On changing the brake pads in my 2010.

Thanks for the good write up. The YouTuber's have something on their side called edit that makes them look fast and good.

 

Good write up. I never disconnected the battery. I just rolled down the windows and left my fob in the house. All worked well when I was done. Did all four at the same time. Could have gone another 100K on the brakes. LOL. I love my Prius!

 

Toyota USA, inline with most manufacturers, recommends a full brake service, regardless of pad thikness, every 3 year or 30K miles, whichever comes first. Too many owners seem to conflate brake job with pad replacement. Better late than never though, thanks for the write up.

Toyota makes a specific grease for the pins and boots. I've been using Sil-Glyde Brake Lubricant for years, on various cars, no problems. For contact between pad backs, and shims, and calipers, Permatex Anti-Seize is what I've been using. Apply it to the part that's going to lay atop the other, just a thin layer. That way you get it just where needed. I would leave the pad ears (the two nubs at the end) clean, they're too exposed, and grease would attract grit.

I would play it safe, disconnect the 12 volt. It only takes one lapse, opening the driver's door while caliper is off.

And just before reconnecting, tromp the brake pedal multiple times. Don't be too quick to apply the parking brake either. Start it up, take a short test drive, and upon your return apply/release the parking brake several times. Then raise the rear (chock front wheels) and check that both wheels are spinning fairly freely, above to spin 2~3 revolutions with a good push.

If they're sticking, it's likely the rear caliper has managed to rotate, needs to repositioned and reseated.

 

It's good to mention that Toyota specifies a specific type of grease there. It would be even better (especially given the OP's emphasis on silicone) to briefly mention just two more things about the specified grease:

• It has an actual name and part number that are not shrouded in secrecy, and
• it is not a silicone.

If you buy the Toyota rubber parts kit, there's a little packet of the right grease included.

Testimonials about other products, Sil-glyde or whatever (which is a silicone) are all very well, as long as readers are clearly informed what the specified grease is, and that the alternative stuff ain't that. It's only fair to be up front about it.

Agreed here. Toyota recommends nothing on those parts. When you buy those hardware bits (the "fitting kit", as it's called), they come with a dry, Teflon-like coating that is very slippery without attracting grit. It eventually deteriorates.

 

'Scuse my ignorance, but that's the part I do not understand. Why would the system try to send pressure to the caliper, as long as the brake pedal is not touched? The pump runs when you open the door only to maintain pressure in the accumulator, not to apply brakes, in my understanding.

 

The pump did not run when I opened the door. I think it only runs when the fob is in proximity and open the door. I keep my fob in the house when I work on the car.

 

Two different things get mixed up sometimes.

When you open the driver door after the car has been off for a while, that will trigger the pump to run. Just as you say, that only pumps up pressure in the accumulator, and does not send any pressure to the wheel cylinders.

Now try something else: after parking the car and shutting it off, just sit there quietly in the driver's seat for a few minutes. A few minutes after the car was shut off, you will hear some clicking and squirting noises from the driver's side of the firewall (you may also hear the pump run again, depending on the pressure). That is a self-test of the braking system, and that does send pressure down the brake lines (the valve clicks and fluid-squirting noises you hear). That would be a bad time to have a caliper apart (or, worse, your fingers in it).

As far as I know, that's the only time that self-test happens: just once, a few minutes after the car has been parked and turned off, every time. I'm pretty sure, if you wait for that before starting work, it won't sneak up and surprise you again. And just opening the door and triggering the pump-up will not give you a problem.

But sometimes what's written in the forum isn't careful to distinguish those two different things.

 

Thanks for the write up ChapmanF. I have found that if the FOB is not present, the pump does not activate when the door is opened, or even pressing the brake pedal. I replaced all four brakes and purged/replaced the fluid and the pump never came on. YMMV

 

Yep! I've wondered about those strange post-shutdown thumps ever since my first test ride in a Prius. So I can lube my slide pins without disconnecting the battery or worrying the piston will suddenly be ejected from the caliper?

Thanks!

 

I think I'll continue to disconnect the battery, just in case.

 

Welp, what I'll say is I think that self-test only happens the once per drive cycle, a few minutes after shutdown. I've never noticed it happen any other time. So I think you probably won't have trouble if you've waited for that to happen before diving in.

I don't think anything in the manuals promises that (or goes into much detail about it at all, really), so in your own approach you'll probably be figuring in your own level of comfort with risk, and how comfortable you are relying on what I think.

You can avoid the risk by unhooking the battery.

 

Tested that this morning. fob not on me, well away from the car: opened the driver's door, the pump still runs.

 

Thanks Mendel! I did not experience the pump coming on opening and closing the door when I changed my brakes. And we pumped and flushed the old fluid out with new fluid and the pump never came on until I pressed the start button. Maybe because I had already driven the vehicle and the pressure was still up. Strange creature these Prius. YMMV

 

Yeah it's not difficult to test for yourself. Definitely do this before pulling off a caliper.

I like the car to be comatose, till the brakes are completely back together, and the brake pedal's been pumped multiple times, to take out any excess travel.

Maybe overkill, don't care, lol.

 

Mendel, I had the same thing happen to me while I was replacing the control arms and front wheel bearings. I opened the door without the FOB to get some paperwork and the pump came on. It pushed out the caliper pistons. I didn't realize it until I went to put the calipers back on. The loaded caliper wouldn't fit back on the rotor. I had to collapse the caliper and it all went back together. Could have been worse.

 

As covered a few posts up, simply pumping up the accumulator won't have been what pushed any pistons out. The accumulator is not the pistons.

If the system later conducted a self test, that could be what did it.

 

Whatever does it, disconnecting the neg battery cable stops it.

 

How was this done?