Brake Squeak

[The Critic]

I installed a set of NAPA Adaptive 1 brake pads on the rear axle of my Saturn. This was about 11k ago. When I installed the pads, I also installed new Centric Premium rotors. The new hardware that came with the pads did not fit properly, so I cleaned and reused the old (and slightly worn) hardware.

For the last few thousand miles, I have been getting a light squeak whenever I use the brakes while backing up. I can only reproduce the light squeak if I use the brakes while backing up. I cannot reproduce the squeak during normal braking.

Also, the rear calipers on this car uses a threaded piston. When I screwed the pistons back in, one of the caliper pistons was a bit difficult to screw in, but I'm not sure if I was using the right pattern on the "cube." Since the old pads wore relatively evenly, I decided not to replace the calipers. However, I suspect that there is something wrong with the calipers as my previous set of rear pads only lasted 28k compared to the 90k of the factory pads.

So what should I do? Should I replace the calipers and brackets? Why would the brakes only squeak in reverse?

Thanks.

 

[Corvette Owner]

I can't answer this, but my Nissan Murano also squeeks while backing out of the garage. This is with original pads.

 

[mechtech2]

If the calipers move freely on their properly greased sliders, and all the hardware is good, then I'd simply put anti squeal sauce on the back of the pads. Not lube grease, but the rubbery when dry stuff. Auto parts stores have plenty.

 

[tropic]

Can you isolate the wheel the noise is coming from?

I'm just a pad slap sorta guy, but I'd be curious to see if there's any lateral play with the caliper, like maybe a slightly loose mount bolt, or a piston that isn't withdrawing on a cold start.

I'm not knowledgeable, but I'm curious!

 

[sparkplug]

My Jeep has been doing this for a looong time. Right rear likes to squeal at low speed. Pad and rotor change's helped for about 400 miles then it just comes back. I've just deemed it normal.

 

[The_Jeff]

I wonder if the normal slop in the pad ears forces the rotor one way (innie/outie) going forwards and the other way going backwards. Then it'd be going against its wear pattern, maybe scrubbing that thin ring of rust on the outside of the rotor not normally swept by the pads. I wouldn't worry.

 

[The Critic]

Also, I should mention that there is not an even layer of pad material on the rotor. In other words, the entire rotor surface is not gray with pad material. There are "splotches" and "rings" of it on the surface. It's a bit hard to describe. My friend's Corolla with Raybestos pads does the same thing, for some reason.

 

[Chris142]

Take the pads off and bevel the edges on a bench grinder and re- install them.

 

[The Critic]

Originally Posted By: Chris142
Take the pads off and bevel the edges on a bench grinder and re- install them.

They already came chamfered.

 

[moribundman]

Originally Posted By: The Critic
Also, I should mention that there is not an even layer of pad material on the rotor. In other words, the entire rotor surface is not gray with pad material. There are "splotches" and "rings" of it on the surface. It's a bit hard to describe.


My rotors are only shiny, bare metal without any pad deposits. Do you ride the brake?

 

[The Critic]

Originally Posted By: moribundman

My rotors are only shiny, bare metal without any pad deposits. Do you ride the brake?

I thought you are supposed to have an even layer of pad deposits on your rotors?

Most cars that I see on the road have a dark layer of pad deposits on their rotors.

 

[moribundman]

My cars have always had shiny rotors. I'm not going to overthink this. I guess we Germans like our rotors clean.

All I can say is, on a bicycle, if the pads leave detritus on the rim or disc, brake squeal or chatter is invariably the result.

 

[tom slick]

My rotors are all shiny, never had any with grey deposits.

 

[moribundman]

Michael's car has abnormal brake pad transfer issues.

Rotors are supposed to be free of (visible) deposits. My guess is the pads get too hot, either due to riding the brake, braking too much, or because the brake pad material is unsuitable for Mr Wan's driving style. I wonder if Michael notices tire deposits on the road behind his car all the time.

 

[George7941]

Originally Posted By: mechtech2
If the calipers move freely on their properly greased sliders, and all the hardware is good, then I'd simply put anti squeal sauce on the back of the pads. Not lube grease, but the rubbery when dry stuff. Auto parts stores have plenty.



At one time the blue anti-squeal compound was widely used, I don't see it used as much any more. I thought lubes such as Ceramalube was more effective in controlling squealing. Are you saying that, in your experience, lubes are not very effective in controlling squealing?

 

[moribundman]

I used to use the RTV like anti-squeal type goop/adhesive on the back of the pads for years. I have to add that my car's pads did not have shims and that the (front) pads had an adhesive foam backing. I used the the anti-squeal goop only if I had for some reason to remove the pads. I then removed the damaged original adhesive and replaced it with the anti-squeal goop, which worked effectively. Let me add that per Audi and ATE, the adhesive backing on the pads was not required, but merely optional. My car's service manual stated that a brake lube (for example Plastilube) can be used on the pad backing as anti-squeal, which is what I have always done on the rear pads.

Last time I bought brake pads for my car, the pads came without any adhesive on them. Since it has repeatedly been stated that the anti-squeal goop may impede heat transfer (somewhat, maybe a lot?), I used Ceramlube on the pads backing plate. There is no squeal whatsoever.

 

[mechtech2]

Just put the sauce on the back of the pads. Do it properly, and it won't squeak.

 

[moribundman]

Are you talking to me?