Back Yard Brake Pad Replacement for 2015 Gen III Prius

Before starting, disconnect the 12 volt battery negative cable. Leave it off till everything is completely reassembled. The car can "pressurize" the hydraulic system, when off, in particular if you open the driver's door. You don't want that to happen when the brakes are open.

Also, before reconnecting the 12 volt: tromp the brake pedal multiple times, pressure up the pedal. Not doing that, the car might detect excess brake pedal travel, throw a code.

With the rear brakes, you must get the caliper piston orientation correct. There's an X pattern on the face of the piston, and it should be oriented thus, like an X, so that a stubby pin on back of brake pad sits between the spokes of the pattern.

Then you want to make sure it's well seated thus (previously mentioned multiple presses of brake pedal when done). Don't use the parking brake directly after either: test drive the car first, being gentle on the brakes. After that, apply/release the parking brake several times, raise the rear, and verify the wheels spin semi-freely. The should be able to free-spin a couple of revolutions with a good push.

I would recommend the Toyota brake pads.

I use Sil-Glyde Brake Lubricant for the caliper pins (and a bit on the boots), and Permatex Anti-Seize on the pad backs and shims, and points of contact with the caliper.

Repair Manual info in attached:

 

That's a good approach.

Oh: when pushing in the front pistons: they're some high-tech plastic, so be sure to use full/uniform bearing on them. If using something like a C-clamp, put the old pad, a plate or some plywood, something big enough to cover the entire piston rim.

 

do the pads even need replacing?

 

Don't bother us with tirival details.

One thing, Toyota does say to go through a full brake inspection, tri-yearly or 30K miles, regardless of remaining pad depth. That's a good interval, which most owners (and dealerships?) seem to ignore??

 

With the wheel on you can more-or-less see the pad thickness. With the wheel off much better: the outside pad directly, and the inside pad by looking through the opening on the caliper "shoulder", you get an edge-on view of both of them.

Then you know in advance if you need to get in pads. But yeah, tri-yearly or 30K miles is a good interval, regardless of their thickness.

 

Flipping the caliper up (one slide pin unbolted, other one loosened) lets you easily slip both pads out and get a full view of their condition, and the condition of both sides of the rotor. (The inboard rotor surfaces have an odd knack for rusting in a concentric-rings pattern.) In pretty much the same motion you can wiggle both slide pins in and out some and decide whether they feel still greasy or dried out, and spot any damage to the rubber boots.

Mine pretty much always feel still greasy after a couple in-n-outs to get 'em moving again, and I do nothing more to them.

If the springy clips that the pad ears slide in still have their factory dry teflon-like coating and the pads easily slide, you just put the pieces back together, pivot the caliper back down, secure the pin bolts, and you've done your brake inspection. And if you measured the pad thickness while they were out, and plot your last few measurements against miles driven, you'll have a pretty good idea when you'll hit the 1 mm minimum.

It might not be for a while.

The regular inspections are really what keep everything in good order, so you don't end up with parts worn out prematurely.

 

For years with Honda that's all I ever did. Well actually just removed the bottom bolt, didn't loosen the top bolt. The Honda Shop Manual instruction pictures showed pad inspection/replacement thus: just swing it up. Then I started twigging to removing both top and bottom bolt, relubing the pins. Maybe overkill, I don't know. One thing, even though I didn't loosen the top bolt, it seemed to rotate up just fine: it's hinging on the caliper pin, which is free to rotate?

 

I believe you need a certain tool to work the rear pistons back into the calipers if you're replacing the pads.

From page 33 of that attached pdf:

The manual covers piston removal, which should not be necessary, but notes using the mysterious SST to work them back clockwise. They have that X pattern on them, so you can file a mating surface into an old 1 inch socket if you want. I believe you have to turn, but I'm NOT sure. You definitely have to push, though, and not just turn.

 

Google "Lisle 28600". It's a small cube-shaped attachment for your socket wrench extension. And yes, you push and turn that wrench by hand.

 

If you have an AutoZone in your area, part number 27111 is a comprehensive loan-a-tool that will do just about all vehicles. And if when rented, you like it, it’s yours to keep.

 

Also called a dice.

It comes in handy from time to time.

 

You only need the tool after actually having to change the pads.

Most inspections will go: flip ... "yup, still just fine" ... unflip ... done.

 

Harbor Fright has their version, too. Item 68972.

 

Just google brake tool, it should show up. Add "cube" narrows it down.

You can rotate it just with needle nose pliers tips, but it's awkward and difficult, especially to screw it all the way in.