Rear brake calipers

You need to push it hard as you turning with your channel lock. Also make sure the brake reservoir cap is removed while doing the brake job.

 

You don't really have to turn it at all. When I changed my pads, I first tried spinning it like you said, but it just kept turning without going in. Use a C-clamp to push it back in (might want to put the old pad between the piston and the c-clamp to distribute the force evenly)

 

I've only turned ours a little, to get the cross pattern in the correct orientation, like this:



So I can't say from first hand experience that screwing it in is the only way, but I'm very sure, from the Repair Manual and previous cars, rotating the piston clockwise is the only way to get it to retract into the caliper. You're basically screwing it in.

It'll go a lot faster with this disc brake piston tool (mount on a 3/8" ratchet wrench):

 

What year is your car? My '13 Prius v wagon doesn't have twist in rear calipers -- they just press in like conventional calipers.

 

Maybe a mini-drum brake setup for parking brake, on the v??

 

Yes, drum parking brake mechanism utilizes the interior of the disc as a drum.

 

Yeah, so it is:



For comparison, 2012 Prius (regular):



And just out of curiousity, 2016 Prius (regular):



(looks to have the same integrated parking brake mechanism as regular third gen)

 

Ah, so it's a V thing, not a model year thing. Thanks for posting.

 

I used a pair of needle nose pliers to turn the piston. So a good brake cleaning with brake cleaner is a good idea before you start. If it has been 100K+ it will be quite difficult to get the piston started but it will eventually start to move. Be careful to not cut the small rubber boot and you will need to compress it all the way if you have a new set of pads.

 

The cube shaped tool is cheap and readily available though. It's easier to use, safer too: no chance to slip, maybe nick the boot.

 

Bump to this thread: Few days ago, I helped a friend replace the rotors and pads on his 2016 Prius. At 40k miles (in upstate NY driving) the rotors looked pretty bad shape, so he ordered new F+R rotors & ceramic pads (Powerstop brand kit). We did the rear brakes, and the calipers were a bit cranky about being retracted, but we got the job done. He drove the car for a few days, noted that his gas mileage was not what it was, and we chalked that up to the pads breaking in. Then we did the fronts. A few days later, he asks me to come over and investigate really hot driver rear rotor. In 500 miles, about 1/3 of the ceramic rear pad was used up. Did a 1 mile test drive; front rotors cool, driver rear rotor very hot, passenger rear rotor slightly warm. Hmmm, says I, the calipers are not retracting properly. Using a Lisle brake piston retraction tool (it allows piston to rotate as it goes back), I worked the piston fully in on both sides. Very tough to move at first, then zip it moves quickly. Rebuilt the rear brakes, but after a test drive the rear rotors are still much warmer than the fronts.

So on my advice he takes it to a professional shop, and explains the symptoms, expecting to have to replace the calipers on both sides. The shop says nope, just exercise the pistons and turn them as they go in.

So, has anyone else had problems with Prius rear disk brake calipers sticking? The OEM set looked like the rear calipers actually had frozen, and were really doing nothing on the rear rotors; there was all kinds of crud on the inner face of the original rotors when we took them off. My first use of the Lisle tool took a bit of strength to free up the rear caliper piston on the first go-round, and usually that travel is enough to clean up the piston.

The front rotors and pads upon inspection run cool, and look fine, barely worn.

My worry is that this is a problem where the rear pistons stick in use, and that he will end up ruining not only his new pads but his new rear rotors.

So, has anyone else seen this problem? If so, how did you solve it? Thanks in advance...

 

I feel like I'm being paged, lol.

Short version: there is a stubby pin on the rear brake backing plates (hopefully your aftermarket pads have the pin, should have). On the caliper there is a 4 spoke raised pattern.

It's imperative that when assembled the spoke pattern be oriented like an "X", so the pin is between the spokes.

Also, when everything is back together, you want to pump the brake pedal multiple times, make sure everything is well seated.

Then reconnect 12 volt neg cable (should disconnect before any disassemble) and take the car for a short test drive, taking it easy on the brakes.

Then raise the rear and verify wheels spin semi freely, say 2-3 rotations with a push.

Where you are now you may have rust build up on about 50 % of inside face of rotor due to pin riding up on spoke, not contacting properly. May need to remove and clean up.

Just thumbing on a phone right now, maybe post more info later.

 

Hello, I am new on this forum, so I hope I'm not .
I have a couple of questions regarding a 2010 Prius : 1- caliper replacement and 2- non functioning electric buttons on the steering wheel. à
1- I am about to replace the rear left caliper and would like to know the issues related to this operation. Should I disconnect the 12 V battery imperatively? Can this replacement produce some DTC on the OBD record so the car would not start or be operational afterward ?

2- On the steering there are two circular touch pads including 5 buttons each. My problem is that two of the 5 buttons on the right hand side touch pad of the steering wheel are not functioning anymore (so for example, I cannot change the ''mode'' on the display panel). Is there any issue in trying to remove the touch pad to check the contacts ? Anyone has ever encountered this problem?

Many thanks for advices on issue #1 and/or #2.

 

@Mendel Leisk will be along shortly

 

Just the one; is there some back-story?

 

Hello Mendel,
yes just the rear left one. For history, the car has 377000 km and we drive it in Montreal rusty conditions. The rear right caliper & bracket were replaced in 2020 at the dealership. This was done altogether with installation of new pads on both sides L & R (Found the bill quite ''bitter'' though!!!). So this fall, I decided to do the brake maintenance by myself. Changed the slider pins on both sides L&R and found out that the left bracket was leaking. The housing of the bottom slider pin had a pin hole on its side, so the pin was jammed and grease had leaked onto the bracket casting. Also noticed the inner pad had more wear than the outer one. I ordered replacement bracket and it came as a complete kit including bracket and caliper. I changed the bracket already and seems to still make some squeeking at low speed. I wonder if it could be the caliper not working correctly and if I would be better off changing the caliper as well. Changing the bracket did not involve anything else than unscrewing and screwing 4 bolts and pushing the caliper cylinder a little bit, so it was easy to do for a newbee. However, changing the caliper would involve playing with an open brake fluid circuit. And there might be some issues with the braking system that I am not aware of. Would appreciate your good advice.

 

The Prius brakes, and rear brakes in particular, have some "foibles". I've done straightforward disassemble/clean/lube of ours, just taking the pads/shims out, and relubing the caliper slide pins. I've not replaced calipers though, and I'm not familiar with the ramifications of disconnecting the caliper brake lines, introducing air.

I'd suspect if you didn't leave the brake lines disconnected any longer than necessary, and kept the open ends plugged as much as practical, you might be able to follow up with the non-Techstream brake bleed method. It may though prove necessary to use Techstream brake bleed method. It'd be worth a try to do the non-Techstream method, and if it's not effective (you still have air in the system, and/or codes), either acquire a laptop, Techstream and cable, or take it to dealership for a Techstream method brake bleed. I'm out of my depth here; maybe @ChapmanF will chime in.

With the rear brakes if you're having uneven pad wear, it could be the piston orientation thing, as described in my post #13. In particular, you want to disconnect the 12 volt at the outset, and leave it disconnected for the whole procedure. And pump the brake pedal multiple times before reconnecting. This accomplishes a couple of things: prevents the brakes "pressurizing" while the caliper's off the rotor (which could pop out a piston), and avoids the system detecting excessive brake pedal travel and throwing a code.

I'll attach some repair manual info:

 

Just in the interest of keeping the nomenclature straight, there is no such thing for Gen 3 as a "non-Techstream brake bleed method". There is not anything in the manual that is called that. Mendel attached manual sections about a non-Techstream fluid replacement mehtod, where fluid replacement is what you are doing if you already have a properly-bled system with old fluid and no air, and you're going to replace that with new fluid without allowing in any air.

That said, I would pretty much buy Mendel's reasoning that if you are doing the rears, and only a small amount of air entered at the rears, you probably can get away with (ab)using the non-Techstream fluid replacement method to bleed them.

But bandying about the phrase "non-Techstream brake bleed method" is just a mistake.