A problem I had a couple of years ago when I relined only the front brakes on my 98 3/4ton was that the friction material didn't match whatever is on the rear. So the front rotors would overheat under load and begin to pulse. I could feel it in the steering wheel and the brake pedal. It had new rotors. I put the original pads on the new rotors and the problem went away. I suppose I'll have to change the rear shoes when these pads wear out unless I can find the part number for the pads on it now.
The same thing happened on my 1-ton AD but for different reasons-- no cooling holes in the alloy wheels. New wheels fixed that.
Do you have any idea if the friction materials are compatalble front for rear?
