Brakes- Help

Did you have the Brakes done at a Toyota dealer?
Because the Prius has 4 braking systems (Friction, "B" mode, Regeneration, and Parking, the hydraulics are quite complex and hard to Bleed. There is a maintenance mode to get all the solenoids open at once so it can bleed. While this CAN be done without the Toyota software, it is certainly not obvious.


I think this is the gen 3 system
Design and Simulation of Pressure Coordinated Control System for Hybrid Vehicle Regenerative Braking System | Journal of Dynamic Systems, Measurement, and Control | ASME DC

The Prius brakes often last about 250,000 miles before needing new pads.

 

Did they properly do the bedding in process while the brakes and rotors where replaced.?

 

Bleed the brakes and see if that’ll help. Also, when the rear pads are replaced, make sure the pads are aligned with the rear caliper piston nipple. You can ask @Mendel Leisk for a picture of it. All of the videos are on YouTube for those tutorials.

 

You know how to wake me up, lol.

Anyway: rear brake caliper piston should be oriented like this:



, when reassembling. In that orientation, there's a pin on the pad back that'll fall between the raised spokes on the piston face, and the piston will make even contact with the pad.

You want to ensure it stays that way: after the brake is completely reassembled (and assuming you've disconnected the 12 volt at the outset) pump the brake pedal multiple times, make sure to firm it up, get good contact, then reconnect the 12 volt.

Don't apply the parking brake yet. Go for a short test drive, and use parking brake only afterwards. The parking brake activation will attempt to rotate the piston, and the pin on pad back, between the piston spokes, will prevent this from happening.

For a final check, it's good to re-raise the rear, and check that the wheels spin easily, just slight drag at most, able to spin a revolution or two.

I'll attach the brake maintenance instruction.

 

Yeah I'm just concentrating on one possible issue: misassemble of the rear brakes, which is frustratingly easy to do. It's a poor design that requires mechanics or DIY'rs to do something very specific, not widely understood, namely the piston spoke pattern orientation. Do it wrong and the brakes will still go together fine, but will drag terrifically, and you'll eat rear brake pads, with a bevelled wear pattern, due to uneven pressure.

Again, just one possible factor. To check for this: raise the rear with parking brake released, spin the wheels. They should spin easily a turn or two.

@NutzAboutBolts has a youtube channel, and with google should be pretty easy to find, just google

nutzaboutbolts prius brakes

for example.

The Prius specific videos are also linked here, just go to:

Priuschat home page > third gen maintenance sub-forum

Pinned at top of that section is a thread with all the videos.