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. Closely inspect 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 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.

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

4. Lateral rotor runout and restricted pads together are the leading cause of uneven brake rotor wear. Therefore, this combination leads directly to brake pulsation.
5. Uniform wheel bolt 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 bolts using a crisscross tightening pattern, even when a torque stick and an air-powered impact gun are used.

CAUTION: DIFFERENT WHEEL BOLTS ARE REQUIRED FOR STEEL AND ALUMINUM WHEELS. IF THE WRONG WHEEL BOLTS ARE USED, THEY MAY LOOSEN AND COME OFF, PERMITTING THE WHEEL TO SEPARATE FROM THE VEHICLE. TO HELP AVOID PERSONAL INJURY AND VEHICLE DAMAGE, ALWAYS VERIFY THE CORRECT WHEEL BOLT AND WHEEL COMBINATION IS USED.

6. Install wheel bolts and tighten in a star pattern.
6.1 Hand tighten all five wheel bolts.
6.2 Use a torque wrench to initially tighten wheel bolts using a star pattern.
Torque: Wheel Bolts (Initial Torque): 63 Nm (46 ft. lbs.)
6.3 Use a torque wrench to final tighten wheel bolts using a star pattern
Torque: Wheel Bolts (Final Torque): 125 Nm (92 ft. lbs.)
7. After rotors/drums and brake pads/shoes have been replaced, proper break-in promotes both longer life and quieter, smoother brake operation. To obtain proper break-in, follow this procedure:

BREAKING IN NEW BRAKE PADS AND NEW BRAKE SHOES
Proper break-in of new brake pads and new brake shoes promotes both longer brake life and quieter, smoother brake operation. To obtain proper break-in, follow this procedure:
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.