Brakes, Rotors & Pads

Brake jobs are based on need not miles. Do you hear or feel anything abnormal? If not tell them no. Also rotors are rare to replace. Pads will squeal


iPhone ?

 

not one in a thousand will need new pads and not one in Ten thousand will need rotors at 100,000 miles.

Your roters might need replacing if the car is parked next to salt water and never driven over 30 MPH.

Have them send you pictures and share them with us.

I lost ALL trust with dealer "service writers" when one called me back saying I needed a new interior air filter when I had just replaced it the previous night.

 

Our front pads are down around 6 mm, at 60,000 km. By 100,000 miles I hazard I'll be one of those "one in a thousand".

Also, there is more to brake inspections than just pad replacement; regular disassemble, inspect and relube is warranted, and specd by Toyo.

Rotors, I might push back. If they're well above min thickness, looking good and you're not noticing any pulsing.

 

If you can take a wheel off you can see how much pad life there is. They start around 10 mm, and once they're down to 2 mm the party's pretty much over. Minimum is 1 mm, but even if they're 2~3 I'd be getting nervous.

The outer pad thickness can be seen relatively easily; the inner you can check by looking through the opening in the caliper shoulder.

Lug nut torque is 76 lb/ft.

(I've already replace the rears on ours. I screwed up on an intitial inspection, reassembled with the piston misaligned. So I just threw in the towel and replaced them, only around $100 for pads and shims. The rotors looked terrible at the time, but appear to have "healed" themselves, look fine now, no problems.)

 

Routine flush, clean and lube is considered normal maintenance for all brakes...even Prius. However, the need to replace pads and rotors depends on a different set of variables. Rotors have the minimum thickness stamped/cast on them and are checked with a micrometer...pads are measured as stated above. Excess pad and rotor wear can and will occur when the slide pins are not lubed or the caliper piston sticks. If left unaddressed to long then the wear indicator rivets on the pads will eat/groove a rotor in nothing flat.

Have them show you in person...not just some numbers on a piece of paper.

 

'they have been very good' as in, they have recommended a lot of unnecessary services along the way, and your car is running fine?

 

I've been servicing my Prius this whole time, it has 103k miles and I haven't had any issues with it. I rather do the labor myself than to pay for labor and parts. I haven't done anything major either, just the regular maintenance here and there. If I were you, I wouldn't just take it from someone's recommendation, because that's their bread and butter. I would pull the wheel off and inspect the brake pads and rotors to see if it requires replacement or not. You can replace the brake pads and rotors yourself too. You'll be saving a lot of $$$ in the long run. The only thing I would bring my Prius to the dealership is for recalls and TSB since that's free.

 

Key word...servicing. Thanks for the videos buy the way.

 

no problem, glad we could help and thanks for watching, because that will help us in the long run

 

Anyone have an issue with rear brakes needing replacement at 50k? My fronts look great, almost new, but the right rear is hitting the rotor. Really odd since I am very gentle on my car. I need to take off the rear wheels and see what's up back there. Guessing a bad pad. I have replaced breaks for over 30 years. But this is my first attempt on a Prius. Anything different on this car that I should know about.

 

See my last paragraph in post #6. And, they were fine till I opened them up, messed things up. Reassembly is a bit tricky: there's a pin on the back of the inside pad that must be positioned between the spokes on the caliper piston face. If the pin rides up onto a spoke it skews the whole pad, drags badly, puts uneven pressure on the disks, pads.

Basically, you need to assemble everything correctly positioned, and then do multiple pedal pushes make sure everything is well seated. For insurance, drive the car a day or two, then raise the back end and make sure the wheels are relatively free spinning.

 

NutzAboutBolts has a video for this.
Nutz About Bolts Prius Maintenance Videos | PriusChat

What's most different is don't open or close the car door when you work on the brakes.

 

Disconnecting the 12 battery negative cable is effective too, just in case there's any other "gotchas". It unfortunately toasted your memories: radiio presets, trip meter, maybe windows auto functions. But it is safe.

 

Tks for the advise and the hints and the videos. Yea not sure what happened to my right rear but it was making noise on and off for a year or so. Since I know the Prius brakes last soooo long I just assumed it was crap between the pad and rotor occasionally. But after a look I see the outer portion of the rotor is chewed up a bit. So the first step,will be to remove the wheel and caliper to inspect the pad. Maybe one fell out???

Not sure what to expect but the videos and advise sure help. Hate to try to save money and secret it up worse...lol

Just odd that that one side is having an issue and not the other side. Maybe it had a problem right from the start and I did not notice. It's brakes were operating fine and like I said I don't hot rod a Prius.

If I have to replace the pads, can I assume I just open the master cylinder and then get a tool to push the piston back slowly? Or is there a trick to the too.

Many Tks again...

 

To retract the rear pistons you have to screw them in. Utilize the cross-pattern on the piston face to accomplish this. It can be accomplished with a pair of needle nose plier tips pressed against the pattern, but it's much easier with one of these on a ratchet:



I would put money on the problem being due to the inner pad's backing plate pin riding up on the cross pattern, due to sloppy seating. If you get an opportunity to see the inner face of the rotor, you'd see it's surface partially rusty, due to skewed pad, lack of contact. Also, the pin will look bevelled, chewed up.

The quickest way to see if anything's happening is to raise the rear with parking brake off, see how easy the wheels turn. If you don't have a floor jack: put wheel chocks on a diagonally opposite front wheel, release the parking brake, raise one rear corner with the scissor jack. Start with the side you're suspicious of, then the other side if you're inclined.

Normally there will be a slight amount of drag, no more.

Here's how a problematic inner pad looked in my case, where the pin was riding up on a piston spoke:



And the inner face of rotor:



New pad set, with the inner pad pins circled:



Relube the caliper pins with something like SilGlyde, and apply a sparing amount of molybdenum anti-seize on all faying surfaces of the pads, shims and caliper contact points.

When I did this the rotors were in bad shape, and pretty scored. After assembly they sound really bad, due to the new pads contacting the inner face rusty zone. A month later: no noise, and rotors looked like new.

 

You must've meant " ...new PADS contacting ... "?

Otherwise, your usual good write-up on that topic.

 

Wow Tks for the great explaination. But I do have one question. What do you mean by moving the piston in by screwing it? All the other cars I have worked on I forced the piston back using a simple devise and opening the master cylinder. Are you saying I don't have to do this on the Prius?

I never saw a tool like the one you show? I have a lot to learn. Since I have never worked on this car's brakes before I have to assume they were messed up from the factory. But unfortunately it's too late to bring it in under warranty.

 

the rear piston is a screwed on type, so you insert the cube into the caliper piston indent. You can see on the cube itself, it has 2 nipples sticking out, you will insert that on the caliper piston and then you use a 3/8 ratchet and stick it in the middle of the cube and you just turn it clockwise and the caliper piston will go in. It's not a pressed in type piston basically.