Why do brakes squeek?

[Animal Farm Pig]

The question is simple:
What makes brakes squeek? What can I do about it?

[Rainycity]

well theres a mouse in there

[MunkeyQ]

If it's squeaking, the noise is the pads vibrating in the caliper. The solution is to apply copper grease to the back of the pads.

Squeaking brakes can also be caused by contaminated liners - if oil, brake fluid or anything similar gets on them, it gets engrained into the lining and causes it to squeak like a pig being cut with a chainsaw. You can clean the linings with alcohol but it's generally best to replace them.

However, if it's more of a squeaking grind, then it may be worn/damaged pads or a scored rotor. This is much more serious...

[Animal Farm Pig]

Originally Posted by MunkeyQ

If it's squeaking, the noise is the pads vibrating in the caliper. The solution is to apply copper grease to the back of the pads.

Squeaking brakes can also be caused by contaminated liners - if oil, brake fluid or anything similar gets on them, it gets engrained into the lining and causes it to squeak like a pig being cut with a chainsaw. You can clean the linings with alcohol but it's generally best to replace them.

However, if it's more of a squeaking grind, then it may be worn/damaged pads or a scored rotor. This is much more serious...

Awesome. I know mine isn't grinding, so that's good. I doubt that mine are contaminated.

Is applying the grease a fairly simple process? Do I need to take anything apart?

[MunkeyQ]

Originally Posted by Animal Farm Pig

Awesome. I know mine isn't grinding, so that's good. I doubt that mine are contaminated.

Is applying the grease a fairly simple process? Do I need to take anything apart?

You need to remove the wheel and then take out the pads, just like you're changing them.

Put a little grease on the edges where it touches the caliper and reassemble. Don't use normal grease! Make sure it's copper grease.

[Animal Farm Pig]

Originally Posted by MunkeyQ

You need to remove the wheel and then take out the pads, just like you're changing them.

Put a little grease on the edges where it touches the caliper and reassemble. Don't use normal grease! Make sure it's copper grease.

Awesome. Thank you so much.

[Vargus]

Also, the low-brake squeak is caused by a piece of sheet metal that is part of the pad that rubs on the rotor when the pad gets too low. When you apply the brakes it makes quite a racket.

Of course, this isn't always the case. The brakes in my Saturn are squeaking even though the rear shoes are known to be good when I instlled them and I replaced the front pads about a month ago.

Brakes are fucking fickle pieces of shit. >:/

[Nereth]

If memory serves, the physics reason is a self excited vibration that has consistently eluded a good solution.

[Kwinnie Bogan]

HAr HAr HAr

[Echidna]

9/10 times it means your pads are almost at the end of their life. I do not suggest using copper grease or anti-seize anywhere near the brake components. Jack it up, pull the wheel, loosen the two bolts and pull your caliper. Did you replace your pads last? Did you put the shims in behind them? Are they metallic, semi-metallic, ceramic, etc?

[Rocko]

Glazed over rotors can squeak, even when the pads aren't worn. Tends to happen if you put harder-than-factory pads on or do a lot of hard breaking without cooldown time. If the pads aren't worn, do the copper grease thing and get some of that abrasive stuff that you apply to the surface of the pads, that will basically sand the rotors a bit to remove the glaze.

[MunkeyQ]

Originally Posted by Echidna

9/10 times it means your pads are almost at the end of their life. I do not suggest using copper grease or anti-seize anywhere near the brake components.

Eh? That's standard practice. Tell that to a garage, who will have a big pot of the stuff to prevent fasteners from seizing and to stop squealing brakes. It's actually sold in little tubes specially for this:

[Valheru]

^^^^ This

Quite obviously you need to make sure you don't fucking smear it all over the place, but using copper grease is standard practice.

[Echidna]

It might work. I've worked on cars since I could see over the steering wheel and I never heard of that. The only time I've used grease in braking components is with a caliper where one of the sides is a sliding pin, which is greased. I'll keep this in mind for the future though! Op, let me know how if it works.

[Rodrat]

my brakes squeeked from the moment i installed them
sometimes they do sometimes they dont
they work fine on my truck
i think its cause i live on a dirt road and it could be dirt and stuff?

[Valheru]

Originally Posted by rodrat

i think its cause i live on a dirt road and it could be dirt and stuff?

That's very possible. You could get the rotors cut in order to help de-glaze the pads.

[Kwinnie Bogan]

Yeah, was going to say they shoulda been worn or shaved in by the sounds of it.

[Valheru]

Many brake calipers have a little tensioned plate that helps to seat the pad and reduce vibration. After many heating/cooling cycles these plates can lose their temper and cause the pads to start squealing, copper grease or not.

Simply replacing these plates can sort the problem out (until next time, of course). It's just one of those things.

[Valheru]

Many brake calipers have a little tensioned plate that helps to seat the pad and reduce vibration. After many heating/cooling cycles these plates can lose their temper and cause the pads to start squealing, copper grease or not.

Simply replacing these plates can sort the problem out (until next time, of course). It's just one of those things.

[ratfrink]

Originally Posted by Echidna

It might work. I've worked on cars since I could see over the steering wheel and I never heard of that. The only time I've used grease in braking components is with a caliper where one of the sides is a sliding pin, which is greased. I'll keep this in mind for the future though! Op, let me know how if it works.

I used to work in a garage and we always put copper grease on the back of the pads. Even new cars come with grease on them.

Even Haynes manuals say to do it.

It could be the anti-squeal shim like some people have said.

Either way, take a look. If your pads and rotors are fine, dab a tiny bit of grease on the back and replace the shims, if it has some.

[MediumD]

I use this stuff rather than copper grease:


CRC Disk Brake Quiet, like 2 bucks at your local parts store.

Similar results, less messy. Although if you have wheels and calipers that allow you to see the back of the pad, it can look a bit funny...

[MunkeyQ]

Originally Posted by MediumD

I use this stuff rather than copper grease:


CRC Disk Brake Quiet, like 2 bucks at your local parts store.

Similar results, less messy. Although if you have wheels and calipers that allow you to see the back of the pad, it can look a bit funny...

I like copper grease because you can use it on fasteners too. It makes the rapeworthy price slightly better.

And who can say no to sparkling gold goop?

If you have drums and they make a sound like a freight train stopping, chances are you have a severe slave cylinder leak though. Look for the tell-tale streaks of brake fluid on the inside of the tyres.

[ratfrink]

^ for a week or so, the first few times I pressed my brakes they sounded like that, but after that they were silent even under heavy braking.

I meant to check it out, but it stopped doing it.

[bornkiller]

Originally Posted by MunkeyQ

I like copper grease because you can use it on fasteners too. It makes the rapeworthy price slightly better.

And who can say no to sparkling gold goop?

I can't say no to it...copper grease is slimy gold
Excellent on boats, outboards/inboards, wheel studs on boat trailers, the pre anti sieze solution that won't lubricate the wheel nuts off. (unlike any old grease, which is just stupid to put on a wheel stud)