jrf1car

I have had to replace rear brake rotors 4 times in 75,000km due to bad vibrations under braking. The original equipment brakes are made of very poor material and rust very quickly.
Today I put on Stop Tech rotors with new pads and the vibrations are worde.
I am beginning to think there is a problem with the active diff and not just the brakes.
Anyone else had these problems?

superswiss

All brake rotors rust if they are exposed to heavy corrosives such as winter salt. Rotors are made out of cast iron. Spray them off frequently while they are cold. Spraying off a hot rotor can warp them.

Do you get vibrations while braking or also while not braking. The diff wouldn't cause vibration during braking. It's more likely that you have debris (rust) between the hub and the rotor, so the rotor isn't sitting flush on the hub and has lateral runout causing vibration. Given that you have a rust problem, I'm guessing your hub is rusted, too.

Bobby Kinstle

I had that problem with stoptech's ceramic pads. Now I run stoptech rotors on OEM pads and other than the dust, I'm very happy with them.

DrGP

I have Stoptech ceramics front and rear. OEM rotors. Don't suffer the same issue and have no dust.

Evan's Santorin S4

Have you tried swapping your wheels front to rear to see if anything changes?