How to Install Front Disc Brakes

The braking system is the most important safety system on any automobile. The engine can accelerate to highway speed in 10 seconds or less, but we ask the brakes to stop the vehicle from that speed in less than half that time. Disc brakes are the most common brakes on today's automobiles since they are more effective and more reliable than drum brakes. Brake maintenance is a routine part of automobile maintenance and car owners can save money by learning how to perform this relatively uncomplicated task themselves.

Instructions

1

Park the vehicle on level ground and engage the parking brake. Partly loosen the wheel lug nuts on one of the front wheels. Raise the vehicle with a jack until the partially loosened wheel is off the ground. Support the vehicle on jack stands. Completely remove the lug nuts and remove the wheel.

2

Remove the two caliper bolts. Roll the caliper back and forth a few times to spread the brake pads slightly. Remove the caliper from the disc and suspend it out of the way using a wire hook, cord or bungee cord. Be careful not to damage the rubber brake hose.

3

Remove the brake pads by removing the retaining springs or clips if any are present. Pry the clips off with a screwdriver or pull them off with pliers, as appropriate. Take care not to damage the clips so that they can be used again when reassembling the brake. Remove the pads by sliding them towards the center of the caliper until they are free.

4

Retract the piston with a brake pad spreader, also known as a brake piston retractor. This tool comprises a small metal plate with a threaded spindle passing through it. The spindle has a knob, handle or hex head on one end and a swivel on the other. Place the metal plate against the inner edge of the outside caliper frame opposite the piston and place the swivel securely on the edge of the piston face. Turn the spindle clockwise to push the piston back into the cylinder.

You can also use a large C-clamp to retract the piston. Hook the clamp's frame end over a solid part of the back of the caliper and adjust the clamp spindle until the spindle swivel rests securely on the edge of the piston face. Slowly tighten the clamp to push the piston back into the cylinder.

5

Measure the brake pad lining thickness with a finely graduated ruler. Replace the pads if the lining thickness is less than the manufacturer's recommended service limit, or if the linings are worn unevenly or damaged. The lining thickness service limit can be found in the vehicle's shop manual or an aftermarket equivalent repair manual. If no manual is available, ask at an auto-parts store.

6

Determine the disc thickness with a brake disc micrometer at six or eight places around the disc(more commonly known as the rotor). Replace the disc if the disc thickness is less than the manufacturer's recommended service limit, or if the disc is warped, cracked, or deeply scored. The disc thickness service limit can be found in the vehicle's shop manual or an aftermarket equivalent repair manual. If no manual is available, examine the outer rim of the disc. The service limit and the disc thickness when new are often stamped into the metal of the outer disc rim. If the disc shows minor damage, it can be refurbished by machining the disc surface. Brake shops and auto-parts stores frequently offer this service for a reasonable price.

7

Follow the steps in reverse order to reassemble the bake. Clean the caliper guide bolts with brake cleaning fluid and then lubricate them well with brake grease before reinserting them in the caliper mounts. Replace the wheel and lower the vehicle. Test the brake operation before driving the vehicle.