Thursday, July 14, 2011

How to remove HCU on dodge caravan 3.8.?


1996 Vehicles

See Figure 1

Click image to see an enlarged view

Fig. Fig. 1: The HCU is located on the front suspension crossmember

The Hydraulic Control Unit (HCU) is located on the driver's side of the vehicle, mounted onto the front suspension crossmember.

  1. Disconnect and isolate the negative battery cable.
  2. Disengage the HCU 10-way and 2-way connectors from the retaining bracket. Then disengage the HCU 10-way and 2-way connectors from the vehicle wiring harness located on the driver's side strut tower.
  3. Disconnect the HCU wiring pigtail retaining straps from the master cylinder brake tubes. There are 2 retaining straps, one above and one below, the steel braid on the master cylinder tubes.
  4. Using a brake pedal positioning tool, or equivalent, depress the brake pedal past the first 1 inch of travel and hold in this position. This will isolate the master cylinder reservoir from the brake hydraulic system, which will prevent the brake fluid from draining out of the reservoir.
  5. Raise and safely support the vehicle securely on jackstands.
  6. Using Brake Parts Cleaner, thoroughly clean all surfaces, brake line fittings and connections to the HCU.
  7. Label and disconnect the chassis brake tubes from the inlet and outlet ports of the HCU.
  8. Remove the 3 bolts attaching the HCU mounting bracket to the front suspension crossmember.
  9. Remove the HCU and the mounting bracket as a unit from the vehicle, pulling the HCU wiring pigtail through the opened master cylinder tube clip retaining straps.

To install:
  1. Locate and lock the HCU wiring pigtail into the routing clips located on the primary and secondary master cylinder-to-HCU brake tubes. When the wiring pigtail is installed in the routing clips, be sure that the brake tubes and wiring harness do not touch any other components.
  2. Place the HCU and mounting bracket assembly into position on the front suspension crossmember and tighten the mounting bolts to 21 ft. lbs. (28 Nm).
  3. Install the chassis brake tubes into their correct port locations on the HCU valve block. Tighten the brake tube fittings to 13 ft. lbs. (17 Nm).
  4. Lower the vehicle.
  5. Engage the HCU 10-way and 2-way connectors into the vehicle wiring harness connectors.
  6. Install the HCU 10-way and 2-way connectors back into the bracket located on the driver's side strut tower.
  7. Connect the negative battery cable.
  8. Remove the brake pedal positioning tool from the vehicle.
  9. Bleed the base brake system and the ABS hydraulic system.
  10. Road test the vehicle to ensure proper operation of the base and ABS systems.