Has anyone dealt with a rear caliper piston that just turns but won't retract? The passenger side retracted fine but the drivers side just turns. I also tried turning it counterclockwise to see if it would move to make sure it wasn't seized and it extends out, but turning it clockwise like you're supposed to only retracts it to the point I started at; then it just turns and doesn't retract any further. Any ideas? It's a 2015 replacing the original brakes.

Thanks
Rob

 

The adjuster screw inside the caliper/piston stripped when you attempted to thread it back in. It’s usually due to bad brake fluid corroding the screw or a build up of corrosion on the outside of the piston but under the boot.

You can get rebuild kits for them but I recommend just getting a new or reman caliper because at least if it fails, the manufacturer is paying for a replacement. It’s also recommended to replace the hose with the caliper.

 

Thanks for the info. I suspected I'll have to replace it but thought I'd ask in case I was missing something.

 

So a final update: I gave it one last try before spending money and tried a better tool. I was always able to get the caliper to retract by using either those cheap cubes or a set of needle nose vise grips and never had a problem. This time it just took a better tool:

 

I can appreciate wanting to make it work but whatever kept the piston from retracting could also cause it to be dragging which will wear out new pads a lot faster. In my experience there’s rarely just one thing wrong with a caliper - usually if the piston is sticking, the guide pins are too, and in the case of your van, the parking brake cables as well.

Check that the brake isn’t dragging after a test drive by getting the wheel in the air and spinning it. It should turn somewhat freely - you should get at least one full free spin if the caliper is working properly. The pads only clear the rotor by a few thousandths of an inch so some drag is normal, but it shouldn’t take forcing the wheel to spin either.