Why do your disc brakes squeal?

If economically viable, always replace discs if they are warped or excessively worn when replacing your brake pads.

If economically viable, always replace discs if they are warped or excessively worn when replacing your brake pads.

Published Jul 11, 2013

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The last thing you need when applying the brakes after having your car serviced, is to hear your car sounding like a truckload of pigs on their way to the abbatoir, .

This has become the nightmare of most repair centres. And the repair for this brake noise is still in the distant future. The brakes squeal when replaced because the materials used when manufacturing brake pads no longer contain asbestos due to the health hazards it poses.

The friction materials are harder and thus the brake squeal. Some of the brake noise can also be attributed to wear on the brake discs; ideally when changing brake pads, the discs should be replaced as well, but this is both costly and impractical so in most cases only the pads are changed .

So the solution (I use that term far too glibly) for noisy or squealing braodkes is to use a good set of brake pads, and if that doesn’t work try different brands until you find one that works. Or alternatively harass the service centre that fitted the brakes until they resolve your problem.

BRAKE SHUDDER

The other brake problem that is rearing its ugly head more often these days is brake shudder. This happens when you brake sharply in certain instances and a vibration through to the steering wheel.

This can be caused by a few things. The first and easiest to confirm is uneven brake pad and disc wear, when the discs warp and high spots develop on the braking surface. This results in a pulsating feeling on your brake pedal as well as steering judder when stopping. Workshops often try to save the client money by skimming the discs and replacing the brake pads.

This solution only works about 60 percent of the time, however, because more often than not the discs end up below the wear limiton being after skimming, and this can cause the the discs to crack under severe braking, as they operate at very high temperatures.

If economically viable, always replace discs if they are warped or excessively worn when replacing your brake pads.

SUSPENSION WEAR

Then there is the possibility of the worn suspension bushes and lower ball joints. These worn parts can all contribute to brake shudder. On vehicles that still have brake drums and brake shoes at the rear, shudder and squealing can occur when the drums get oval and the shoes are worn.

This can be rectified by having the drums skimmed and the shoes relined. Unlke disks, skimming drums is definitely OK until thay reach their wear limit, at which point the brake drums need to be replaced, along with with the shoes.

With modern cars that have antilock braking systems the problems can get expensive and complicated. So, when you experience any sort of brake problem have it checked out by a repair centre that can handle all repairs to the brake system.

The old adage that you have to learn how to stop before you see how fast it runs, is quite appropriate when discussing brakes. - Star Motoring

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