| I posted below about a seeming brake drag issue I have been having after rebuilding rear calipers and replacing parking brake, brake lines and rotors. The consensus seemed to be a caliper or brake pad issue possibly caused by grease applied to the caliper dust boots. I removed those and cleaned and reinstalled. I also double checked the parking brake adjustment. The "dragging" seems to be gone especially with any in-city driving but my rear rotors still get really hot after 30 min. of interstate driving and then the drag can sometimes appear, just not nearly as bad. I've recorded temps over 400° at times on the rotors. Fronts are usually around 110 to 120 with no issues.
After several disassemblies and reinstallations with not much changing, I took the car to CarX to have them inspect everything about the rear brakes. They had the car for most of the day. They removed the calipers, checked for parking drag and pad installation. The only thing they could find was that the left inner piston seemed to be sticking a little. (would BOTH rear wheels be affected by a sticking caliper on one wheel?)
I took it home and removed the caliper and piston. I could see on the bench it did not slide as easy as the outside piston when using compressed air. There appeared to be a little discoloration on a little part of it and in the cylinder that didn't just swipe off so I used a dremel with a polish tool to remove it on the piston and the cylinder. After that it slid easier. I could easily push both pistons into the cylinder by hand. Blast of air at less than 20 psi and they would pop out. Stop air and you could see them retract a bit. Reinstalled it and went for about a 20 minute drive of stop and go. Car drove fine and would still roll in neutral even on a very slight incline at the end of the drive, yet temps rose to about 150 to 160. Drove it 45 min. to work on the interstate the next day and the temps were 400+ and starting to drag just a little! Drove it home and the temps didn't get as hot but were still between 260 and 310 on the rotors. Wheels too hot to touch. Fronts still around 110. I'm at a loss. One thing I noticed when I was examining the parking brake and the wheels and rotors were off the car so there was no chance of brake drag, was that the rear wheels were difficult to spin by hand. They would go maybe a quarter turn. The same thing would happen when I had the tires on. I could not get them to easily spin more than 1/3 to 1/2 revolution. The front tires spin very easily but I know they don't have a LSD between them. Again, I don't know what amount of spin is normal for these rear tires? I gave the tires a tug left and right and up and down and both felt very solid, but I wondered if both wheel bearings had become toast from excessive heat and could now be generating heat... seems pretty unlikely but I am at a loss at what to try next. Any suggestions or troubleshooting steps on the brakes bearings or anything else are appreciated!
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