I have a rear brake issue with my 2007 MT V6 Accord Coupe. At about 32k miles the front pads imprinted on the rotors which caused a mild vibration when braking. The pads still had about 6mm of friction material left but I replaced both rotors and installed new pads. These pads and rotors are still on the car, have about 5mm left and work great. I’ve replaced the brake fluid religiously, every three years and have only 70k miles on the car with a mix of highway trips and stop and go urban driving. With my last rear pad change, the driver’s side had 5mm remaining after 12k miles, but inner and outer pads on the passenger side were each down to 2.5mm, which surprised me. The caliper slide pins are lubed with Sil-Glyde and move smoothly. The pad ears moved easily in the guides but I did notice that the piston on the passenger side required significantly more force to rewind into the caliper. It did not feel gritty and there was no variability in the effort required, just harder to turn. When retracted, the piston boot looked fine and the new pads went in OK. I installed my first set of new rear rotors and after a few hundred miles, they are showing the normal swept area on both sides of the car. Pedal feels firm under braking and the car will roll freely when I take my foot off the pedal. The parking brake works on both rear wheels and releases fine. New calipers are awfully expensive and I don’t trust third party rebuilds. Now that I’m retired and driving less than 4,000 miles a year, I am tempted to just keep an eye on the wear and change out the passenger side pads if they continue to wear quicker. I have a second set of pads ready to do this. It’s a manual transmission car, so it is apparent that the car rolls freely when my foot comes off the brake at an intersection with any sort of grade and there is a slight slope to my driveway, so the car rolls as soon as I release the parking brake. My main concern is that the rear passenger side pads will at some point, fail to release or will provide ineffective braking. Any thoughts about the cause or alternate solutions?

 

You could just get a good set of calipers from the pick-and-pull and use them. They can be had cheap and usually work with no problems.

 

A little brake fluid on the piston itself (under the rubber boot) might help.

 

The car is nearly 12 years old, so I'm concerned about installing used parts. I've flushed the brake fluid every three years and only put 70k miles on the car. Most used calipers are going to have much higher mileage and most likely never had the brake fluid changed. The likely reasons for the piston to be hard to rewind back into the cylinder would be the surface of the piston or a swollen seal. I suppose the portion of the piston that was out past the seal likely had dried brake fluid or some other gunk on it, so the suggestion to put some brake fluid under the rubber boot might have lubed things up a bit before winding it back in. First thing I'll try is to rotate the piston out most of the way, push back the boot, inspect the surface, introduce some fresh brake fluid and screw it in and out a few times. Won't have to crack any brake lines to do this, so it would be any easy thing to try. Next step would be to unwind it all the way so the piston comes out, clean the piston if it's not corroded and then replace the seal. Due for another brake fluid change in a year, so I'd just do that early. Again, everything is working properly right now so I'm just trying to avoid premature wear of the pads again. Only evidence I have to go on is that the piston was harder to wind back into the cylinder on the side with premature wear. Could be some other reason I suppose.

 

Going by what your describing it does sound like a possible caliper issue and gently working the piston in and out as you generously mist the boot with some silicon spray can help just be very careful not to allow the piston to come to far out or risk ruining the seal and having to replace that caliper. Also although your ebrake is engaging and seems to be releasing under the weight of the car to roll doesn’t mean the arm on the caliper where the cable attaches isn’t sticking or binding/ causing more pad wear through use. I would simply remove the few bolts that secure the cable near the caliper and pop the cable off, then make sure the arm can move freely and return, if it’s sticking use some WD-40 as you work it back and forth to free it up then reinstall. I’ve corrected that issue half a dozen times on Accords and my own 13 Accord Sport

 

I checked the parking brake this afternoon. There is an equal amount of slack in the cables to each rear brake with the parking brake lever released. I disconnected the cable from the arm and it moves freely against the return spring, without any sign of sticking or binding. The spring moves the lever easily to the end of its travel. Most likely the piston is sticking a bit.