Car Brakes Squeak - Why

Forums › Transport (cars, bikes and boats) › Car Brakes Squeak - Why - How to Fix?

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#2629153 2-Jan-2021 09:09

Shindig:

Are rotors the discs? Just different terminology for them?

Might be a job in the new year for my local garage to take a look at?

If your local garage is the same garage that failed to fix the problem previously, then I’d suggest not using them. Ever again.

Brakes are just about your single most important factor in driving safety. A former F1 driver & multiple Le Mans winner once said to me “You can only go as fast as you can stop”. Obviously there is something wrong with your brakes - they would not squeal otherwise. Your braking performance is hindered, your likelihood of catastrophic braking failure is substantially higher than a vehicle without this problem.

How are you going to feel if that squeal causes a failure under emergency braking because a kid has run onto the road chasing their ball? Yes, unlikely, I know. But far more likely than if your brakes weren’t faulty. Get it fixed. If they aren’t repaired properly, take the vehicle back there until the job is done correctly.

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#2629219 2-Jan-2021 10:08

1024kb:

If your local garage is the same garage that failed to fix the problem previously, then I’d suggest not using them. Ever again.

Brakes are just about your single most important factor in driving safety. A former F1 driver & multiple Le Mans winner once said to me “You can only go as fast as you can stop”. Obviously there is something wrong with your brakes - they would not squeal otherwise. Your braking performance is hindered, your likelihood of catastrophic braking failure is substantially higher than a vehicle without this problem.

How are you going to feel if that squeal causes a failure under emergency braking because a kid has run onto the road chasing their ball? Yes, unlikely, I know. But far more likely than if your brakes weren’t faulty. Get it fixed. If they aren’t repaired properly, take the vehicle back there until the job is done correctly.

Based on what has been already posted describing the issue I think the comment I've highlighted is a tad extreme. The brakes are working normally but with a squeal when under light braking. I'd suggest there is no risk of catastrophic braking failure. In my experience this sort of noise has no impact on the efficacy of the brakes. It is just very annoying.

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Nate001

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#2629226 2-Jan-2021 10:14

What are your breaking habits? Do brake lightly or heavily?

Does it start squealing at the slightest braking pressure?

A build up of break dust can cause the squealing, but as others said if you brake harder it will clear it. I wouldn't go as far as saying its catastrophic...

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#2629238 2-Jan-2021 10:46

Yes a bit of hyperbole to say you're at high risk of brake failure if you've got brake squeal. A stone would have been picked up as the issue or been removed when the rotors/pads were replaced.

Did they do both the front and back when replaced? If you can get it to happen on demand, i'd ask to take a mechanic for a ride to show them the issue yourself.

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#2629239 2-Jan-2021 10:46

Technofreak:

Based on what has been already posted describing the issue I think the comment I've highlighted is a tad extreme. The brakes are working normally but with a squeal when under light braking. I'd suggest there is no risk of catastrophic braking failure. In my experience this sort of noise has no impact on the efficacy of the brakes. It is just very annoying.

You understand what brakes do eh?

OP has brakes that squeal so loud that people turn to see what’s causing the noise. It’s a long term problem that at least one garage has failed to fix.

Also, OP has no idea of vehicle mechanics. Good on them for asking for advice.

Nothing wrong apart from the noise being annoying you reckon? Do you think that if everyone was deaf, there wouldn’t be anything to worry about? It’s more an issue with our ears?

If there’s anything wrong with any item, it is at a far higher risk of failure than the same item in perfect condition. When you’re talking about brakes on a vehicle...

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#2629265 2-Jan-2021 12:19

1024kb:

You understand what brakes do eh?

OP has brakes that squeal so loud that people turn to see what’s causing the noise. It’s a long term problem that at least one garage has failed to fix.

Also, OP has no idea of vehicle mechanics. Good on them for asking for advice.

Nothing wrong apart from the noise being annoying you reckon? Do you think that if everyone was deaf, there wouldn’t be anything to worry about? It’s more an issue with our ears?

If there’s anything wrong with any item, it is at a far higher risk of failure than the same item in perfect condition. When you’re talking about brakes on a vehicle...

Don't get all defensive. You talked about the squealing potentially leading to a catastrophic outcome. I and other posters have said that this is most unlikely.

The squealing can be caused by several things, including severely worn pads which is probably the worst scenario. Based on the fact the vehicle has new pads and or new rotors or skimmed rotors it's reasonable to discard this as the cause. Even so the brakes would not fail completely their efficiency would just become degraded and they'd make a horrible rumbling noise every time you applied the brakes.

The most likely causes are stones or incorrectly fitted anti squeal/anti rattle shims. Neither of which are going to cause brake failure. They can make an unholy noise but the brakes work as intended. To say there is a far higher risk of failure or say this could lead to a catastrophe is just scare mongering. I'd want to get it fixed ASAP but I sure wouldn't be worried about imminent failure.

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#2629274 2-Jan-2021 12:44

I think loud squealing under light braking that disappears completely under hard braking is more annoying than anything catastrophic.

It's just one of those things when you have two surfaces rubbing on each other sometimes you find a perfect harmonic match. Or a stone.

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#2629275 2-Jan-2021 12:46

When someone says you can only go fast as you can stop, it's usually the tyres that stop you not the brakes, contrary to popular belief.

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#2629523 2-Jan-2021 20:59

Batman: When someone says you can only go fast as you can stop, it's usually the tyres that stop you not the brakes, contrary to popular belief.

umm with out the brakes the car is only going to coast to a stop.

the tyres will determine how fast you can stop

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#2629524 2-Jan-2021 21:03

to the OP try a few hard and i mean hard stops from 80-100 down to 20-30, hard enough for the ABS to engage if your car has it or just to the point where the wheels are about to lock up.

also try going about 30kph in reverse and braking hard, if there is something stuck in there this could help dislodge it as its going the opposite way it normally goes.

also as mentioned, might want to see if there is any anti sequel compound on the back of the shims. but in saying that i never use it and have never had issue with it.

Could also be seized sliders.

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#2629707 3-Jan-2021 13:01

In earlier years I solved this issue by removing the pads when they started squealing and filing a small bevel on the leading edge before replacing them. I don't know if it was the bevel or the fact I had cleaned all of the dust off them. Intervals varied between a few weeks to a few months. I was doing high mileages and it was important that the brakes were quiet (else upset paying passengers).

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#2629736 3-Jan-2021 15:18

The local garage didn't replace the discs\pads and they are a good bunch of guys.

The squeak comes on when applying light breaking and I'm quite a conservative driver, and coast rather than break heavy (where possible) where I see the traffic slowing up ahead.

cheers

The little things make the biggest difference.

wally22

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#2629741 3-Jan-2021 15:32

There is a possibility that your pads are glazed if you always brake lightly and drive conservatively. Not criticising, that is the way to drive economically.

Were the pads bedded in at all when new? If not, or if you don't know then it could be an idea to remove the pads, sand them lightly by hand with emery paper, then reinstall and go through the bed in procedure.

EDIT: Did your garage do this already? :

Alternatively try some short heavy braking while applying power (about 50m at a time). A little similar to what Jase2985 suggested. Use a clear road or a private road for safety!

Its quick and not 100% as effective but saves removing the pads.