What causes break whistle?
Discussion
1. Disc brakes have a natural tendency to squeal.
2. Manufacturers have specialist engineers who put a lot of time and effort into specifying materials which don't squeal.
3. Aftermarket suppliers don't have the time or money to replicate all that R&D. They just chuck something together which will fit the car and be fairly cheap. Often they squeal.
4. Best way to avoid the problem is to buy OEM. (Both discs and pads)
2. Manufacturers have specialist engineers who put a lot of time and effort into specifying materials which don't squeal.
3. Aftermarket suppliers don't have the time or money to replicate all that R&D. They just chuck something together which will fit the car and be fairly cheap. Often they squeal.
4. Best way to avoid the problem is to buy OEM. (Both discs and pads)
HustleRussell said:
Resonance.
^ ^ This. Technically, it's when the static co-efficient of friction slightly exceeds the dynamic co-efficient of friction. This effectively causes the pads to grip and then slide many times per second, moving the tiny amount allowed by clearance between pad and caliper. If this frequency is within the range of human hearing, it is heard as a squeal, or occasionally on larger slow-moving discs, as a groan.Ozzie Osmond said:
1. Disc brakes have a natural tendency to squeal.
2. Manufacturers have specialist engineers who put a lot of time and effort into specifying materials which don't squeal.
3. Aftermarket suppliers don't have the time or money to replicate all that R&D. They just chuck something together which will fit the car and be fairly cheap. Often they squeal.
4. Best way to avoid the problem is to buy OEM. (Both discs and pads)
Must remember to mention this to local Mazda dealership as brake squeal has occurred after they serviced OH's RX8 (owned since new).2. Manufacturers have specialist engineers who put a lot of time and effort into specifying materials which don't squeal.
3. Aftermarket suppliers don't have the time or money to replicate all that R&D. They just chuck something together which will fit the car and be fairly cheap. Often they squeal.
4. Best way to avoid the problem is to buy OEM. (Both discs and pads)
Ozzie Osmond said:
Although it's sometimes recommended as a "bodge fix", copperslip shouldn't be needed if the brakes have been properly engineered.
Not strictly true. You cannot engineer for every situation, and even something like a build-up of brake dust on the caliper or the thinning of the brake linings can cause the system to hit a resonant frequency. I've known brakes to develop a squeal that lasts for weeks/months and then subsides again, or comes and goes depending on ambient temperature.GrumpyV8 said:
Must remember to mention this to local Mazda dealership as brake squeal has occurred after they serviced OH's RX8 (owned since new).
Newly replaced pads can sometimes start to squeal if the brakes are only used lightly. I think this lets small areas of the pad surface polish or "glaze" while other areas aren't contacting the disc at all. I've had this issue myself and resolved it by taking the car out on a run with some heavier stops from speed. No problems since then.Here's someone else's experience reported on a Mercedes forum,
"You need to go out & give 'em a hard time.
So, get out on a deserted bit of road, & do 10 hard brakings from 60MPH to 5MPH, in quick succession...but DO NOT STOP. After you've done this drive normally for 5-10 minutes to give the brakes time to cool down, & you should be OK.
Give it a go & let us know how you go.
This is a common issue with brakes that haven't been used hard enough.
Cheers, Pickles."
Read more: http://mbworld.org/forums/c63-amg-w204/464607-oem-...
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