[urq] Whining noise when cold (Hanger Bearing)

[fdekat]

HEllo James:

"Classic" sounds of a tired hanger bearing. 
Perhaps  sound that you hear when it gets going good almost sound sort of
'musical' with lots of harmonics, then as yuou say, jsut goes away after
running a bit..

Annoying, but I've had it going on for a long time before I replace mine, and
I've never heard of one having a catestrophic failure (yet!).


Direct replacement is a BMW part. I think I paid ~60.00 CDN for mine. (Search
the archives for the part number). 

I don't think it's possible to lubricate the hanger bearing. If so, you'd
probalby have to remove it. And if you are doing that, may as well replace
it!

When you go to remove it:  The bolts that hold it to the car go into captive
nuts that are in a sliding channel. Do all you can to have the nuts undo.
Soak them ahead of time (quite a bit!) with you favourite rust defeating
liquid. Maybe apply lots of heat too.

Problem is, you can't really grab the captive nut to stop it from turning, as
it's trapped in a sort of raceway.  Once they start spinning, you are
screwed. If you DO have to cut the heads of the bots off (as the nuts are
just spinning), you have to figure out how to hang the bearing again. 

While you CAN use normal bolts and nuts, you will find the there was a reason
that Audi did it the way they did!  Because of space constrainits, it's
almost impossible to fit in a normal nut behind the captive nut's 'raceway'.

Plan on repacking the front and rear CV joints with grease (maybe new CV
boots, too, if you can find a part number?), and maybe think about replacing
the U joint while you are in at the job.

Regards,

=Frank de Kat=



 
> Message: 1
> Date: Thu, 7 Apr 2005 21:32:05 +0100
> From: "James Howard" <spam.me1 at ntlworld.com>
> Subject: [urq] Whining noise when cold 
> To: <urq at audifans.com>
> 
> For the last 6 months on&off, I've noticed a whining noise from under the 
> car when moving off from cold.
> The noise only occurs if the car has been parked for at least a couple of 
> days. It sounds like it's coming from under the car somewhere around the 
> gearbox/driveshaft/rear diff.
> The pitch of the whine increases with road speed only and is not affected
> by 
> engine speed, or coasting with foot on clutch or in neutral, or applying 
> hand or foot brakes.
> It generally lasts for up to 1 mile and then suddenly dissapears (with an 
> obvious cut-off rather than fading out) - sometimes the increases in pitch 
> occur in distinct "steps" - like a bus or electric train changing gear, but

> the steps are not related to gear change.
> 
> Any ideas?
> 
> Thanks,
> 
> Jim.