Replacing front brake pads

If you just ask at a dealership parts department they'll sort you out. Probably worth it to get the shim plates too. Be sure to disconnect the 12 volt battery negative cable before starting, and pressure the system by multiple tromps on brake pedal before hooking it up again.

 

You should have the brake system inspected and make sure the pads are all you need. There were some examples from colder climates where the rotors were completely rusted and needed replacement.

You can order genuine OEM parts online. Many dealers have online sales. I get my parts from the online shop at Camelback toyota in AZ

 

To what others have said, I would just add: if your pads are anywhere near needing replacement at 86,000 miles on a Prius, be sure that you also check for and fix whatever is wrong with your calipers, or you'll just be back there again.

While you're in there, be sure you check for a good flat smooth rotor surface on both sides, and make sure the caliper slide pins move lightly and easily. Check all the rubber dust boots (one around each slide pin, one big one around the piston) for any splits or tears. Fix anything that needs it.

When shoving the piston back in to make room for new pads, it is probably best to open the bleed screw and let the fluid escape there, instead of forcing it back up into the brake controls. That way, you are also changing out some of the oldest fluid in the system, which you'll get to replace with new when you top off the reservoir after you're done.

With the bleed screw open and a drain tube attached, you might be able to apply and release gentle pressure there to extend the piston slightly and make sure it retracts. (If you have let some escaping fluid flow out into the drain tube, then you can apply slight pressure so that only some of the fluid in the hose returns to the caliper, and you don't introduce any air that would have to be bled out). In good condition, these caliper pistons seem to retract about 0.3 mm when you let the pressure back off. That's the work of the rubber seal, and if it doesn't happen, you'll have dragging brakes until you rebuild the caliper with a new seal kit (which is reasonably priced at the dealer).

When you're done with the bleed screw, make sure there's a good, intact rubber cap on it (those also come in the seal kit). Without the cap, water (and salt, if used in your area) can get down to the base of the bleed screw and seize up the threads from the inside.

It's not a bad idea to just have a seal kit in your spare-parts drawer somewhere. It's inexpensive, and includes everything needed to rebuild both the left and right calipers. It works like an umbrella: as we all know, if you take your umbrella with you, that makes it not rain. If you have a seal kit on hand, your calipers will turn out to be ok and not need rebuilding. But if you don't, they will, and you won't want to wait for a kit to come in, and you'll end up buying a crummy replacment caliper at the local crazy eddie's.

Make sure you closely read the service manual instructions about when and how to top off the brake reservoir when you're all done. There is a brake accumulator that a bunch of fluid gets normally pumped into, and you won't be checking the right level unless you make sure that's returned to the reservoir first.

Regards,
-Chap

 

A good rule of thumb might be to replace just as much fluid as you drained. Theoretically you should never need more.

Also, be diligent about avoid air getting into the system: apply steady pressure on the piston, then crack the bleed screw, then close, only then stop pressure.

You want uniform bearing on the piston when pushing it in: it's plastic; someone here cracked theirs pushing it in.

 

No mention of turning or replacing the rotors, new pads, old rotors, now another set of used pads, new pads needed, repeat and rinse.
If you've never done a break job, honestly, why risk the possibility of no brakes. If you start replacing parts and then have to back up and replace the metal part, that's worn and, Needs turning, or replacing..you would have saved money letting Toyota do it, and it would be a factory job, not cheap, not deadly.

 

If I remember right, somebody did mention examining both rotor surfaces, inner and outer, for a good smooth surface. If that's not what you find, and it's gnarly, a local shop with a brake lathe can solve that for you. If it's just glazed and shiny, or only starting with the rust-in-from-the-edges syndrome and you've caught it early, 150 grit wetordry sandpaper, water, and a vigorous circular motion will be all you need. A brake pad makes a good block when sanding the rotor. If the pads have lots of life left and you're not replacing them, make sure they are also flat. If the rotors were started on the edge-rust thing, the pads will have chewed-away edges, which you can fix by turning the paper sand-up and repeating the circular motion for a minute or two, which you also want if the pad surface is shiny/glazed. (Wasteful, I know, you've probably just sanded off a year or so of your pads', what, 12 year expected life....) Don't breathe the dust, not supposed to be asbestos any more, but probably not the elixir of eternal life either.

While there is no such thing as "torquing your rotor" when you put it back on, there is such a thing as measuring the runout, and finding the rotor position that minimizes it. The manual explains how to do it. Requires a dial indicator, which used to be a pricy specialty tool, but you can get them crazy cheap now, and they have lots of uses around a car. If you skip this step, the car will not explode, but you may notice a bit of pedal pulsation or longer pedal travel, maybe even very slightly reduced brake and bearing longevity.

There are definitely service procedures I think about urging people away from, but when somebody comes along who seems to have grasped the basic idea of changing a brake pad, I can't really bring myself to try to scare them off. Brakes just fundamentally aren't that complicated. Even in the Prius (where, admittedly, what the brake ECU and actuator do is pretty fancy), what you're doing at the rotor/pad/caliper end is really not rocket science. It's one of the more accessible starting points for people who are interested in shouldering more of the responsibility of keeping their own vehicles roadworthy.

I encourage developing self-reliance in that area, because the little-known dark secret about Prius brakes is: the friction linings normally wear really slowly, true, but that can mislead people into neglecting the brakes, where a bunch of other problems may still develop over time. The problems aren't hard to fix if you catch them, and the best way to make sure they're caught is to say "ok, even though it's a Prius, I'm going to take the extra 10 or 20 minutes to check them, maybe every 2nd or 3rd tire rotation, and if everything moves freely, is wearing evenly and not glazed, put the tires back on and feel confident about my car."

Who is most likely to really do that? Whether you think the dealer or the corner service franchise actually did it when you paid them to depends partly on your trust quotient, and partly on which dealer or corner shop you happen to live near. It's most likely to really get done regularly if it's done by a clueful, self-reliant owner.

Now, everybody, some time or another in life, is at the stage of needing to become clueful first before jumping into something, and if the original poster here is at that stage, well, there are very good service manuals at techinfo.toyota.com and lots and lots of internet resources. (Some of those are bogus and unclueful. But not all of them.)

As far as the catastrophic mistakes you could make: well, you don't "torque" the rotors, but you do torque the caliper mounting bolts and that matters, so, own a torque wrench, look up the correct torques and use them ... make sure you understand the difference between foot-pounds and inch-pounds, so you don't have to learn how to extract a broken bleed screw. Check your work, count the leftover parts, make sure you stop correctly at the end of the driveway and the end of the street before you merge onto that 4-lane highway.

There are not really that many mistakes to be made that will leave you with suddenly no brakes. Most problems of that nature you're going to notice right away. Other mistakes may get you some very specific codes from the brake computer; a code reader is cheap, and when you look them up in the manual (which of course you've already downloaded) it won't take long to fix them. It is fairly easy to make mistakes that will give you draggy brakes and clobber your MPGs (and calipers and wheel bearings if ignored long enough), and lousy MPGs are embarrassing in a Prius, so of course if that happens, you fix it.

Cheers,
-Chap

p.s. on the off chance that anybody reads this, manages to find one of the ways to mess up that could cause abrupt failure, and finds a lawyer who thinks I caused it: go pound sand.

 

Not exactly sure what you're saying, oh evil overlord. But if it's that new pads require new rotors, I wouldn't agree.