From digest.v7.n304 Fri Sep 19 16:00:30 1997
Date: Fri, 19 Sep 1997 16:25:09 -0400 (EDT)
Subject: RE: <E30> Brake Rotors
In my opinion, it's not worth it to resurface rotors. If the rotor is
warped, which yours are not, the warp may be "removed" by resurfacing but
would probably soon return with the first hard stop. Apparently, the metal
undergoes some transformation during the initial warping process that leaves
it prone to re-warping.
It sounds as if you son's rotors are not warped but mererly have some surface
grooves. I'd take them to a reputable parts store and have the thickness of
each rotor measured; there is a minimally allowable thickness. It may be
stamped on the rotor; if not, the parts store should have a listing for the
minimal thickness. If the rotor(s) are close, replace them in pairs - both
front and/or both rear rotors.
Now, I have my flame suit on - buy the new rotors at the dealer! You'll find
them cheaper via mailorder but BMW OEM quality is tough to beat. I know -
I've ordered parts that were supposedly "OEM" and turned out to be junk!
Flame suit off.
If the rotors are well within spec, just remount them; the groves won't
affect braking performance. Do replace the socket head screw that holds the
rotor to the wheel bearing flange. Buy them at the dealer too Use
anti-sieze compound on the threads of these screws. Also, use lithium grease
on the hubs - where the center of the wheel mates with the hub. Since BMW
wheels are "hub centric," it's a very snug fit between the wheel and the hub.
Corrosion, however minor, will make the removal of the wheel a real bear.
Pads - Metalmasters pads are all I've used on my '85 325e (bought new). They
are noiseless, dustless (well, almost), warm quickly, and stop like the
Just my humble opinion, but I HTH.
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1985 325e, 141k miles and still pulls 88mph in 3rd gear!!!!