it? The seepage isn't too bad so I don't want to pull it apart until I have the kit to complete the job.

Canuk40 · 12-11-06, 12:07 PM

Hi Veek,

The bearings are sealed on both sides, the CV joint boot seals the axle to the output (splined) side of the joint. In theory of course nothing should be leaking. What you're probably seeing is grease from the cv joint not wheel bearing.

If there's no play in the rear wheel your bearing is probably ok. If it's got any play or roughness in it's rotation then it's suspect too.

Most likely the CV boot is not adequately sealing, you might get away with replacing the clamps with the car together. Otherwise the axles have to come off and to service the wheel bearings the rear uprights have to come off.

Note: Whether you're servicing the car or building up your rolling chassis, it's extremely important not to roll the car around on it's wheels without the rear axles in place to prevent the two bearing races of the rear bearing assembly from walking away from each other. This will give you slop that won't press back together. The hub will have to be completely pressed out of the bearing and reinstalled to close the tolerances up. Trust me on this one.

If the axles are out of the car and you have to put it back on it's wheels then at least use at least a .500/20 nut & bolt and some big washers to clamp the hub to the inner bearing race to keep them together.

If you get stuck anywhere give me a call on the toll free tech line.

Cheers

**Veek** · 12-12-06, 07:29 AM

Thanks Ian,

I'll pull the boot and see what I have there. The fact that I can slide the boot around with my hand suggests a bad clamp and maybe I'll get lucky with that being all there is.
Is there any special way to check the bearing other than jacking it up and checking for any movement with a good shake?

As always, thanks for the help!

Canuk40 · 12-12-06, 11:10 AM

Hi Veek,

There should be no noticable end play in the bearing, so if you get any the bearing is not to spec. It may not be toast, just not set. I don't know if you can buy the bearing from SKF in the states, it's not available from BMW here without the hub assembly. We bring them in from Europe.

Good luck and give me a call if you get stuck.

Cheers