UFO tuning

[Eric_R_Kissell at whirlpool.com]

I think I was the guy who mentioned de-shuddering the UFO's on the eBay
prize 1991 200q 20v Avant on my trip home from Baltimore to Indiana.

Whenever I have brake disk that shudder due to warpage I like to get them
really really hot and then let them cool while rotating without touching
the pads to the disk while they cool.  I usually do some rapid
decelerations from as fast as I can down to as slow as I can without having
to stop anytime soon after the deceleration event.  Three or four heat
cycles usually relieves the uneven stress distribution that has caused the
warp.

I also like to bed my new pads with the same procedure to outgas them, but
that really has nothing to do with disk warping.

This de-warping has worked for me on my 10V turbo Type 44's with G60's and
now on the eBay prize 20V with UFO's.

As far as preventive actions to prevent warpage, I try to avoid getting the
brakes really hot and then sitting with the brakes applied.  My belief is
that if the pads sit on hot rotors in one place for long enough, then the
rotor cools unevenly and warps.  So, if I am running between stoplights for
a stretch, I tend to slow down somewhat relaxed over a longer distance to
reduce heat generation.  After all, I have to wait at the next light
because it will be red anyway, so why warp my brakes with an unnecessarily
abrupt stop.  Then once I stop I try to not hold the brakes applied at one
spot on the disk if I can avoid it.

YMMV,
Eric Kissell
1991 200q 20V Avant, eBay Prize
1989 200q Avant, 1.8 Bar (qlcc)
1986 5000cstq, 1.8 Bar (SJM), Bilsteins
1987 VW GTI 16V, 1984cc