1998 Dodge Ram V8 Four Wheel Drive Automatic 128000 miles
About 2 months ago, I heard a sound coming from the rear of my truck, sort of a rubbing sound. I thought the brake shoes had worn out, as they have never been changed. Upon inspection, the rear wheel cylinders were leaking. I changed both rear cylinders and went ahead and changed rear shoes and bled the brakes. After driving the vehicle, I noticed the rear wheels getting hot. I took it to a service center and they said they were not hotter than normal, although I had my doubts. Later, I noticed that under hard braking, the rear brakes would lock and/or ABS would activate. I took it to a different service center and they said have the drums turned and install new shoes. When I pulled one of the brake shoe return springs off, the piston slowly pushed out of the brake cylinder bore. I deemed this abnormal, put the truck back together, and took it back to the same service center. They bled the brakes, installed the shoes, and gave it back to me. The brakes work fine, not locking in the rear now, but when I took the same return spring off, the piston still pushes out of the bore. I took it to a different shop. They said it was the master cylinder, as I was inclined to believe also. They changed the master cylinder and the rear rubber brake hose. The piston still pushes out of the brake cylinder bore when a brake shoe return spring is removed. This happens on both the right and left rear wheels. This can't be normal. The truck drives and brakes fine for now, but I believe if left as is, I will have further brake problems in the future. Anyone have a similar experience or advice? As a side note, I had to have the proportioning valve and ABS modulator replaced by the dealer about a year ago. I wonder if the problem somehow stems from these two components, as I don't know a whole lot about what problems they could create if faulty. Any ideas?