Terry Adams

I had some small amount of vibration on braking last week. Yesterday I pressure washed the rotors, including rolling the car back a quarter turn to expose the holes hidden by the caliper. Vibration gone. Hope I did not blow a clip out.

Steve Weiner-Rennsport Systems

Hi:

This has been an interesting thread,.....

Might I offer that its really rare to see many warped rotors on these cars unless the car has been extensively tracked. Many brake vibration complaints are caused by uneven brake pad deposits on the rotor surfaces.

Before one condemns a set of rotors for replacement, do yourself a big favor here,......Have them checked for axial runout with a magnetically mounted dial indicator. If you find that the rotors are truly wobbling a bit: .006 or more, then by all means replace (never turn) them.

If they are not warped, briefly install another brand of pad and drive it hard for 50 miles or so to clean off the deposits.

Remember, the bigger the brakes (such as Big Reds), the greater the propensity for this to happen. Its triggered by insufficent brake pad temperatures.

campbesl

<Before one condemns a set of rotors for replacement, do yourself a big favor here,......Have them checked for axial runout with a magnetically mounted dial indicator. If you find that the rotors are truly wobbling a bit: .006 or more, then by all means replace (never turn) them.>

Steve,

Why do you say not to turn (machine) the brake rotors? From what I've seen in the shop manuals, Porsche approves of machining rotors.

TIA.

Scott

Steve Weiner-Rennsport Systems

Hi Scott:

There are several things that Porsche approves of that I do not agree with,....LOL,....Oil change intervals for one. Good for them; bad for you.

I've made it a practice to never machine (non full-floating) brake rotors that will be used for DE events or racing. Removing metal that reduces mass (therefore thermal dissipation capacity) will increase the likelihood of a warped rotor, especially street type ones. One can Blanchard grind a full floating rotor to its minimum thickness without an issue,....

Traffic53

thanks steve-
i haven't really seen any threads recommending machining rotors- i thought it sounded somewhat fishy

johnwelch

Just wanted to say a quick thanks to all, and also say that as this was well worth the price of admission I have just signed up for membership. Now, I'm just waiting for my membership number!