Uneven Pad Wear on Rear Brakes

[Egan]

I've seen some threads on here with hints of answers to my question, but nothing concrete. I replaced the pads on all four corners on my wife's LGT at about 47K. At 55K I noticed the left rear rotor looked badly grooved. I pulled the calipers to find the left rears were essentially gone (no pad wear indicator on this side of the car - thanks Subaru! ). The right side still looked brand new.

 

I had the rotors turned (just barely came in to tolerance) and put in new pads. I've been watching them closely over the last 2 months and at 57K the lefts are about 50% while the rights are perfect. When I put in the new pads 2 months ago, I inspected the calipers for any signs of piston problems and didn't see anything. I also re-greased the guide and lock pins.

 

Obviously, something is causing the pads to not disengage and they're wearing. What else should I look at? Bleed the brakes?

[tbssubaru]

parking brake out of adjustment maybe? only thing I can think of that would cause something like that

[cchen1]

tbssubaru - The LGT parking brake works like a drum brake (against the inner hat portion of the rotor), and has no effect on the caliper, so that wouldn't cause this problem.

 

Egan - since the sliding pins and stuff seem to be working, it would seem that there is something wrong with either the piston being frozen after it is engaged (though you said you didn't see anything wrong) or pressure is not being released after you let off the brake pedal, so pinched brake line on that side.

One test for a pinched line could be to step on the brake pedal hard once, then go and crack the brake bleeder of the suspect caliper. If brake fluid squirts out, you most likely have a bad brake line.

[Egan]

I'll check that this weekend. Thanks.