It might be coincidental, but for the last couple weeks, when the temperature went into the low 30's my rear brakes make a scraping sound the first 3 or 4 times I use them and then they behave normally. There's no pulsation or disfunction of any kind just a noise that sounds like cement pouring down a chute. Of course, since it stops after a few applications, it will never happen at the dealer. Any ideas/suggestions?

 

When you car sits in damp weather or even after being washed the night before your rear rotors have light rust on them. wehn backing up out of the drive or pulling away they will make noise and a horrible sound on the first stop or two.

This is common on ever 4 wheel disc car I have owned. It is nothing to worry about and is considered normal.

Since most of your braking is up front they are less effected and the rears are the noise makers.

At present all three of my cars in the garage have 4 wheel disc and all three do this.

 

This is what I call the lucky noise. Some cars have good luck and don't do it others have bad luck and do make the noise. There are different fixes depending on the root cause. But it won't hurt or affect your braking.

 

Look at your brakes before you go anywhere and you will see some light surface rust on the disc face.

Mgr you may not see this much down there but here is is so damp it just takes a few hours to get a light coating of rust on a rotor this time of year.

I even hear my neighbors new Trailblazer do it this AM when he was backing out.

 

OK, thanks guys. I was hoping that was what was going on, seemed to make sense. Funny thing is it was wet at night in the summer some times and that didn't happen. It just did with the near/freezing.

Maybe I'll blow some dust off one of those chemistry or physics college text books over there...


Uhhh.. maybe not.