After taking my car out of winter storage I have noticed that my driver’s side rear brakes are making a metallic whining noise that goes away whenever I put pressure on the brakes. The caliper is an aluminum PBR unit and the rotors/pads only have around 5000 kilometers on them. I have read posts about the iron calipers having a design flaw that allows the pads to rattle around in the caliper and was wondering if that could be my problem. Can somebody help me?

 

Sounds like the pads think they need to be replaced.

The noise is probably the "audible wear sensor", which is a little clip piece of metal on one of the pads that's supposed to contact the rotor when the pads get thin, and alert the driver that something is wrong. They often get bent during shipping or installation, and end up too close to the rotor, and start making their noise long before the pads really need replacing. And, if one of the calipers is stuck on its slides, one pad may be worn down to nothing already.

Just take the wheels off and look at them.

 

The "audible wear sensor" was one of the first things I checked and theres plenty of room in between it and the rotor. This sound is really annoying and embarrassing any other suggestions?

 

Do a panic stop and see if it goes away.


Ed

 

With the back of my car jacked up I started the engine and put the car into gear to make the rotors turn and noticed that there was quite a bit of lateral run out on the rotor. This was causing the pad to grind back and forth against part of the caliper. This is only on the rear driver’s side rotor and not on the opposite side. Is my rotor warped or is there something else that can be making it wobble like this?

 

Did you have the rotor bolted to the axle with a couple of lug nuts? If not, it was just dangling off in space somewhere, not connected to anything, and you can't judge runout like that.

If in fact the rotor has runout when firmly attached to the axle, swap them from left to right. If the runout moves, it's the rotor; if it stays, it's a bent axle.