Canada Panda wrote:Is there a grinding noise as the brake pedal pulsates and are the pulsations very quick (more than 30 times a second)? If the pulsations are slower, closer to 2-3 times a second, you are likely feeling a "warped" brake disc.
If it is an ABS issue, take a look at the wheel sensor tone rings. Close to the hub, you will see a ring that looks like a square-tooth gear, but it is not driving anything. That's the tone ring and they are prone to crack, especially if you have cold winters. Some people, myself included, have had success in repairing cracked rings with some JB Weld. I think the full repair involved replacing the driveshaft as the ring is pressed on.
If you are just feeling a warped brake disc, try using a wire wheel to scuff up the disc surface and then do a burnishing process on your brake pads. This involves finding a deserted stretch of road and braking from 30 MPH to 5 MPH ten times, followed by a half mile cooldown drive, followed by braking from 50 MPH to 5 MPH five times. Braking should be firm and constant in pressure, but not as hard as in emergency braking. This will deposit an even layer of friction material around the disc. Most "warped" discs are not warped due to the metal deforming, but rather from uneven deposits of friction material on the disc surface.
reply; No grinding noise,more like a clicking noise. Pulsations are more like 2-3 @sec. I did not have discs reground when I changed the pads. They were done before and I did not want to chance removing too much mat'l. There was a small wear step from the old pads which I removed before putting new pads on.
I will try your rapid stop procedure as soon as I get a chance. Will let you know results. Might have to re-grind /or replace discs in the end.