Chevrolet Silverado / GMC Sierra. Service manual — part 1506

Fig. 4: Identifying J 45101-100 & Lug Nut
Courtesy of GENERAL MOTORS CORP.

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.

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

2008 Chevrolet Silverado 1500

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

Fig. 5: 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

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,

2008 Chevrolet Silverado 1500

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

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

8. If the brake rotor has been REFINISHED or REPLACED with a new rotor, proceed to step

14.

9. If the brake rotor meets the following criteria, proceed to step 10.

The rotor is within specifications and is being REUSED

The rotor has NOT been refinished

The rotor does NOT exhibit thickness variation exceeding the maximum allowable
level

2008 Chevrolet Silverado 1500

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

Fig. 6: Mounting Dial Indicator To Measure Lateral Runout
Courtesy of GENERAL MOTORS CORP.

10. Mount a dial indicator, J 45101 , or equivalent, to the steering knuckle and position the

indicator button so it contacts the brake rotor friction surface at a 90 degree angle,
approximately 13 mm (0. See Special Tools.5 in) from the outer edge of the rotor.

11. Measure and record the assembled LRO of the brake rotor.

1. Rotate the rotor until the lowest reading is displayed on the indicator dial, then set the

dial to zero.

2. Rotate the rotor until the highest reading is displayed on the dial.

3. Mark the location of the high spot relative to the nearest wheel stud, or studs.

4. Measure and record the amount of LRO.

12. Compare the brake rotor assembled LRO to the following specifications:

Specification - JD9, JH6, JH7 Front and JH6, JH7 Rear: Brake rotor maximum
allowable assembled lateral runout: 0.13 mm (0.005 in)

Specification - JF3, JF7 Front: Brake rotor maximum allowable assembled lateral
runout: 0.05 mm (0.002 in)

Specification - JD9 Rear: Brake rotor maximum allowable assembled lateral runout:
0.25 mm (0.010 in)

13. If the brake rotor assembled LRO is within specifications, proceed to step 18.

If the brake rotor assembled LRO exceeds the specification, refinish the rotor to ensure true
parallelism, refer to Brake Rotor Refinishing. After refinishing the rotor, proceed to step
14.

14. Mount a dial indicator, J 45101 , or equivalent, to the steering knuckle and position the

indicator button so it contacts the brake rotor friction surface at a 90 degree angle,
approximately 13 mm (0. See Special Tools.5 in) from the outer edge of the rotor.

15. Measure and record the assembled LRO of the brake rotor.

1. Rotate the rotor until the lowest reading is displayed on the indicator dial, then set the

dial to zero.

2. Rotate the rotor until the highest reading is displayed on the dial.

3. Mark the location of the high spot relative to the nearest wheel stud, or studs.

4. Measure and record the amount of LRO.

2008 Chevrolet Silverado 1500

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