Disc Brake System: Service and Repair

INFORMATION ON PERFORMING BRAKE SERVICE

Several important factors are frequently overlooked when performing brake service. The following list must be considered and followed when appropriate:
1. Proper machining of brake rotors is not a simple operation. Make sure the brake lathe is well maintained. Keep it clean at all times. Handle attachment hardware with care. Damaged hardware will not machine rotors or drums accurately. Inspect closely the surface finish of machined rotors and drums. Make sure the cutting tips remain in good condition. Use a dial indicator to make sure rotors turn squarely on the brake lathe.
2. Keep all installed brake parts as clean as possible. Make sure to clean machined brake rotors and brake drums with a spray solvent (Saturn Choke Cleaner P/N 21007127 or Saturn Brake and Choke Cleaner P/N 21007432 or equivalent). Always wipe off machined brake rotor surfaces with a lint-free shop towel after cleaning.
3. Thickness variation of rotors due to wear is a major cause of brake pulsation. Using a micrometer, check for excessive thickness variation whenever a customer comments on brake pulsation.
4. Lateral rotor runout and restricted brake pads, together, are the leading cause of uneven brake rotor wear. Therefore, this combination leads directly to brake pulsation.

IMPORTANT: Make sure calipers slide freely on their pins. Make sure brake pads move freely in their brackets.

5. Uniform wheel nut torque is very important. Uneven torque can distort brake rotors, causing excessive lateral brake rotor runout. A hand-held torque wrench must be used to secure wheel nuts using a crisscross tightening pattern.
Torque: Wheel Nut: 140 Nm (103 ft. lbs.)
6. After rotors/drums and brake pads/shoes have been replaced, proper break-in promotes longer life, smoother braking, and quieter operation. To obtain proper brake-in, follow this procedure:

BREAKING IN NEW BRAKE PADS AND NEW BRAKE SHOES
From 48 to 64 km/h (30 to 40 mph), apply brakes gently until vehicle slows nearly to a stop. Accelerate vehicle back to 48 to 64 km/h (30 to 40 mph) and drive long enough for brakes to cool - 30 to 40 seconds. Repeat this process five times, each time allowing sufficient time between stops for brakes to cool.

Complete the break-in procedure by gently slowing the vehicle from 89 to 32 km/h (55 to 20 mph) four times. Allow 30 to 40 seconds between stops for brakes to cool. This break-in procedure will reduce brake noise and increase brake life and performance.