Rear Calipers Frozen

If it was certified, you had some sort of warranty period. How long and how many miles after you bought the car did you experience the problem? If really soon, the dealer might need to step up and reimburse you for the repairs.

 

Hmm, I had that "super rare" problem, after working on the brakes myself. The rear disc brakes have integrated parking brake mechanism, and it's very easy to put them back together wrong, and thereafter they drag royally, apply uneven pressure. There's a pin on the inner pad backing plate that MUST be well seated and locked in between the raised spoke pattern on the caliper piston face.

 

My 2010 had a frozen rear caliper (driver side).
I replaced it myself for $50

 

welcome! 2010's seem to be the most common, they must have reworked them.

 

I think I had that issue on my 2010 with 50,000 miles. My right rear outer pad wore very unevenly and eventually the backing plate wore into the disc before I noticed. When I replaced the right rear pads, I also did the left rear. It had the same issue, but it's outer pad, while wearing uneven, was not quite to the backing plate. While there I also re-greased the slides.

Being relatively new to the Prius, is that the symptoms of a frozen caliper?

I sure hope my maintenance will take care of it.

Comments?

 

You are mixing two different issues. Normally, the original pads should last a long distance, driver braking style permitting, when the calipers are properly free-floating. But frozen calipers bollix any pad life expectations.

I've experienced frozen calipers on two traditional non-hybrid cars. One was from corrosion from age (greater than any Prius has yet reached), the other from my region's new-found love of winter salt.

 

I don't think this is so rare based on posts I have read on this forum.

Seems that lack of lubricating the pad retaining pins is the issue.

I also agree (what does certified mean?) could be a covered/ warranty item.

Good luck.

 

So you would not suggest replacing the left rear brake caliper by myself?
I have never done anything like this before, although I did watch the process of a non-professional I hired replacing the brake pads for me and it did not seem to be over-complicated.

 

At this juncture, maybe first just check the condition of the rear brakes: raise the rear of the car and try spinning the wheels, verify they're spinning near-free. Being disc brakes, there will be minor drag, but with a good push they should easily continue to rotate an additional turn or two.

By "replacing" you mean reinstalling, the caliper? A DIY'r can do this. The main issue is to ensure that the pattern on the caliper piston is oriented thus:



This will ensure that the raised spokes (shaded) fall on either side of a stubby pin on the back of the inner brake pad. Assemble everything thus, pump the brake pedal multiple times to ensure good contact, and reconnect the 12 volt battery negative cable. Give the wheels a spin to verify they're near-free spinning, lower the car, do not apply the parking brake. Take the car for a short test drive, apply the brakes gently (always good practice after a brake job), and on your return apply and release the parking brakes a few times. Then raise the rear of the car once more, and check that the rear wheels continue to be near-free spinning.

The issue, is that if the piston's pattern is rotate other than shown above, or the piston manages to rotate when the parking brake is applied, the raised spokes will be bearing only on the pin on the brake pad back, causing very uneven pressure, and constant drag.

 

Try resetting the rear caliper with this tool to see if it is seized, can't trust to many mechanics these days.
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