Loud squeak from braking?

[v_tofu]

Just wondering what this could be?

I hear a loud squeak from my brakes. However, I'm pretty sure it isn't my brake pads. Had a friend look at it and says there's still plenty left on them.

I only hear the squeak when I'm almost completing a full stop, and only seems to happen occasionally. Usually happens when I'm at a stop, and ease off the brakes to inch forward in traffic. I'm guessing it could be the rotor? Seems to happen on one particular spot (ie. squeaks, wheels do a full rotation, then squakes again). Will be taking it to my mechanic to see what the problem is. Sigh.. this after I find I'm leaking some kind of fluid too.:mad:

 

[Davebert]

Just wondering what this could be?

I hear a loud squeak from my brakes. However, I'm pretty sure it isn't my brake pads. Had a friend look at it and says there's still plenty left on them.

I only hear the squeak when I'm almost completing a full stop, and only seems to happen occasionally. Usually happens when I'm at a stop, and ease off the brakes to inch forward in traffic. I'm guessing it could be the rotor? Seems to happen on one particular spot (ie. squeaks, wheels do a full rotation, then squakes again). Will be taking it to my mechanic to see what the problem is. Sigh.. this after I find I'm leaking some kind of fluid too.:mad:

Hi v_tofu, saw your post on RFD and here. The only thing I can think of are the brake pads and shims. I have the same problem with my 78 Triumph Spitfire that does not have shims installed on the front brakes, it would squeak when it just about to come to a stop or if I apply the brakes lightly.

Check to see if your brake pads are not loose and if you have shims to stop the vibration (squeak).

Good luck.

 

[AIMWO4]

Check to see if a backing plate has been bent. I have had a backing plate on my Saab rub the rotor... squeaked at low speed.

 

[v_tofu]

Well, good news is that my mechanic says my brakes are pretty much in great shape as well as the rotors (minus the little bit of rust on one of them).

Bad news is he says theres really nothing I can do about the noise. Said I should try slamming on the brakes a few times, and might work. Not really the solution i'm looking for, but at least I know my safety isnt' at risk!

 

[AIMWO4]

If mine were making a loud noise, I'd pull them off to investigate.

 

[v_tofu]

the noise i hear is very similar to this: http://www.youtube.com/watch?v=i1RaflkDAkU&feature=related

Also, it was suggested i try to bed in the brakes. Hopefully that will work. The rotors and brakes are fairly new, so this may fix the noise.

 

[AIMWO4]

OK. Need a bit more info. Without being able to examine the car in person...

Miles on car
When were brakes changed - by who, - all 4 or just front/rear
Did the person performing the work, open the bleeders to reset the caliper pistons, or push the fluid backwards throught the system?

If you put the parking brake on 3 clicks, does noise still occur?

Have you checked the backing plates for rubbing?

Is it from one side?

Does this happen all the time (Beginning of drive vs. end)?

Can you pull a wheel and take pics?

 

[ljmattox]

"Nothing can be done about the noise"? Tsk tsk.

When I've had this occur in the past, I used a "disk brake quiet" product (comes in tube, bottle, or spray) the point of which puts a high-temp rubbery-like coating on the back of the pad so it can't vibrate against the caliper. Many (most?) pads these days come with a strip of something on the back of the pad for this same purpose. Applying it isn't hard to do, if you can change brake pads yourself.

This link had a pretty readable explanation of brake noise causes and potential remedies:

http://www.aa1car.com/library/tr996.htm

 

[AO928]

The issue is caused by the pad vibrating against the rotor. It a result of the pad design.

The OE pads' leading and trailing edges are at 90 degrees to the face of the rotor. Many aftermarket pads have chamfer or a scallop to prevent this, unfortunately the OE pads don't. And becasue of the price pressures from the vehicle manufactures, often times, NVH testing for brake systems gets minimized or not undertaken. (I used to work for an automotive brake supplier).

You can try taking a file to the pads and putting a chamfer on them or buy new aftermarket pads that have this feature built in.

 

[v_tofu]

miles on car; 42 k

brakes are pretty much new, says Midas

no noise when using e brake

I think its coming form one side, passenger front.

Hopefully I have time to take pics this weekend.

 

[v_tofu]

The issue is caused by the pad vibrating against the rotor. It a result of the pad design.

The OE pads' leading and trailing edges are at 90 degrees to the face of the rotor. Many aftermarket pads have chamfer or a scallop to prevent this, unfortunately the OE pads don't. And becasue of the price pressures from the vehicle manufactures, often times, NVH testing for brake systems gets minimized or not undertaken. (I used to work for an automotive brake supplier).

You can try taking a file to the pads and putting a chamfer on them or buy new aftermarket pads that have this feature built in.

Hi, tried searching for chamfer but not sure what I'm looking for. Would you have a link?

 

[mpvue]

TWO things can cause squeaking:
1. as was mentioned, pad vibration. disc brake quiet on the back of the pad can help limit this.
2. rotor/pad GLAZING. as the word suggests, this is when, after repeated hot/cold cycling, dirt on the pad causes it to glaze over, shiny like glass.

here's what I would do;
take the pads out.
clean them real good, front and back.
run a scotch brite pad over the pad surface and rotor surface to get rid of the shiny glazing.
clean again, w/ brake cleaner.
spray brake quiet on back of pads.
reinstall.
drive to bed in the pads (you can google brake pad bedding procedure) basically involves taking it up to 30 or so, firmly pressing on the brakes down to almost stopped, but DO NOT stop, then repeat a few times.

I GUARANTEE you will not have anymore squeaking.

 

[Davebert]

Hi, tried searching for chamfer but not sure what I'm looking for. Would you have a link?

Here is what they should look like:

 

[v_tofu]

Here is what they should look like:

thanks for the pics. Sorry for the ignorance, but are these chamfers things that go on top of the brakes? Or are they a specific brand of brake pads? Would hate to have to install new brake pads when my current ones technically *work*

 

[Robotazky]

See how the pads in his pics have the corners filed off on the leading and trailing edges? It's a harmonic vibration from the shape of the perfectly smooth surfaces that is causing what you're hearing. My brakes have done that pulling out of the garage, when cold, since the day I bought it. No big deal. Either cope with it or get some better pads, like the pics show. I would not consider that sound abnormal.

One thing that supports the vibration sound hypothesis is that if I leave my car outside when there's a lot of humidity, or after it rains and my rotors don't totally dry off from the heat when I pull in, the tiny amount of rust will sometimes either make it better or worse. All other times, the same exact sound.

 

[Davebert]

thanks for the pics. Sorry for the ignorance, but are these chamfers things that go on top of the brakes? Or are they a specific brand of brake pads? Would hate to have to install new brake pads when my current ones technically *work*

The "chamfer" is the beveled edges on the pads. Your noise problem might be the brake pads vibrating. Your current brake pads might not have those metal shims on the back of the pads. You should try the quiet brake products, apply it on to the back of the brake pads to damp out the vibration. You can get them as a spray or in packs (like a packs of ketchup). I think Canadian Tire carries both version and it should cost under $10. There might not be a need to change out the brake pads.

Noise problems like these are a real nauseous, best of luck in solving this problem.

 

[v_tofu]

The "chamfer" is the beveled edges on the pads. Your noise problem might be the brake pads vibrating. Your current brake pads might not have those metal shims on the back of the pads. You should try the quiet brake products, apply it on to the back of the brake pads to damp out the vibration. You can get them as a spray or in packs (like a packs of ketchup). I think Canadian Tire carries both version and it should cost under $10. There might not be a need to change out the brake pads.

Noise problems like these are a real nauseous, best of luck in solving this problem.

thanks. Picked up a can of "Brake Cleaner"? guy said it should work.

I'll be giving it a try tonight.

 

[AO928]

thanks. Picked up a can of "Brake Cleaner"? guy said it should work.

I'll be giving it a try tonight.

Lemme guess... it didn't work. Brake clean is a solvent for disolving grime and brake dust. That's not what's causing the problem.

The chamfer is the best solution that I know of. Sometimes, the disk brake quiet will help, and having proper lubrication and help too, but in general, it's the chamfer that makes the biggest difference.

On my car, I only get the noise in reverse in the morning - or if it's been raining and the car has been sitting for a few hours. One I pull forward and apply the brakes for a normal stop, if I were to reverse the car and apply the brakes, the sound would be gone.

 

[Robotazky]

Lemme guess... it didn't work. Brake clean is a solvent for disolving grime and brake dust. That's not what's causing the problem.

The chamfer is the best solution that I know of. Sometimes, the disk brake quiet will help, and having proper lubrication and help too, but in general, it's the chamfer that makes the biggest difference.

On my car, I only get the noise in reverse in the morning - or if it's been raining and the car has been sitting for a few hours. One I pull forward and apply the brakes for a normal stop, if I were to reverse the car and apply the brakes, the sound would be gone.

Exactly the same for me.

 

[wmzda5]

I do this every time I change pads, put a chamfer on the edges. This will minimize pads from vibrating. This is old school trick