Express, Savana, G1500, G2500, G3500, 1998-2005

Hydro-Boost

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Diesel engine trucks and some 30/3500 series trucks and motor home chassis are equipped with the Bendix Hydro-boost system. This power brake booster obtains hydraulic pressure from the power steering pump, rather than vacuum pressure from the intake manifold as in most gasoline engine brake booster systems.

The system should be bled whenever the booster is removed and installed.

  1. Fill the power steering pump until the fluid level is at the base of the pump reservoir neck. Disconnect the battery lead from the distributor.
    NOTE
    Remove the electrical lead to the fuel solenoid terminal on the injection pump before cranking the engine.

  2.  
  3. Jack up the front of the car, turn the wheels all the way to the left, and crank the engine for a few seconds.
  4.  
  5. Check steering pump fluid level. If necessary, add fluid to the -ADD'' mark on the dipstick.
  6.  
  7. Lower the car, connect the battery lead, and start the engine. Check fluid level and add fluid to the -ADD'' mark, as necessary. With the engine running, turn the wheels from side to side to bleed air from the system. Make sure that the fluid level stays above the internal pump casting.
  8.  
  9. The Hydro-Boost system should now be fully bled. If the fluid is foaming after bleeding, stop the engine, let the system set for one hour, then repeat the second part of Step 4.
  10.  

The preceding procedures should be effective in removing the excess air from the system, however sometimes air may still remain trapped. When this happens the booster may make a gulping noise when the brake is applied. Lightly pumping the brake pedal with the engine running should cause this noise to disappear. After the noise stops, check the pump fluid level and add as necessary.

The system should be bled whenever the booster is removed and installed.

  1. Fill the power steering pump until the fluid level is at the base of the pump reservoir neck. Disconnect the battery lead from the distributor.
    NOTE
    Remove the electrical lead to the fuel solenoid terminal on the injection pump before cranking the engine.

  2.  
  3. Jack up the front of the car, turn the wheels all the way to the left, and crank the engine for a few seconds.
  4.  
  5. Check steering pump fluid level. If necessary, add fluid to the -ADD'' mark on the dipstick.
  6.  
  7. Lower the car, connect the battery lead, and start the engine. Check fluid level and add fluid to the -ADD'' mark, as necessary. With the engine running, turn the wheels from side to side to bleed air from the system. Make sure that the fluid level stays above the internal pump casting.
  8.  
  9. The Hydro-Boost system should now be fully bled. If the fluid is foaming after bleeding, stop the engine, let the system set for one hour, then repeat the second part of Step 4.
  10.  

The preceding procedures should be effective in removing the excess air from the system, however sometimes air may still remain trapped. When this happens the booster may make a gulping noise when the brake is applied. Lightly pumping the brake pedal with the engine running should cause this noise to disappear. After the noise stops, check the pump fluid level and add as necessary.

 
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