About 2 years ago I had new brakes put on the prius. October 2016, the left rear caliper froze. New calipers, rotor, whole bit. June 2017, left rear caliper failed...took it to the same shop. They said I must have hit something to damage it...installed new calipers, rotors, etc. Now today in Oct. 2017 my prius failed the state inspection. Left rear caliper frozen and leaking. I will be taking it back to the shop that did the work to have them look at it, but I'm not inclined to have them work on it again. What would cause this to keep happening and what should I expect the shop to do about it?
You need to be very careful with rear caliper piston orientation (X orientation, not "cross") when reassembling/mounting, and ensure that orientation is maintained, by seating the piston solidly against the pad backs (repeatedly pushing brake pedal, then a test drive), before applying parking brake. Failing to do this, the piston may rotate, the spoke pattern on its face rides up on the pin on back of inner pad, results in off-kilter brake application, lots of drag, scored/rusty rotors, all sorts of fun. Does your shop have access to Toyota Repair Manual info on brakes? The rear brake piston orientation is explained there. I can post it in a bit.
During troubleshooting, the shop can determine if it's the hose or caliper by opening the bleeder screw. If it stays froze after the bleeder is opened, the problem is the caliper or slide pins. If it releases after the bleeder is opened, the problem is hydraulic, usually the hose collapsed.
If it's the hose now, was it also likely the hose 4 months ago? This would be my 3rd set of calipers and rotors from the same shop in 1 year.
Here's the Repair Manual info. Look for this pic: it's the caliper piston orientation that must be used and maintained, when the brakes are put back together. If the back end is raised and the brakes are seriously dragging when spun, it could be due to this mis-orientation. A couple more clues that would point to mis-orientation of the piston: 1. A large area of the inside face of the rotor rusty. 2. The pin on back of inner pad looking bevelled, chewed up. This is how that pin looks new:
I just did a rear brake maintenance on ours, which I do tri-yearly, regardless of miles, pad thickness. My strategy to avoid this issue: 1. Disconnect neg lead 12 volt at beginning. 2. Orient piston pattern as mentioned and reassemble brake. 3. Tromp brake pedal till firm. Do not apply parking brake. Test spin wheels to verify minimum drag. 4. Reconnect neg lead. Test drive, braking gently. 5. Raise rear end and ensure wheels continue to have minimum drag. 6. Lower car, and then and only then, apply parking brake, gently the first time. 7. Repeat step 5 a week or two later.
So, they redid the whole left rear brake set up for free, but here it is 6 weeks later and the same $&@_ brake is grinding again.
Apologies, I never did update this. Apparently the shop was using aftermarket parts that were slightly off size. They fixed the problem, made up for previous costs and I haven't had the problem since.
Doing my brakes over the years, it never even occurred to me that there were aftermarket brake parts. These were import Hondas exclusively, and maybe there were less aftermarket options then, not sure. But yeah, sticking with OEM, you have no fit problems: that's what the dealership service departments use, and if there were any problems they would be fixed quickly.
Reminds me of the purty-lookin' aftermarket reman caliper I bought once because I was in a hurry and didn't have the rubber kit on hand to rebuild mine ... the one that turned out to have zero mm of piston return, right out of the box....
