GM Astro/Safari 1985-1996 Repair Guide

EHCU Valve/BPMV (4WAL)

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REMOVAL & INSTALLATION



Except 1996 Models

See Figures 1 and 2



Click image to see an enlarged view

Fig. Fig. 1: EHCU/BPMV mounting



Click image to see an enlarged view

Fig. Fig. 2: ECHU/BPMV brake line connections

The EHCU valve is not serviceable. Replace the valve only when defective.

  1. Disconnect the negative battery cable.
  2.  
  3. Disconnect the intermediate steering shaft from the steering column.
  4.  
  5. Disconnect the brake lines from the bottom of the combination valve.
  6.  
  7. Disconnect the electrical connectors from the master cylinder and EHCU.
  8.  
  9. Remove the master cylinder and combination valve.
  10.  
  11. Disconnect the brake lines from the EHCU using a flare nut wrench.
  12.  
  13. Remove the bolts, nuts and EHCU from the vehicle.
  14.  

To install:
  1. Install the EHCU onto the bracket. Torque the mounting bolt to 33 ft. lbs. (45 Nm) and the nuts to 20 ft. lbs. (27 Nm).
  2.  
  3. Connect the electrical connectors and hydraulic lines. Torque the line fittings to 16 ft. lbs. (25 Nm).
  4.  
  5. Install the master cylinder, combination valve and hydraulic lines.
  6.  
  7. Reconnect the intermediate steering shaft.
  8.  
  9. Bleed the system and the EHCU.
  10.  
  11. Connect the negative battery cable, pump the brakes before road test and road test
  12.  

1996 Models

See Figures 3 and 4



Click image to see an enlarged view

Fig. Fig. 3: EHCU/BPMV mounting-1996 models



Click image to see an enlarged view

Fig. Fig. 4: EHCU/BPMV exploded view-1996 models

  1. Disconnect the negative battery cable.
  2.  
  3. Raise and safely support the vehicle.
  4.  
  5. Remove the two 13mm bolts that hold the unit to the bracket.
  6.  
  7. Unplug the electrical connectors from the unit.
  8.  
  9. Using a flare wrench, disconnect the hydraulic lines from the unit.
  10.  
  11. Remove the unit from the vehicle.
  12.  

To install:
  1. Install the unit in the vehicle and connect the hydraulic lines. Torque the fittings to 18 ft. lbs. (24 Nm).
  2.  
  3. Install the two 13mm mounting bolts and torque to 84 inch lbs. (9 Nm).
  4.  
  5. Plug in the electrical connectors.
  6.  
  7. Connect the negative battery cable.
  8.  
  9. Bleed the hydraulic system.
  10.  
  11. Lower the vehicle.
  12.  

 
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