Replacing rotors on '93 90CS

[Mike Arman <armanmik@n-jcenter.com>]

>
>Date: Wed, 07 Jan 1998 15:08:22 -0500
>From: Elliott Potter <epotter@abraxis.com>
>Subject: Replacing rotors on '93 90CS
>
>I'm going to need to replace the rotors in the front and rear of my 90
>CS, but am having a little trouble figuring out exactly how (there's a
>first time for everything!)  Looking through the repair manual, there
>are detailed instructions on how to replace the pads, but none on how to
>take off the rotors.  I did, however, find some pictures in the axle
>assembly section that looked promising, but they seem a little too
>simple:
>
Yes, they are too simple. You're barking up the wrong tree.


>Front axles:  It looks as though there's a single bolt/washer that
>screws into the Axle shaft, through the wheel bearing and wheel hub. 
>Can this be correct?  One bolt?  Also, it says "loosen/tighten ONLY with
>vehicle on ground."  Well this just doesn't seem right--especially if it
>attaches the wheel to the axle!  How is one meant to support the car?

This nut secures the outer end of the drive shaft in the front hub. You
don't need (or want) to take it off to do brakes. Typically, the brake
caliper is bolted (two bolts) to a bracket which mounts on the steering
hub. Removing the two bolts allows you to swing the caliper clear of the
brake disk. The disk itself is indexed and aligned by the wheel bolts (or
studs), and held onto the hub by the wheel itself. When you remove the road
wheel and remove the brake pads, the disc is actually supposed to be loose
on the wheel hub, but may require a few taps to free up - it is usually
rusted in position, fortunately not tightly.

Same system applies to rear brakes. Always support the brake calipers -
don't let them hang by the hose - this twists the hose and can ruin it. Do
one wheel at a time. reason is that you will have to press the caliper
pistons back into the calipers so everything fits back together on
re-assembly, and if you have TWO calipers off, when you press on one, the
other pops out - makes a mess and you get to re-assemble and now bleed the
brakes (which you should do anyway, but on your own terms, not as an "oh
Sh*t!" task.)

Note that on some Audis you have to screw the rear caliper pistons back
into the caliper - you can't press them back in like the fronts - I'm sure
someone else on the list will advise.

>
>Rear axles:  This looks much more simple, though it is the same idea as
>the front (snip)

Best Regards,

Mike Arman