Hummer H3. Manual — part 1323

5. If the brake fluid level is above the half-full point, adding brake fluid is not recommended

under normal conditions.

6. If brake fluid is to be added to the master cylinder reservoir, clean the outside of the

reservoir on and around the reservoir cap prior to removing the cap and diaphragm. Use
only Delco Supreme 11®, GM P/N 12377967 (Canadian P/N 992667) or equivalent DOT-
3 brake fluid from a clean, sealed brake fluid container.

MASTER CYLINDER RESERVOIR FILLING (WITH RPO BRM)

1. Visually inspect the brake fluid level through the brake master cylinder reservoir.

2. If the brake fluid level is at or below the half-full point during routine fluid checks, the

brake system should be inspected for wear and possible brake fluid leaks.

3. If the brake fluid level is at or below the half-full point during routine fluid checks and an

CAUTION: Refer to Brake Fluid Irritant Caution in the Preface section.

CAUTION: DOT 4 BRAKE FLUID CAUTION in the Preface section.

NOTE:

When adding fluid to the brake fluid reservoir or to the clutch fluid
reservoir, use only GM Vehicle Care Brake and Clutch Fluid Super
DOT-4, GM P/N 88958860 (Canadian P/N 88901244) or equivalent
DOT-4 brake fluid from a clean, sealed container. This polyglycol
brake fluid is hygroscopic and absorbs moisture. Do not use fluid
from an open container that may be contaminated with water.
Improper or contaminated fluid could result in damage to the
system components.

NOTE:

Refer to Brake Fluid Effects on Paint and Electrical Components
Notice .

IMPORTANT: Before checking the HB-Ci Master Cylinder Reservoir brake fluid

level, the accumulator fluid reserve must be drained. With the
ignition OFF, wait 15 seconds then depress and release the brake
pedal 20 times to deplete accumulator reserve. Failure to drain
the accumulator prior to checking the brake fluid level can lead to
system over filling.

2007 Hummer H3

2007 BRAKES Hydraulic Brakes - H3

inspection of the brake system did not reveal wear or brake fluid leaks, the brake fluid may
be filled to the maximum-fill level.

4. If brake system service was just completed, the brake fluid may be filled to the maximum-

fill level.

5. If the brake fluid level is above the half-full point, adding brake fluid is not recommended

under normal conditions.

6. If brake fluid is to be added to the master cylinder reservoir, clean the outside of the

reservoir on and around the reservoir cap prior to removing the cap and diaphragm. Use
only brake and clutch fluid Super DOT-4, GM P/N 88958860 (Canadian P/N 88901244) or
equivalent DOT-4 brake fluid from a clean, sealed brake fluid container.

MASTER CYLINDER RESERVOIR REPLACEMENT

Special Tools

CH-47830 Holding Fixture

Removal Procedure

1. Using a suitable tool, remove the brake fluid from the master cylinder reservoir.

Discard the brake fluid into an approved container.

2. Remove the brake master cylinder and power brake booster assembly. Refer to Brake

Master Cylinder with Power Brake Booster and Chassis Control Module
Replacement (LHD) or Brake Master Cylinder with Power Brake Booster and
Chassis Control Module Replacement (RHD) .

3. Install the CH-47830 to the master cylinder assembly.

4. Position the CH-47830 with the master cylinder assembly in a vise.

CAUTION: Refer to Brake Fluid Irritant Caution .

2007 Hummer H3

2007 BRAKES Hydraulic Brakes - H3

Fig. 11: View Of Master Cylinder Reservoir & attachments
Courtesy of GENERAL MOTORS CORP.

5. Release the fluid level sensor electrical connector (6) from the bracket.

6. Remove the master cylinder reservoir bolt (1).

7. Remove the master cylinder reservoir roll pin (2).

8. Remove the master cylinder reservoir (3).

2007 Hummer H3

2007 BRAKES Hydraulic Brakes - H3

9. Remove the grommets (4) and (5), if necessary.

Installation Procedure

IMPORTANT:

The grommets for the brake master cylinder should
remain in the brake master cylinder body.

There are 2 different size grommets. The 2 outer
grommets are larger than the center grommet.

2007 Hummer H3

2007 BRAKES Hydraulic Brakes - H3