The brake calipers perform a very important aspect of vehicle operation. The caliper consists of a housing, piston, dust boot, bleeder valve, and hydraulic flex hose port.
Some of the most common brake system concerns are related to the improper maintenance of the system. The caliper is the last line of defense in stopping, and it's important for you to diagnose problems with them.
Uneven pad wear is usually the culprit when caliper slides stick. As the piston causes friction between the pads, caliper slides allow the housing to move back and forth. As the piston moves out against the pads, the outer casting of the housing squeezes against the outer pad, as the piston pushes against the inner. Acting as a clamp, the proper amount of force is evenly applied to create friction against the rotor, and the tire and wheel assembly should stop smoothly.
Dirty or rusted caliper slides can cause binding of this action, causing uneven force to be applied to the pads, and allow for the uneven wear. When performing a brake job, it is important to remove the slides from the caliper, clean them, and apply a light coating of caliper grease found at any reputable auto parts store. Another simple procedure is when you remove the pads from the caliper bracket, make sure to clean the metal saddles the pads reside in.
Pad saddles can cause the pads to stick if not properly cleaned, causing uneven wear as well. In the most extreme case, the slides and the saddles can be so dirty and rusted, that they won't function at all. At that point it is best to replace the parts; do not take chances with your brake system.
Diagnosing a brake caliper pull is not complicated. The direction of the pull is usually the opposite of the defective part. If you apply the brakes and your vehicle darts to the left, the right-side caliper or hydraulic flex hose is the most likely cause. To determine the defective part, open up the bleeder valve on the caliper housing and then close it off. If the tire and wheel assembly spins freely again, the most likely cause is the hydraulic flex hose. If the tire and wheel assembly does not spin freely, the caliper piston is frozen, and calipers need to be replaced. Always replace hydraulic components in pairs, and follow manufacturer recommendations for proper bleeding procedures.
Keeping the moving parts of the brake caliper clean will improve brake performance and prolong the life of the pads. Neglect, "riding the brakes," and poor judgment in stopping distance are factors in unscheduled brake maintenance. Safety should be the No. 1 concern when performing brake repairs.
