UFO Rotors - $$

Bernie Benz b.benz at charter.net
Thu May 1 11:54:50 EDT 2003


IMO rotors, UFO or otherwise, should not be turned unless they are badly
warped, inasmuch as they tend to wear true and therefore used rotors will
always be better than new or machined, warpage not withstanding.  Some on
this list have talked about a "dewarping procedure" that they have used
sucessfully, but I've never had the problem so don't know about it.  Rust
does not contribute to warpage and should not affect the braking surface
unless the car has been parked below high tide elevation for the winter.

Measure the runout of each rotor, the max spec being <.002"  If you do not
have access to a dial indicator, A post-it is about .0025", so if stuck to
the low runout side of the outer breaking dia on the inboard rotor surface,
it should not go under a pointer fixed to just touch the high side of the
runout.  Simple test, I'll bet you'll find no runout problem.  Or, if
necessary, they can be shimmed into spec with paper shims at the hub
interface, BTDT on G60s.

But do overhaul your calipers and caliper slides!  A dirty but zero cost
job, and may well be the cause of your problem.


Bernie Benz
Gardnerville, NV

'90 90Q-20V  140K
'91 200Q-20V 140K
Ford "Quatro" Tractor
Other Misc. Toys
> From: "Tom Mullane" <tmullane at snet.net>
> Date: Thu, 1 May 2003 13:07:02 -0400
> To: <200q20v at audifans.com>
> Subject: UFO Rotors - $$
> This is a multi-part message in MIME format.
> --
> [ Picked text/plain from multipart/alternative ]
> My UFO rotors are suffering from Northeast rust syndrome, causing the brake
> pedal to pulsate.  The rotors on the car now are original equipment at 155K,
> so I have doubts about the feasibility of turning the rotors.  I also tend to
> be more of a "while I'm in there anyway I may as well..." preventative
> maintenance type of guy rather than a BFI if IAB guy.  So will I have decided
> to change both pads and rotors, and possibly rebuilding the calipers.
> After much deliberation, I have decided keep my existing UFO brakes rather
> than upgrading.  The factors influencing my decision included some uncertainty
> about the length of time that I will own the car, my choice not to use the car
> for any track events, and the fact I would like to be able to continue to run
> the stock wheels.  (I would like to do some track events, but I am hoping to
> acquire a 944 turbo at some point in the future for this purpose.)

> Anyhow, I was surprised at the price of the new UFO's (this was a large part
> of my choice to retain the UFO's).  Audi quoted me $272 each for
> new...surprisingly cheap.  Northside Imports in New Jersey (Bill Maas) quoted
> me $198 each for new.  I have dealt with Maas/Northside for years and I would
> imagine that their rotors will be identical to the Audi rotors.  Anyone have a
> problems with aftermarket versus dealer?  Anyone find a cheaper source for
> UFO's?
> TIA.
> Tom Mullane
> 91 200Q
> 91 CQ
> 99 A6Q
> etc.

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