Brake Replacement TimeDecember 2nd, 2013 by Joseph Wright
The primary ways to evaluate brake wear and tear on disc brakes: looking and listening. First, check for deterioration by scanning the brake pads through the spaces between the wheel’s spokes. The outside pad will be pressed against a metal rotor. Usually, at least 1/4 inch of pad should be present. If automobile owners see less than 1/8 inch of pad, they need to have their brake pads checked or replaced.
Ever heard that high-pitched screeching sound when drivers applied their brakes? That is a small metal tab, called an indicator, which is giving an audible warning that drivers need to replace their brake pads. Drivers should be aware of this sound (which is loud enough to be heard while the windows are up, but not necessarily loud enough to be heard over the radio or air conditioner). If heard regularly, they should quickly make an appointment with the mechanic.
One exception is if the vehicle has been sitting after being exposed to water, such as from rain or from washing it. The moisture can cause a thin layer of rust to develop on the brake rotors. This activity is standard. When initially putting on the brakes, the pads pressing on the rust-covered rotors could produce a squeal for a few stops until the rust is worn off and then the sound will soon be gone.
Here are some other signs of brake problems. If vehicle owners hear or feel any of these, they should go to a repair shop as soon as possible:
Fading or declining responsiveness. If brakes are not as responsive as they should be or if the pedal “sinks” toward the floor, this could be a hint of a leak in the braking system. It could be an air leak (in the brake hose) or a brake fluid leak. One sure indicator of a brake fluid leak is a small puddle of fluid when the car is parked. Brake fluid strongly resembles fresh motor oil, but with a less “slimy” texture.
Pulling. If the vehicle “pulls” to one side while braking, it may be a sign that the brake linings are wearing unevenly or that there is uneven pressure being applied in the brake system. The vehicle may need the brake calipers checked or to have the fluid bled for air.
Growling or grinding. This loud metallic noise signals that driving has worn down the pads entirely, most likely beyond replacement. The grinding or “growling” sound is created by the two pieces of metal (the disc and the backing plate of the pad or caliper) rubbing together. This can damage your rotors, creating a uneven surface. If this happens, the mechanic likely will say that the rotors need to be “turned” (a process that evens out the rotor surface), or replaced if the rotor surface is too damaged.
Vibration. A vibration or pulsating brake pedal is often a sign of warped rotors. The vibration can feel similar to the feedback in the brake pedal during a panic stop in a vehicle equipped with anti-lock brakes. It is a sign of warped rotors if the vibration occurs during braking situations when the anti-lock brakes are not engaged. Warped rotors are caused by intense braking over an extended time, such as when driving down a steep mountain or when towing. Tremendous amounts of friction are created in these situations, heating up the rotors. Without a bit of normal driving after these situations the rotor can cool unevenly and cause the rotor to warp. The vibration is felt because the brake pads are trying to clamp on this warped surface. For automobile owners who drive in these conditions, they should make it a point to drive normally after heavy braking situations so their brakes have the needed time to cool off properly.
For many owners, maintaining the vehicle’s brakes is something that is often overlooked. But keeping the brakes properly maintained and in peak working condition can prevent costly repairs down the line and, even more importantly, help drivers avoid a collision.
Joseph Wright is a copywriter with Transamerican Auto Parts in Compton, CA. He has been a professional journalist for over 20 years. He lives in Los Angeles.