Rear brake problem

[stevetatro]

Question. After my car's been sitting out all day, and everything's nice and cold, I get a low-pitch squeaking sound from one of my rear brakes, without even hitting the pedal. After a couple of stops, the squeal goes away, but I assume the pad is still contacting the rotor when I don't want it to.

Funny thing is that it squeaks once every wheel rotation, as if the rotor is warped or something. I can't believe the REAR rotor would warp, but I'm seeking opinions here.

So, what would cause the pad to be rubbing the rotor? Also, why would it only do this once every rotation?

Thanks.

 

[SHOfun 93]

Steve,
Sounds like a sticking caliper. Remove the caliper pin, relube, and reinsert. Visually inspect the rotor and pad for wear. Put wheel back on. Enjoy squeak free ride. thumb

 

[stevetatro]

I agree, and hope it's just a sticky pin.

Doesn't it seem strange that it squeaks once each tire rotation? It seems if the caliper wasn't releasing and it was rubbing the rotor, it would be a constant squeak.

That's why I asked about the rotor. I've never heard of problems with warped REAR rotors, but it seems I may have one!

Thanks.

 

[wild01ride]

Maybe you're already way past this stage, but a wear indicator that is just starting to make contact will make a sound like that too. Unless you've got slotted/cross-drilled's there will probably be some level of warpage and when those initial couple of microns of wear indicator contact interface with the runout of the rotor, you can get that noise no problem.

Good luck!

 

[billyshoe]

It is more common than one may expect that the brake line closes up allowing flow in the caliper with a pump of the foot then holding the fluid in the caliper with restricted flowback. A good indication of this is a piston that is real stiff to turn back in.