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From digest.v7.n165 Mon Aug 25 01:33:36 1997
From: "Duane C" <>
Date: Sun, 24 Aug 1997 22:54:09 -0400
Subject: E36 Brake Shudder

> I am experiencing brake shudder at high speeds, above 60mph.
> Below that speed, the brakes are fine. It happened after I installed
> 225/45ZR17 tires in front. I have sent the car for wheel balancing 3

> and it still happens. The mechanic told me the brake rotors need to be
> machined. Therefore I am thinking of installing cross-drilled rotors and
> stainless-steel braided lines on my car. Any experiences out there would

> appreciated. Thanks!
> Sincerely,
> Brandon Ong


Your 'mechanic' is all wet. Machining the rotors is only good for taking out
scoring, not warpage. Time for a new mechanic!

There are two causes for brake rotor warpage:

  1. They become too hot - usually this type of heat is only seen on the track. As yours is a cab., I'll assume you are not on the track. You will almost NEVER heat the rotors this hot on the street. You will know it because you can *smell* your brakes pads literally cooking.
  2. Wheel lug nuts are improperly torqued. You let the guys working on your car/changing tires use an air gun to tighten the lug nuts? Most air guns will spin at a range of 150 to 400 ft.lbs. Correct torque is 80 ft.lbs for your wheels. NEVER let anyone air gun your lug nuts. They should be installed by hand and hand torqued. Too much or uneven torque warps the rotors.
  3. Skip the cross drilled rotors...they are mainly for looks and will develop cracks where the holes are. Buy the Euro 2-piece rotor from Turner Motorsports. Same price as stock and will not overheat, but NOT available at your local dealer.
  4. If you replace the brake lines (which will do nothing else but give you a firmer pedal - that's all) then install Kevlar lines instead of stainless steel.

Hope that helps you out some.
Duane Collie
Nat. Cap. Chapter

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