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New Brakes Squeak, Mechanic Doesn't Know Why

We have a 2005 Toyota Corolla whose brakes have been a problem since we bought the car four years ago. Every time our mechanic changes the brakes they squeak. They do not squeak for the entire time you hold the brakes, nor do they squeak when you slam the brakes. They squeak once when you step on the brakes to come to a slow stop. This go around with the brake replacement, our mechanic has put two sets of new pads and shoes on. The first were the ceramic kind, this next one is the Toyota brand, the highest quality. He has no idea why the brakes are still squeaking.

First question, is this dangerous? The second question is, what the heck is going on? We have been back to him so many times. Any and all thoughts are most welcome.

It probably isn’t dangerous but it could be the brand of pads he uses. Some definitely squeak more than others.
These are aftermarket? If so, next time try the Toyota pads. Maybe you buy them from the dealer and have your mechanic put them on.

Thanks for your comment, RemcoW. These latest ones are verified Toyota pads bought from the dealer. They’ve said they are the best he can get. He is dumfounded as to why they are still squeaking.

Could be your calipers moving slightly and metal on metal rubbing is causing squeak. The calipers float slightly and move relative to the rigidly mounted caliper bracket. The bracket is bolted to the spindle.

Stoveguyy, are the calipers something the mechanic would automatically check when changing the brakes? This might be worth mentioning to him. Thanks!

Ah, I missed the part where you tried OEM pads.

Stove’s right: those calipers could be at issue but one would imagine they look for that. The caliper floats by means of these pins that are supposed to be greased every time.
There is usually a compound that’s supposed to be put in between the pad and these shims. It could also be that they didn’t add that stuff – again, that’s something they are supposed to do.

are the rotors being turned during a pad replacement?

Tell him to replace the OEM shim kit. It’s pricey on a Toyota and not included with the pads. So often they’re reused and not replaced. This would be the first thing I would try.

@eddo, I’m not sure if the rotors are bing turned (by turned do you mean literally or replaced?). @RemcoW, I will ask about the calipers and the compound as well. I assume he’s done that because he’s tried to fix it a number of times, but it can’t hurt to remind him. @TwinTurbo, I will ask the mechanic about the shim kit. Thanks a bunch all!

Reading his comment, I think @twinturbo is likely right on with his assessment so definitely mention that to your mechanic. If Toyota doesn’t include them with the pads, they likely have never been replaced.
Bad shims could easily cause what you’re hearing. That compound I mentioned is supposed to be between the pads and the shims to stop squealing but if the shim is misformed, no amount of compound will stop the noise.

Great. I’ll talk to my mechanic about the shim. I’m happy to have something to suggest to him. Thanks!

@sassyCar
either or. Something to get rid of the rotors shine and sheen, and give the new pads something to grip better too.

the anti-squeak compound or shims is much more likely, but I have seen glazed over rotors cause a squeal under braking. :slight_smile:

@sassyCar what @eddo meant is . . . did your mechanic machine the brake rotors? I have rarely had brake squeaks after machining/replacing rotors.

Veering off a bit from the rotor or caliper slide servicing (which I agree with) is it possible this squeak could be due to the pedal or pedal linkage itself?

I wonder if this squeak would surface if the pedal were to be depressed repeatedly with the engine running and the car not moving.

Another possibility could be a sway bar bushing squeak due to dry metal on hardened rubber. The intial push of the pedal will nose dive the car a bit and could cause something like this.

Just something for consideration if all else fails. :slight_smile:

I changed pads and 1 of the caliper bolts very slightly started to strip. I was tightening bolt and it just did not feel right. Now when I back up and hit brakes, I get a slight clunk. Too bad the threaded bolt hole is in knuckle. I do not feel like replacing knuckle and don’t think a helicoil type repair would be effective. Perhaps your car is like mine. Maybe it’s karma?

@Stoveguyy clean up those threads with a thread chaser. If the thread chaser won’t give you “new” threads, very carefully use a tap.
So, is the bolt stripped, or just the threads in the knuckle?
If it’s just the bolt, get a brake hardware kit.

@Db4690 I have no idea if he machined the rotors or not. I can definitely ask him about that. So the term is machined or turned. Got it. Also, @ok4450 I have been wondering if it could be something unrelated to the brakes. If all this other stuff doesn’t fix it I will mention the pedal theory. You guys are great! Thanks for the quick help!

I have worked on my Toyota’s for years. I agree that the shims are probably shot (or missing). To save money you can use some “disc brake quiet” on the back of the pads. It is a gooey, rubbery substance that dries to a flexible substance. This stuff keeps the pads from vibrating and squeaking just as well as the factory shims. When you go to replace your pads the next time the stuff easily peels off of the calipers and pistons.

Some aftermarket pads have shims pre-installed (Akebono, Wagner, and even part store house brands at the high end). These seem to work pretty well but I still use some of my “disc brake quiet” compound because I HATE squealing brakes.

Hey Sassycar,

While reading through your post I didnt happen to notice if you said the original pads lasted 30k or more miles between the change to the OEM. Nor did I hear mention if the pads stopped squeaking after a certain extent of time if they did last that long. The reason why i bring this up is because all new pads contain a coating to them right out of the box. The reason for the coating is because when you install the new brake pads you are supposed to take out the car and really wear in the pads to the existing rotors, the coating helps insure propper break in and friction to the rotor. BUT if you dont do this break in proceedure correctly it can cause sqeaking in the brakes. Usualy it stops sqeaking after some miles are put on the pads but it can still feasibly be the problem you are expieriencing. The mechanic installing the new pads is responsible for this break in but sometimes for time reasons they just do a quick trip around the block and it might not be enough.

Food for thought,
Best wishes
Thatoneguy