When you press the brake pedal, fluid is forced through lines that run to each wheel. The pressure of the fluid forces brake pads to push against a brake rotor, causing friction that slows the wheel and, consequently, the vehicle. On vehicles with rear drum brakes, the fluid forces shoes against a drum, but the effect is the same—friction slows the turning of the wheel. And now that you know the basics, here are five big questions you may have.
Why do brakes need to be inspected or replaced?
Because their performance is dependent on friction, the parts involved with that action wear down. The friction material on the pads and shoes wears away, and the rotors and drums can be damaged by worn pads/shoes or warp under hard use and the heat generated by the friction. Maintaining and replacing those parts when necessary cannot be ignored, because the longer you drive with worn or inadequate brakes, the worse the performance will get—and it may just prove more expensive when you finally take action.
The brakes shudder and shake when I step on the pedal. What’s wrong?
The disc rotors could be warped, creating an uneven surface as the pads try to “grab” them when stopping. Even if that’s not the cause, shaking and shuddering under braking can affect braking performance and the condition should be examined immediately.
I heard a squealing sound for a while, but it went away. Does that mean the brakes are OK again?
No! The squeaking/squealing sound was caused by wear indicators built into the disc brake pads as they rubbed against the disc rotor. That means there was only about 1/16 inch /1.6 mm of pad material left. “Burning” through the wear indicators so they no longer make noise (because they were worn away) means you have less than 1/16 inch /1.6 mm of pad material to stop your vehicle. Have the brakes inspected immediately*!
Why is it more expensive to repair the brakes if I wait a while?
That’s not always the case, but here’s what happens the longer you wait between brake services: As the pads wear beyond their usable life, they can dig into the disc rotors or drums, damaging them enough to require replacement. Severely worn brake pads can also require more work to remove them from the calipers and may require the calipers to be replaced. With regular inspections, you may only have to make periodic pad or shoe replacements, which is typically much less expensive than replacing the pads, rotors and calipers.
But aren’t all brake jobs expensive?
They don’t have to be. Replacing only the pads when they’re worn can prolong the life of other brake components, such as the rotors. There’s never a bad time to have your brakes inspected. Your ACDelco-affiliated Professional Service Centre can check the condition of the brakes and measure the life left in the pads. Your technician can also suggest a variety of value-priced ACDelco Advantage, Professional and GM Original Service Equipment brake parts options to fit your budget.
REMEMBER: If your brakes are shuddering, shaking, squealing or making a grinding sound when you step on the pedal, have them inspected immediately. It’s your safety at stake.