Printable Version of Topic

Posted by: MikeM Aug 6 2014, 11:58 AM

Hi all...I think I might have a bent rear hub.I'm still chasing a vibration.
Is it possible to remove the hub with the trailing arm attached to the car?
I guess it could also be a wheel bearing...thinking out loud. The axle doesn't seem to spin true and I think I can see a wobble in the hub. The axles and CV joints are new from Tangerine.
Thanks,
Mike

Posted by: ThePaintedMan Aug 6 2014, 12:13 PM

Mike,
Have you verified the torque on the hub nut first? Should be ~220-250 ft-lbs. This should also ensure that the hub is seated fully into the bearing. If someone has messed with it recently it's possible it didn't get seated or torqued all the way.
If it is a wheel bearing you'd likely hear it. A growl or even a high pitched whine are both symptoms.
If you're going through the trouble of removing the hub, you might as well do the bearing too. The way I did it on mine with the trailing arm still attached means that the bearing will definitely be trashed... but at least it didn't have to be re-aligned.

If you want to see how I did it (the redneck way without a press), the link is in my signature in my build thread. It's toward the back.

Posted by: MikeM Aug 6 2014, 12:37 PM

Thanks for the reply. I just had the back end all apart replacing axles and cv joints.
I tightened the big nut as tight as I could with a large bar. That didn't fix my vibration so today I took the wheels off along with the left caliper and rotor. It still looks like something is wobbling, the axle is not spinning true. I think the hub might be bent but it's so hard to tell. I replaced that rear bearing 2 years ago. Maybe it's not seated right? No noise from the bearing.
Mike

Posted by: HalfMoon Aug 6 2014, 02:16 PM

QUOTE(MikeM @ Aug 6 2014, 02:37 PM)

Posted by: Cap'n Krusty Aug 6 2014, 02:52 PM

I suppose you could have a bent hub, but it'd take a pretty substantial whack to do that. If you remove the hub, you have to replace the bearing. If the bearing doesn't come apart when you press the hub out, the hub is worn on the surface that contacts the bearing and it's scrap metal. Before I pulled the stub axle and the hub, I'd put a dial indicator on it and check for out of round and wobble. That could be done with the disc in place "IF" the disc were secured to the hub with 4 nuts.

The Cap'n

Posted by: MikeM Aug 6 2014, 03:22 PM

I realize it seems unlikely, but there is a slight wobble in the axle for sure. I'm running the car with the rear end on stands. It's hard to tell where the wobble is coming from as the spinning sets up optical illusions...sort of. Again, just installed new axles and cv joints from Tangerine which didn't cure my vibration.
Mike

Posted by: ThePaintedMan Aug 6 2014, 03:55 PM

with Cap'n. You'd think that bending the hub would require an impact by a curb or another vehicle, but by that point you'd have other issues.

I think it's still possible that it never seated right when you did the bearing awhile back. Maybe it got crooked in the race or something is keeping it from sitting all the way flush.

Or sumthin else I guess the best way to start is by doing what the Cap'n suggested and use a dial indicator to measure runout. That way you can definitively say it has something to do with the hub and/or bearing before spending the money on a bearing, hub, or both.

Posted by: MikeM Aug 6 2014, 04:06 PM

This is good....I'll try to scrape up a dial indicator.
I can actually see the axle wobble...
As the Captain suggested, I'll have to make sure the rotor is secure.
Mike

Posted by: Porsche930dude Aug 6 2014, 07:57 PM

check it without the rotor on to rule that out aswell. make sure the surfaces are clean and your rotor is sitting flat. I swapped out my hubs without killing the bearings. and they were probrobly never apart. so there is hope.

Posted by: MikeM Aug 6 2014, 09:13 PM

Yes...I will look at it with and without the rotor.
There is a wobble, just don't know if it's enough to cause a vibration!!
Thanks,

Posted by: MikeM Aug 7 2014, 05:34 PM

I'm going to try to loosen the big nut and then re-torque it to see if it will seat everything properly. Sound reasonable?
Mike