GM Caprice 1990-1993 Repair Guide

Modulator Valve

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REMOVAL & INSTALLATION



See Figures 1, 2 and 3



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Fig. Fig. 1: ABS modulator assembly located in the engine compartment near the alternator



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Fig. Fig. 2: ABS modulator assembly removal



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Fig. Fig. 3: ABS modulator cover removed to access the solenoid and motor relays and electrical connector


CAUTION
The modulator is not repairable and no screws on the modulator may be loosened. If the screws are loosened, it will not be possible to get the brake circuits leak-proof and personal injury may result.

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the air intake duct and resonator and move the upper coolant hose aside.
  4.  
  5. Disconnect the canister purge line at the canister and move aside.
  6.  
  7. Remove the retaining screw and remove the modulator valve cover.
  8.  
  9. Unlock the tab and disconnect the modulator valve electrical connector.
  10.  
  11. Remove the nut and disconnect the ground wire from the modulator.
  12.  
  13. Note the hydraulic brake pipe locations then disconnect and plug the lines from the modulator to prevent fluid contamination or loss.
  14.  
  15. Remove the 3 nuts retaining the modulator to the bracket.
  16.  
  17. Remove bracket taking care to protect the vehicle from any brake fluid spillage. If replacing the modulator assembly, remove the insulators from the modulator valve.
  18.  

To install:
  1. If applicable, install the insulators to the modulator valve.
  2.  
  3. Install the modulator valve to the bracket and tighten the 3 nuts to 89 inch lbs. (10 Nm).
  4.  
  5. If a new modulator is being used, remove shipping plugs from the valve openings.
  6.  
  7. Connect the hydraulic brake pipes to their original locations in the modulator and tighten to 11 ft. lbs. (15 Nm).
  8.  


CAUTION
If brake pipes are switched (inlet vs. outlet) wheel lockup will occur and personal injury may result.

  1. Install the ground wire and nut to the modulator, tighten nut to 25 inch lbs. (2.8 Nm).
  2.  
  3. Install the modulator valve electrical connector.
  4.  
  5. Install the modulator valve cover with the retaining screw and tighten to 13 inch lbs. (1.5 Nm).
  6.  
  7. Connect the canister purge line to the canister.
  8.  
  9. Install the air intake duct and resonator and move the upper coolant hose into position.
  10.  
  11. Connect the negative battery cable.
  12.  
  13. Use only DOT 3 hydraulic brake fluid, fill and bleed the brake system.
  14.  
  15. Road test the vehicle.
  16.  

 
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