The brake story: frequent disk warpage

[CoryM]

Hi Lux,

It may be as simple as a minor adjustment to your driving. Think about racecars: You often see them with glowing steel rotors, yet no pulsation. If heat alone were the cause that wouldn't be the case. Where the problem comes is when they cool down. If you get the rotors hot, then stay at a complete standstill with your foot on the brake, the area underneath the pads cools down slower. This makes that area different thickness than the other areas, and the pedal pulsate. The reason you only see it after heavy braking is because you need to get the rotors up to a certain temp to affect the grain of the steel. So you need to either keep the rotors below that temp, or cool them down evenly.

Fixes:

- instead of staying on the brakes steady down a hill, release them occasionally. They will cool down a LOT in the second or two you release.
-always come nearly to a stop, and then let your car roll for the last few feet. Let the rotors cool down below the critical temp before sitting there stopped with foot on brake.
-if your rotors are hot, but you still need to hold the vehicle at the light etc, use the park brake for a few seconds. Rear brakes do not get nearly as hot as front and are much less likely to warp.
-make sure your rear brakes are adjusted correctly. Otherwise the fronts end up doing all the work.

I have never warped a rotor, and definitely not because I brake gently. I brake hard (I even drive on R-comp tires and can brake much harder then street tires), but I don't let the rotor cool down at different rates. I'm also from BC..... our hills are the size of your mountains

Cheers.

[eseibel67]

Originally Posted by CoryM

Hi Lux,

It may be as simple as a minor adjustment to your driving. Think about racecars: You often see them with glowing steel rotors, yet no pulsation. If heat alone were the cause that wouldn't be the case. Where the problem comes is when they cool down. If you get the rotors hot, then stay at a complete standstill with your foot on the brake, the area underneath the pads cools down slower. This makes that area different thickness than the other areas, and the pedal pulsate. The reason you only see it after heavy braking is because you need to get the rotors up to a certain temp to affect the grain of the steel. So you need to either keep the rotors below that temp, or cool them down evenly.

Fixes:

- instead of staying on the brakes steady down a hill, release them occasionally. They will cool down a LOT in the second or two you release.
-always come nearly to a stop, and then let your car roll for the last few feet. Let the rotors cool down below the critical temp before sitting there stopped with foot on brake.
-if your rotors are hot, but you still need to hold the vehicle at the light etc, use the park brake for a few seconds. Rear brakes do not get nearly as hot as front and are much less likely to warp.
-make sure your rear brakes are adjusted correctly. Otherwise the fronts end up doing all the work.

I have never warped a rotor, and definitely not because I brake gently. I brake hard (I even drive on R-comp tires and can brake much harder then street tires), but I don't let the rotor cool down at different rates. I'm also from BC..... our hills are the size of your mountains

Cheers.

This is great advice. I use my brakes HARD, yet I've never warped a rotor and the friction lasts a very, very long time. Proper lube and cooling are the key. The absolutely worst thing you can do is hard stop to a complete rest and then stand on the pedal against a smokin' hot rotor.

The only other thing I would add to above post is that it's a good idea to "bed in" a new set of pads. Google the procedure.