Torque Shop

I did not drive my car for two months during the circuit breaker, but I started the engine every week to make sure the battery was working. But when I drove the car for the first time earlier this month, the brakes felt odd. They juddered when I braked, but the issue went away after I braked a few more times. My car has disc brakes all round. What happened?

Keeping a car stationary for several weeks will definitely cause some temporary changes on different parts.

For brakes, the discs would have developed a layer of surface corrosion. This happens even overnight, especially if it has been raining.

The surface corrosion is not something to be overly concerned about.

The shiny friction surface of all brake discs - the exceptions are those with a titanium surface coating or those made of carbon-ceramic - will corrode as long as the car is left standing and there is sufficient atmospheric humidity.

The condition causes no permanent damage and does not require a visit to the workshop.

The corrosion can be cleared by driving for a short distance and applying the brakes gently and gradually.

During this time, the brake pedal will feel a little lethargic, while braking will be noticeably less effective. The car may require longer braking distances than what you have been used to and, in some cases, there may be a little juddering for a while.

Besides disc corrosion, it is also common to have sticky brake pads or shoes (on drum brakes).

In this case, even though you may have released the parking brake using the handbrake lever or via an electronic switch as in many modern cars, the adhesion between the brake pad and disc prevents a full release. Hence, you might find that the car is reluctant to move.

This is also not something to be too worried about.

The adhesion is temporary and will eventually break, sometimes accompanied by a thud when you start moving off.

What is important to note is this: If you are driving your car after it has been left stationary for some time, you have to exercise some restraint at least for the first 5km to 10km where your brakes may not be in their optimal working condition yet.

A version of this article appeared in the print edition of The Straits Times on June 27, 2020, with the headline 'Torque Shop'. Subscribe