[200q20v] UFO brake pads - [long]

Gorman, Ken (PA62) ken.gorman at honeywell.com
Thu Mar 29 08:35:43 EST 2001

My first ever front brake pad replacement occurred last night on my 1991
Audi 200TQ.  It didn't go as smoothly as I had planned, but it's done now.
Here are the gory details:

Jacked up the car, put it on jack stands and removed both front tires.
Figuring out how to remove the clip that holds in the pad closest to the
piston took several minutes of me looking at it before I realized what to
do.  The backing plate of the pad had rusted itself to the piston, so I
needed a screwdriver to pry the pad off the piston.  I used an assortment of
tools to act as levers to push the piston back as far as it would go.  The
screw holding the UFO rotor was a Torx - and it was stripped - apparently,
during one of the previous brake jobs, someone must have used the wrong size
Torx and stripped it.  I had trouble finding a Torx screwdriver and spent
about 30 minutes scouring the house trying to find one.  When I finally did,
I managed to get the screw out.  My next problem was, I couldn't get the UFO
rotor off.  There didn't seem to be enough clearance.  It took some
fiddling, but I soon realized that I needed to push the piston in even
further.  The second pad came off easily, and then I noticed that the wires
on the sensor were frayed, but the pad still had a lot of meat left.  "I've
gotten this far - may as well put in the new pads" I thought.  I couldn't
figure out how to remove the old wiring harness.  After a few minutes, I
noticed a small metal clip holding the female connector onto the old frayed
male wiring harness.  I grabbed the clip with my pliers and pulled.  It came
off and went flying somewhere - I never did find it.  It took me a good 20
minutes to realize the frayed wiring harness connecter needed to be turned
1/4 turn and then could be removed from its mounting bracket.  Why isn't
this mentioned in the Bentley?

Once the one pad was in, I had a problem getting the UFO rotor back onto the
hub.  I wrestled with it - forced the piston back, and little by little, I
was able to coax it on.  A little more pushing the piston and the second pad
went in.  A few minutes figuring out the clip that holds the second pad in
place, and wham! - aside from putting the wheel back on, I'm done one side.
Total time - 2 1/2 hours for the first side.  

I'm really not that slow, but I did spent 30 minutes trying to find a Torx
screw driver.  A neighbor stopped by and we chatted for a while.  But, total
clock time was 2 1/2 hours.  I informed my wife of my success, and armed
with this new found knowledge, I boasted to her that I'd get done the other
side in 30 minutes - boy was I wrong.

My car has wheel locks with a keyed nut and a bolt that screws into the hub.
The bolt was rusted solidly into the hub.  The bolt is screwed into the hub
with an allen wrench fitting in the top of the bolt.  I couldn't get the
bolt unstuck.  I sprayed it liberally with wd40 - tapped it a few times -
let it soak for a few minutes - but no luck.  I heated it with a propane
torch - threw water on it - no luck.  I though the expansion and contraction
would free it up.  I ended up stripping the allen wrench fitting and still
no luck.  I got out a pair of vise grips and gripped the threads of the bolt
- without any luck.  It was now getting late.  I drove to Home Depot and
purchased a screw extraction kit and a can of Liquid Wrench.  Back home, I
had a difficult time trying to tap the bolt with the screw extraction taps.
The bolt is hardened steel.  I figured persistence would pay off.  My plan
of attack was to soak it in Liquid Wrench and WD40, let it penetrate, and
use the vise-grips with abandon.  After several rounds of this, the bolt
started to turn.  The rest of the job went by without a hitch.  It took
about 2 1/2 hours to unfreeze the bolt, and about 30 minutes to change the

The bolt is completely useless today, so I'll have to pick one up.  I'm
currently driving with only 4 bolts on the one side.

Total time: 5 1/2 hours.  
Lessons learned: many


Ken Gorman


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