Brake Disc Run-Out Check And Correction

WARNING: This page is about a different car, the 2006 Mitsubishi Montero. However, it is still accessible from the selected car via links, so may be relevant.

Remove the caliper support; then raise the caliper assembly upward and secure it with a wire.
Inspect the disc surface for grooves, cracks and rust. Clean the disc thoroughly and remove all rust.
Fix the disc with a hub nut temporarily.
Place a dial gauge approximately 5 mm (0.2 inch) from the outer circumference of the brake disc, and measure the runout of the disc.
Limit: 0.06 mm (0.002 inch)

Fig 1: Checking Run-Out Of Brake Disc
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
If the run-out of the brake disc is limit value or more, correct it as follows:
1. Place a mating mark on both the wheel stud and disc with chalk where the run-out is greatest.
2. Remove the brake disc. Then place a dial gauge as shown in the illustration, and then move the hub in the axial direction and measure the play.
  Limit: 0 mm (0 inch)
3. If the play exceeds the limit, disassemble the hub and knuckle assembly to check each part.
4. If the play does not exceed the limit, install the brake disc at a different phase, and then check the run-out of the brake disc again.
  
  Fig 2: Checking Hub Play
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
  CAUTION:
  - After a new brake disc is installed, always grind the brake disc with a on-car type brake lathe. If this step is not carried out, the brake disc run-out will exceed the specified value, resulting in judder.
  - When the on-car type lathe is used, first install a M12 flat washer on the stud bolt in the brake disc side according to the figure, and then install the adapter. If the adapter is installed without a M12 flat washer, the brake disc rotor may be deformed, resulting in inaccurate grinding.
  - Grind the brake disc with all wheel nuts diagonally and equally tightened to the specified torque 100 N.m (74 ft-lb). When all numbers of wheel nuts are not used, or the tightening torque is excessive or not equal, the brake disc rotor or drum may be deformed, resulting in judder.
  Fig 3: Installing Washer
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
If the run-out cannot be corrected by changing the phase of the brake disc, replace the brake disc or turn rotor with an on-car type brake lathe ("Accuturn-8750" or equivalent).