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Horrible squealing sound when braking

Since this past autumn when the weather became colder (I live in Washington, D.C.), my 2000 Saab 9-3 convertible has developed an obnoxious habit of “screeching” – imagine nails on a chalkboard amped up with a hundred times more decibels.

Two separate mechanics have confirmed that the car is in great shape and needs no work (yes, they actually said “you don’t need us to work on it,” can you believe that?). With the first mechanic sending me to the second, the second said he thinks there is some “rust on the trim” of the brakes, causing the squealing sound when I brake. He said I need to “burn it up more” on the road, i.e. drive it fast and hard. I’ve done this for about two months, and things have not improved, even as the weather has warmed up.

Yes, this car is driven daily in the city, though I am a bit of a cheapskate pretending to be an environmentalist, i.e. I coast as much as possible to avoid unnecessary gas usage, especially between stop signs and into red lights.

To be clear, the sound is deafening, especially with the top down, and makes pedestrians cringe and throw me “this is why cars are evil” looks from the street.

Any thoughts on what I can do to fix this horrific sound, or is my car doomed to future status as a foley artist’s prop for an Exorcist sequel?

P.S. The brake pads are new and both mechanics said they are not the issue.

So, the sound only happens when you depress the brakes?
Did this start when the “new” pads were put on or was it there before this?

Brake pads are not all the same. They can be made of different materials and also differ in “hardness”. If the pads are not installed correctly they can squeal, and some retaining clips and hardware can affect noise too.

It sounds like they installed hard pads on your brakes. The harder pads last longer but also wear the rotors more and can make more noise.

If the pads were not installed correctly, or if they are not sized and made to match the caliper the pads can “vibrate” and make noise. Old retaining clips and the hardware that holds the pads in place can “vibrate” also and may need replacing.

It seems that the shop who did the work is trying to get you to live with the problem rather than either redo the job or find the source of the noise and correct it.

Thanks to JSutter and to UncleTurbo for following up to my question.

To answer JSutter’s question, the problem began about 3-4 months after the new brake pads were put on. The second mechanic pointed to rust along the outside of the rotor, and said this was weather-related, and that I needed to drive the car “harder” (faster and for longer stretches) to burn off the rust.

Not sure if this is or isn’t accurate, and not sure if there are alternatives such as scraping rust off with a brillo pad or something along those lines. Neither mechanic installed the brake pads – was done by previous owner just before I purchased the car. It runs great and is functionally sound save for this screeching sound.

Any rust effecting the rotors should be burned off in the first few miles.

Could be inappropriate pads (OEM pads are a safer (but not foolproof) choice for reducing sqeal), or they may be glazed, needing sanding or replacement. I doubt the rust theory, all disks rust to some extent.

Define “driving harder”? I suspect the mechanic was telling you to get the car up to highway speeds and in a safe area perform several “hard” stops, meaning you’ve got to press on the brake petal hard and stop the car fast. The point of this is to burn off the “glaze” caused by dirt and debris that may be accumulationg on your brake pads. Not sure if this is what he meant, but try a few hard stops and see if you notice any difference.

At this point the pads could be beyond saving and the answer is to install another set of fresh brake pads.