Front and Rear Brake Pad and Disk Replacement

A simple cleaning with a water hose will get the discs to rust, and that's perfectly normal.
Maybe it has rained recently and you haven't driven a lot since...

 

Hey! I resemble that remark! Us ruffian oiks have feelings too ...

Just standing on the sidewalk, I've felt my bladder control weaken as one of them slowly drove by "whooomp boooooooomp whooooooomp booooooommp oh hell, where's the lavy?"

That sort of music is probably handy for doing seismic surveys

 

Oh, sorry. So it wasn't a typo! Ok, I get your point now. Didn't realize that "manly" was short for "gentlemanly".

Thanks for the clarification!

 

The rust is just on the surface, don't let them con you out of your money.
I had an Opel Astra before my Prius, it had the exactly the same rust on the discs, after parking for 2 or 3 hours.

 

Everything BUT the North American models got rear discs in all models, Why not us, hhmmm? Why do they give us the cheap crap instead of the good disc brakes?

 

Because Toyota don't think you would pay what the rest of the world pay for Prius. See my earlier post.

 

My 2004 rusty front discs/rotors are down to 20.2mm. I've been searching for a thread here with photos how to change. I need new pads too
Any links??

 

Actually, rear drum brakes can work very well. I actually prefer them on the Prius. I don't know about today's technology, but years ago drum brakes had superior stopping power to discs. The only real advantage to the discs was that they cooled down quicker. So if you were racing, or if you had long drives down mountains, there would be less chance of the brakes overheating.

I really like the fact that drums don't spray "brake dust" all over your wheels. Much easier to keep the wheels looking nice, less work when cleaning or detailing. Since on the Prius, most braking is regenerative and comes through the front wheels only, even on hilly roads the rear drum brakes should hold up just fine. And I like the look of them on the Prius, also. They have a nice, black finish on them. You could even remove them and paint them red or blue or whatever if you wanted. I imagine that could look really nice.

Another problem with discs: many manufacturers today are making the rotors thinner than they should be. They tend to warp more easily as a result. And often they cannot be "turned" to resurface them. So even though disc brakes can potentially cool much faster than drums, they can also be damaged much easier than in years past.

It's very common to go in for a brake job and hear that the rotors need to be changed, either because they are pitted, grooved, or because they have warped. When you ask, "so just turn the rotors (the process of shaving some surface off the rotors), you find that many times they can't be turned, because they are already so thin when new, that turning them would bring them below allowable specifications!

Warping occurs more frequently nowadays with disc brakes from what I've heard (and experienced). And it can happen quite suddenly. Again, this is because the rotors are being made too thin, due to the manufacturers trying to save save weight and cost.

It can happen like this: you'll be driving with a lot of people or a heavier load in the vehicle. You have to make a sudden, hard stop, and soon afterwards you shut off the car. The next time you drive it, after it has cooled down, you feel the brakes "pulsing" when applied. You bring it in to the shop and find out that the discs have warped. The excess heat generated by the sudden stop or stops could not bleed off from air cooling quickly enough since you stopped driving soon after the brakes got overheated. The brake pads retained too much heat, and after the car stopped, caused the portion of the rotor that they are sitting on to expand, which caused the rotor to warp.

This is what happened to my Chevy minivan when it had relatively low mileage. I found out from the shop that I've used for years that this is very common with modern disc brakes.

(Addendum: I since found out from a relative who owns a repair shop that the after some heavy braking with disc brakes, you should drive around the block for a few minutes without touching the brakes too much. This will allow the brake pads to cool down so that they don't warp the rotors.)

 

Keep in mind that if you need to bleed the front calipers, you will need the dealership scantool to command the system to open solenoid valves and run the boost pump

 

I dont believe I'll need to bleed the brakes to insert new pads.
It would be good to see some photos

 

This is the caliper assembly



You *must* wait at least 2 mins after powering down the car, before attempting to remove the two bolts and caliper slide pin assemblies. If you fail to do so, the brake boost pump may run and the pistons will be forced out the caliper

The slide pin will probably rotate when you attempt to remove the bolt. A skinny wrench - IIRC 10 mm - can be put on the machined edge of the slide pin to keep it stationary

 

Oh,just a heads up, when you squash the caliper cylinder to get the old pads out and new pads in, a diagnostic code C1341-C1344 may be stored

 

so why are the discs so expensive?
I thought they must contain the wheel bearing

It looks like the process is
wait ten minutes
press caliper cylinder in
remove pads
remove 2 bolts holding caliper
Is the disc held on with anything?
maybe insert two bolts into disc holes to push off disc
fit new disc
refit caliper
press in caliper cylinder - watch fluid doesnt overflow master cylinder reservoir
fit new pads

 

I dunnu. They're paper thin, I wonder if you could grind them once?

No, that is in the hub assembly.

Sounds right. You may set the brake diagnostic codes I mentioned

After you get the caliper bracket off



you must remove the axle shaft nut before the disk can be removed, to get to the hub bearing if need be



I guess I should mention that you're taking on this job with no guarantee on my part. I'm providing the information "as is" with no specific guarantee of merchantability, fitness to task, etc

The problem with the Prius braking system is the various sensors involved



Get any of it wrong, you could lose all braking. There are various failure modes



Only the dealership scantool can command the system to properly bleed the brakes

 

Unless they're actually rusted through (which would be even more surprising unless they get dipped in salt spray frequently) this sounds like surface rust and nothing at all to worry about. Try braking hard a few times and see whether it disappears.

 

My Prius has only done 27k and needs all discs and pads need replacing. My first prius needed new disc and pad twice due to corrosion. Guess the cars dont like the cold damp british weather. This will be the last one I own there just to expensive to run.

 

This has to be a troll....

 

No, just dealers completely unnecessarily upselling brake services. Owners largely do put their trust in the mechanic giving them accurate information, rather than verifying for themselves - you do need a lot of tools, stands and space to safely remove the wheels, check the disc and pad dimensions, and assess corrosion or pad glazing.

Apparently we do have slightly different brake system specs, the front discs are 25mm wide rather than 22mm when new (Gen 2). The pads may be thinner, when new, than the US spec of 11mm. We have rear discs on the Gen 2, where the US has drums.

The corrosion - which is slight - can be eliminated by shifting to neutral (which inhibits regen braking). It can be prevented by doing this - or braking hard - after travelling on wet roads and particularly if road salt has been used.

 

Anybody able to tell me the tightening torques for the front caliper bolts, the slide pins, and especially the axle nut?