Torque Shop

What causes brakes to squeal? Is it a sign of worn parts? Should I get it fixed?

There are several reasons why brakes squeal and the noise usually originates from the front.

It is often associated with brake pads that are non-genuine and of a poorer quality. Brake pads are components you do not want to save money on. Always insist on genuine replacement brake pads.

But if the brakes squeal even though the pads are original, you should investigate further.

Within each disc brake assembly are thin metallic plates on the backing of the brake pads. These function as dampers to quell any vibration that can cause noise. For this reason, they are commonly called "anti-squeal shims".

Often, new shims are included with the new pads. While there may not be any adverse effect on braking performance if the shims are not fitted during brake pad replacement, you will eventually begin to hear squealing if they are absent.

Also necessary during brake pad replacement is a thorough clean-up. A build-up of brake dust around the callipers can lead to noise.

Some callipers have mounting components such as pins and clips. These should also be replaced if worn. Most parts are inexpensive, so getting a complete set is worth the effort.

Usually, a visual inspection of the pads is sufficient to determine if pads are worn. But modern cars have a warning light to indicate worn brakes.

On some older cars, a small spring embedded in the pad makes contact with the disc when the pad wears down. This emits a squeal and serves as a warning that the pads need to be replaced.

Brake squeal is not an indication that failure is imminent, so urgent attention is usually not required. But you should still have it fixed.

Shreejit Changaroth

A version of this article appeared in the print edition of The Straits Times on August 17, 2019, with the headline 'Torque Shop'. Print Edition | Subscribe