frozen brake caliper?
 

so i'm thinking the problem may be a frozen (dying) caliper or piston...

backstory: drove 150 miles in bad rain storms yesterday. drive in the rain from time to time anyway.

for a while now, after it rains the front driver's side brake makes a popping noise when the brake is applied a few times. i always assumed it was just the pad sticking to the rotor.


today, i go to pull out of the parking spot and it makes its usual popping noise, but then when i start to move forward it's a horrible squealing metal on metal noise.

i stop, do a visual look-see and the pads are still good (they have about 6k miles on them at this point). i notice the rotor has a ring of rust on the outside and inside but clear in the middle. the passenger side rotor does not.

i get back in, pump the brakes a few times, put it in reverse and the noise is gone. drive 5 miles back to the house and no noises / popping...

i'm thinking the pad it just sticking to the rotor because of the rust, but it could also be a piston not releasing pressure on the pad...

I had a similar problem yesterday. Terrible metal on metal squeal, in the parking garage downtown, coming from left rear, and after driving a bit it went away. Will pull the wheels this weekend (not going to drive it further until I do). How does one check to see if a caliper piston is seizing or going bad?

Check the rotor with the ridge for thickness, it may already be below specs.

my problem is solved. Pulled the wheel, and the rotor wasn't turning very easily at all (car in the air on lift bars and in N). Thought maybe a stuck piston in the caliper. Pulled the shoes out and everything was fine - no stuckmopen pistons. As I rotated the rotor, I could hear the squeal. E-brake shoe was hanging up. Pulled the rotor, and the e-brake shoe disintegrated. Caliper is fine. Fix will be pretty simple. Replace e-brake shoes both sides, adjust, add new rear brake shoes WYAIT, and button it back up.

This week my collegaue experienced a bang, then a metal to metal squeal from the front right wheel of his BMW. The sound varied in intensity when driving.

We pulled of the wheel and wiggled the heat shield, and there was a small rock stuck between the shield and the rotor.

Seriously? He heard a bang, a loud squeal, and yet kept on driving. Darwinism at its finest. :rolleyes:

You and your pal make a good pair.

:D hehe

Had to drive and break to see which side was making the squeal.