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Home >> Hummer >> 2008 >> H2 4D Utility Wagon >> Repair and Diagnosis >> External Pages >> Different car >> Section 209 (Anti-Lock Brake System - Hybrid) >> Repair Instructions >> Brake Pipe Manifold Replacement >> Removal Procedure

Removal Procedure

WARNING: This page is about a different car, the 2008 GMC Yukon and 2008 Chevrolet Tahoe. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION: The high pressure accumulator (HPA) and the chambers of the brake modulator assembly to which it attaches, store brake fluid at extremely high pressures. Fluid pressure must be relieved before attempting to service the HPA. Ensure that the recommended procedures are followed to relieve system pressure, including using the manual pressure release steps. Failure to properly follow procedures to depressurize the system may result in personal injury. 
CAUTION: Refer to Brake Fluid Irritant Caution .
    IMPORTANT: The ignition must be in the OFF position, without pausing at ACCESSORY, and without applying the brake pedal to ensure the brake modulator and high pressure accumulator (HPA) pressure relief occurs. This process will take approximately 1 to 3 minutes.
  1. Turn the ignition to OFF, without pausing at ACCESSORY, and remove the ignition key.
  2. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .
  3. Fig 1: View Of Brake Modulator Manual Pressure Relief Valve
    GM2037952Courtesy of GENERAL MOTORS CORP.
  4. Clean any dirt and debris from the brake modulator assembly and the brake pipe manifold.
  5. IMPORTANT: To ensure brake modulator and HPA pressure relief has occurred, the manual pressure relief valve must be opened momentarily.
  6. Loosen the brake modulator manual pressure relief valve (1) 1/4 turn counterclockwise.
  7. Seat, but do not tighten, the manual pressure relief valve.
  8. Remove the brake pressure modulator valve assembly. Refer to Brake Pressure Modulator Valve Replacement .
  9. Fig 2: View Of Master Cylinder Return & Supply Hoses & O-ring Seals
    GM2037956Courtesy of GENERAL MOTORS CORP.
  10. Remove the master cylinder return hose fitting (1).
  11. Remove the master cylinder supply hose fitting (2).
  12. Remove and discard the O-ring seals (3).
  13. Fig 3: View Of Brake Pipe Manifold Bolts
    GM2037957Courtesy of GENERAL MOTORS CORP.
  14. Remove the brake pipe manifold bolts (1).
  15. Fig 4: View Of Brake Pipe Manifold
    GM2037959Courtesy of GENERAL MOTORS CORP.
  16. Remove the brake pipe manifold (1).
  17. Fig 5: View Of Transfer Tubes & O-ring Seals
    GM2037968Courtesy of GENERAL MOTORS CORP.
  18. Remove the 5 transfer tubes (1).
  19. Remove and discard the 5 upper transfer tube O-ring seals (2).
  20. Remove discard the 5 lower transfer tube O-rings seals (3).