Chevrolet Silverado / GMC Sierra. Service manual — part 1528

Fig. 55: Identifying J 45101-100 & Lug Nut
Courtesy of GENERAL MOTORS CORP.

1. Remove the J 45101-100 and the lug nuts that were installed during the assembled LRO

measurement procedure. See Special Tools.

2. Inspect the mating surface of the hub/axle flange and the brake rotor to ensure that there are

no foreign particles or debris remaining.

3. Index the brake rotor in a different orientation to the hub/axle flange.

4. Hold the rotor firmly in place against the hub/axle flange and install one of the J 45101-100

(1) and one lug nut (2) onto the upper-most wheel stud. See Special Tools.

2008 Chevrolet Silverado 1500

2008 BRAKES Disc Brakes - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

5. Continue to hold the rotor secure and tighten the lug nut firmly by hand.

Fig. 56: Installing All J 45101-100s & Lug Nuts
Courtesy of GENERAL MOTORS CORP.

6. Install the remaining J 45101-100 and lug nuts onto the wheel studs and tighten the nuts

2008 Chevrolet Silverado 1500

2008 BRAKES Disc Brakes - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

firmly by hand in a star-pattern. See Special Tools.

7. Using the J 39544-KIT , or equivalent, tighten the lug nuts in a star-pattern to specification,

in order to properly secure the rotor. See Special Tools. Refer to Tire and Wheel
Removal and Installation .

8. Measure the assembled LRO of the brake rotor. Refer to Brake Rotor Assembled Lateral

Runout Measurement.

9. Compare the amount of change between this measurement and the original measurement.

10. If this measurement is within specifications, proceed to step 14.

11. If this measurement still exceeds specifications, repeat steps 1-9 until the best assembled

LRO measurement is obtained.

12. Matchmark the final location of the rotor to the wheel studs if the orientation is different

than it was originally.

13. If the brake rotor assembled LRO measurement still exceeds the maximum allowable

specification, refer to Brake Rotor Assembled Lateral Runout Correction.

14. If the brake rotor assembled LRO is within specification, install the brake caliper and

depress the brake pedal several times to secure the rotor in place before removing the J
45101-100 and the lug nuts. See Special Tools.

BRAKE ROTOR ASSEMBLED LATERAL RUNOUT CORRECTION - ON VEHICLE LATHE

Tools Required

J 45101-100 Conical Brake Rotor Washers. See Special Tools.

Correction

CAUTION: Refer to Brake Dust Caution .

IMPORTANT:

Brake rotor thickness variation MUST be checked BEFORE
checking for assembled lateral runout (LRO). Thickness
variation exceeding the maximum acceptable level can cause
brake pulsation. Refer to Brake Rotor Thickness Variation
Measurement.

Brake rotor assembled LRO exceeding the maximum
allowable specification can cause thickness variation to
develop in the brake rotor over time, usually between 4 800-
11 300 km (3,000-7,000 mi). Refer to Brake Rotor Assembled

2008 Chevrolet Silverado 1500

2008 BRAKES Disc Brakes - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

1. Ensure that the caliper and caliper bracket that are already being supported, are clear from

contacting any rotating components, such as the brake rotor.

2. Remove the J 45101-100 and the lug nuts that were installed during the assembled LRO

measurement procedure and/or the indexing correction procedure. See Special Tools.

3. Inspect the mounting surface of the hub/axle flange and the brake rotor to ensure that there

are no foreign particles or debris remaining.

4. Set up the lathe, following the manufacturer's instructions.

5. Refinish the brake rotor, following the brake lathe manufacturer's instructions.

6. After each successive cut, inspect the brake rotor thickness. Refer to Brake Rotor

Thickness Measurement.

7. If at any time the brake rotor exceeds the minimum allowable thickness after refinish

specification, the brake rotor must be replaced. After replacing the rotor, proceed to step
10.

8. After refinishing the brake rotor, use the following procedure in order to obtain the desired

non-directional finish:

1. Follow the brake lathe manufacturer's recommended speed setting for applying a non-

directional finish.

2. Using moderate pressure, apply the non-directional finish:

If the lathe is equipped with a non-directional finishing tool, apply the finish with
120-grit aluminum oxide sandpaper.

If the lathe is not equipped with a non-directional finishing tool, apply the finish
with a sanding block and 150-grit aluminum oxide sandpaper.

3. After applying a non-directional finish, clean each friction surface of the brake rotor

with denatured alcohol, or an equivalent approved brake cleaner.

9. Remove the lathe from the vehicle.

10. Measure the assembled LRO of the brake rotor. Refer to Brake Rotor Assembled Lateral

Runout Measurement.

11. If the brake rotor assembled LRO measurement still exceeds the maximum allowable

specification, refer to Brake Rotor Assembled Lateral Runout Correction.

12. If the brake rotor assembled LRO is within specification, install the brake caliper and

depress the brake pedal several times to secure the rotor in place before removing the J
45101-100 and the lug nuts. See Special Tools.

BRAKE ROTOR REFINISHING

Lateral Runout Measurement.

2008 Chevrolet Silverado 1500

2008 BRAKES Disc Brakes - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado