Steve-l

Since I bought this truck new I have experienced heavy wear of the brake pads in the rear. I have 60k miles on the truck and I am still on the original front rotors and pads. I still have 50% of the front pads left. I am very easy on my brakes. On the rear however, I had to change the pads last year and they have worn out again along with the rear rotors. When I changed the pads last year I paid special attention to the sliding pins and rubbers. I used antisieze on the pins and the calipers slid easily. This year, when I changed the rotors, the calipers still slid easily, but the pistons on both rear calipers were very difficult to retract. When I disassembled the rotors and removed the pistons I found that the phenolic pistons had swollen and were severly galled binding then in the caliper bores causing them to continually drag on the rotors and not retract. I have ordered new rotors.

Has anyone else suffered the same problem? I suspect some sort of a compatibility problem between the phenolic material of the piston and the factory brake fluid.

.boB

I'm not sure of the exact reason, but one day my rear caliper decided not to release But the time I got home (about 3 miles), that brake was really smokin! It was well over 800*F. I replaced the pads, rotors, calipers, and all the hardware.

Steve-l

Bob,
Thanks for the reply. I assume you did not take your caliper apart. If you still have it, I would appreciate you doing so. My concern is that this problem is still very common. All plastics are hygroscopic to some degree and phenolics are no exception. When using this material, this natural absorbtion must be considered when determining the piston's running clearance. The reason the steel piston is coated with the plastic is to prevent bind from piston rust. My concern is that the caliper bore was manufactured without adequate clearance. I don't have great confidence my replacement calipers will be any better,especially now since your experience is with an '07 truck.