How to Install Shims for Front Brake Pads

by KevinM

Most automobiles today have front and rear disc brakes. Disc brakes are more reliable and more effective than drum brakes, making them a natural choice for safety-conscious motorists. Disc brakes sometimes generate high-pitched vibrations that result in annoying brake squeal. Adding soft, vibration-absorbing shims to the back of disc brake pads is an effective means of stopping brake squeal. This task is well within the capabilities of the novice mechanic.

Park the vehicle on a firm and level surface. Put a automatic transmission in park or a manual transmission in first or reverse gear. Set the parking. Slightly loosen the lug nuts; jack the vehicle and securely support it on a jack stand. Finish removing the lug nuts and pull off the wheel.

Remove the two caliper-guide-rod bolts. Firmly grip the caliper and roll it back and forth a few times to spread the brake pads slightly. Pull the caliper off the disc and suspend it out of the way on a wire hook or a bungee cord. Be very careful to not kink or stretch the flexible brake line.

Remove any retaining clips that hold the brake pads in the caliper; slide the brake pads out from the caliper. Shims on the backs of the pads should be removed.

Retract the caliper piston with a brake-piston retractor. Place the retractor's spindle-swivel on the piston face; place the retractor's metal plate on the inner surface of the outer caliper frame opposite the piston. Tighten the spindle to force the piston back into the cylinder bore. Be careful not to damage the rubber piston-boot seals.

Apply the shim to the back of the brake pad. Most shims are self-adhesive. Remove the protective paper from the shim's adhesive surface and press firmly onto the back of the pad. The shim should be placed so that the piston contacts the middle of the shim. The shim should not extend beyond the edge of the pad or it will interfere with the pad movement in the caliper. Follow the shim manufacturer's instructions. Apply shims to both pads.

Reassemble the brake by following the same procedure in reverse order. Lubricate the caliper-guide-rod bolts with brake grease before reinserting them into the caliper mounts. Start the vehicle and test the brake operation. Replace the wheel and lower the vehicle.

Items you will need

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