Pulsing f*cking brake rotors

[rumatt]

If I put race pads on the car, drive around for a while, and the vibration is gone then it blows a hole in the damaged caliper theory, right?

[FC]

Originally Posted by rumatt

If I put race pads on the car, drive around for a while, and the vibration is gone then it blows a hole in the damaged caliper theory, right?

EDIT: Yes, likely. But at that point I'd be out of ideas as to what is causing the issue. I am not an expert in braking systems at all. But here is my analysis nevertheless from what little I know.

The pulsating thing can only be caused by one of two things (as far as I can think of right now):

1. Something is causing you brakes to wear unevenly and and you are feeling the uneven surface as it comes around every revolution.

2. The hydraulic pressure itself is going up and down. I don't know enough to postulate a reasonable theory for this could happen, so I am gonna conveniently ignore this possibility.

So on to things that can warp your rotor:

A. Uneven wear due to uneven pressure as I explained on the post above.
B. Thermal shock if you splash your (VERY hot) rotors on a deep puddle.
C. Intermittently sticking capilers. Weird, and unlikely without you noticing something is really wrong.

[zach]

Originally Posted by rumatt

If I put race pads on the car, drive around for a while, and the vibration is gone then it blows a hole in the damaged caliper theory, right?

Hmm, I'm stumped.

[ff]

Originally Posted by rumatt

Does your certification allow you to drive to my house and fix my car?

I think it requires him to.

[rumatt]

Originally Posted by zach

Hmm, I'm stumped.

Well, I didn't do it yet, so....

[Josh (PA)]

Originally Posted by rumatt

If I put race pads on the car, drive around for a while, and the vibration is gone then it blows a hole in the damaged caliper theory, right?

depends how they heat up and how they are worn... ie: if they are significantly thinner than your current pads, they may not drag (or drag as much) and not cause the rotors to heat.

Does it do it all the time / everytime, or only after they warm up? Does it matter how hard you press the brakes (does it get worse if you press harder or does it only start after a certain amount of pressure)? Any residual vibration not under braking?

[rumatt]

Originally Posted by Josh (PA)

Does it do it all the time / everytime, or only after they warm up? Does it matter how hard you press the brakes (does it get worse if you press harder or does it only start after a certain amount of pressure)? Any residual vibration not under braking?

It's there all the time. Any speed, any pressure. But as you would expect, the vibrations are faster at higher speeds, and stronger under firm braking.

Braking hard at high speed sucks, and makes me curse at my rotors.

[Terri Kennedy]

Originally Posted by rumatt

It's there all the time. Any speed, any pressure. But as you would expect, the vibrations are faster at higher speeds, and stronger under firm braking.

Braking hard at high speed sucks, and makes me curse at my rotors.

I've had this forever. Dealer replaced rotors (and eventually calipers / mounting hardware) multiple times under new car warranty. Out of warranty, I tried various combinations of OEM / aftermarket rotors / calipers, and nothing fixes it 100%. I get the best results with Bavarian Autosport slotted + drilled rotors and OEM pads (had tried various aftermarket pads).

A good re-bedding clears the problem up for a while, then it comes back. So definitely not warpage - just some sort of build-up on the rotors.