Hummer H3. Manual — part 1038

Fig. 3: Measuring Brake Rotor Thickness
Courtesy of GENERAL MOTORS CORP.

5. Using a micrometer calibrated in thousandths-of-a-millimeter or ten-thousandths-of-an-inch,

measure and record the scoring depth of any grooves present on the rotor friction surfaces.

6. Compare the groove scoring depth recorded to the following specification:

2007 Hummer H3

2007 BRAKES Disc Brakes - H3

Specification: Brake rotor maximum allowable scoring: 1.50 mm (0.059 in)

7. If the brake rotor scoring depth exceeds the specification or if an excessive amount of

scoring is present, the rotor requires refinishing or replacement.

BRAKE ROTOR ASSEMBLED LATERAL RUNOUT MEASUREMENT

Tools Required

J 39544-KIT Complete Torque Socket Set-10 Pieces or equivalent. See Special Tools.

J 41013 Rotor Resurfacing Kit. See Special Tools.

J 42450-A Wheel Hub Resurfacing Kit. See Special Tools.

J 45101 Hub and Wheel Runout Gage. See Special Tools.

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

Measuring Procedure

1. Matchmark the position of the brake rotor to the wheel studs if this has not been done

already.

CAUTION: Refer to Brake Dust Caution .

IMPORTANT:

Brake rotor assembled lateral runout (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).

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.

IMPORTANT: Whenever the brake rotor has been separated from the

hub/axle flange, any rust or contaminants should be cleaned
from the hub/axle flange and the brake rotor mating surfaces.
Failure to do this may result in excessive assembled lateral
runout (LRO) of the brake rotor, which could lead to brake
pulsation.

2007 Hummer H3

2007 BRAKES Disc Brakes - H3

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

no foreign particles, corrosion, rust or debris remaining. If the wheel hub/axle flange and/or
if the brake rotor mating surfaces exhibit these conditions, perform the following steps:

1. Remove the brake rotor from the vehicle. Refer to Front Brake Rotor Replacement

and/or Rear Brake Rotor Replacement .

2. Using the J 42450-A , thoroughly clean any rust or corrosion from the mating surface

of the hub/axle flange. See Special Tools.

3. Using the J 41013 , thoroughly clean any rust or corrosion from the mating surface of

the brake rotor.

4. Clean the friction surfaces of the brake rotor with denatured alcohol or an equivalent

approved brake cleaner.

3. Install the rotor to the hub/axle flange using the matchmark made prior to removal.

2007 Hummer H3

2007 BRAKES Disc Brakes - H3

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.

2007 Hummer H3

2007 BRAKES Disc Brakes - H3