Mitsubishi Car 1999-05

Hydraulic Control Unit (HCU)

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Removal & Installation



  1. Disconnect the negative battery cable. Use a syringe or similar device to remove as much fluid as possible from the reservoir. Some fluid will be spilled from lines during removal of the hydraulic unit so make sure to protect adjacent painted surfaces.
  2.  
  3. Remove the left side splash shield.
  4.  
  5. Remove the left side headlight assembly.
  6.  
  7. For the 2.0L non-turbo engine, remove the following components:
    1. Air cleaner assembly
    2.  
    3. Engine Control Module (ECM)
    4.  
    5. Relay box bracket
    6.  

  8.  
  9. For 2.0L turbo and 2.4L engines, unfasten the power steering fluid reservoir mounting bolts. Remove the power steering pressure pipe and return pipe clamp mounting bolts.

    Click image to see an enlarged view

    Fig. ABS hydraulic unit mounting-1999 Eclipse

  10.  
  11. Disconnect the brake lines from the hydraulic unit.
  12.  
  13. Detach the electrical harness connector.
  14.  
  15. Unfasten the bolts, then remove the hydraulic unit assembly.
    WARNING
    Be careful when removing the hydraulic unit, as it is heavier than is looks. Do not disassemble, drop or turn the unit upside down.

  16.  
  17. If necessary, you can remove the retainers then separate the hydraulic unit from the bracket.
  18.  
  19. Installation is the reverse of the removal, but make sure to connect the brake lines to the unit as shown in the accompanying figure.

    Click image to see an enlarged view

    Fig. Hydraulic unit brake line connection identification

  20.  
  21. Properly bleed the brake system, as outlined in this section.
  22.  

  1. Disconnect the negative battery cable. Use a syringe or similar device to remove as much fluid as possible from the reservoir. Some fluid will be spilled from lines during removal of the hydraulic unit so make sure to protect adjacent painted surfaces.
  2.  
  3. Raise and safely support the vehicle.
  4.  
  5. Remove the right side front wheel.
  6.  
  7. Remove the strut tower bar, if equipped.
  8.  
  9. Matchmark and disconnect the brake lines from the hydraulic unit.
  10.  
  11. Remove the electrical harness connector from the unit.
  12.  
  13. Unbolt the bracket that holds the hydraulic unit and remove.
  14.  

To install:

  1. Install the hydraulic unit and tighten the bracket bolts to 22 ft. lbs. (30 Nm).
  2.  
  3. The remainder of the installation is the reverse order of removal.
  4.  
  5. Ensure that the brake lines are installed in their original position.
  6.  
  7. Properly fill and bleed the brake system.
  8.  



Click image to see an enlarged view

Fig. HCU mounting-Mirage



Click image to see an enlarged view

Fig. HCU mounting-Galant

  1. Use a syringe or similar device to remove as much fluid as possible from the reservoir. Some fluid will be spilled from lines during removal of the hydraulic unit; protect adjacent painted surfaces.
    CAUTION
    Brake fluid contains polyglycol ethers and polyglycols. Avoid contact with the eyes and wash your hands thoroughly after handling brake fluid. If you do get brake fluid in your eyes, flush your eyes with clean, running water for 15 minutes. If eye irritation persists, or if you have taken brake fluid internally, IMMEDIATELY seek medical assistance.

  2.  
  3. Remove the splash shield from the left front wheel house or fender area.
  4.  
  5. Remove the coolant reserve tank.
  6.  
  7. Remove the coolant reservoir bracket.
  8.  
  9. Remove the dust shield from below the hydraulic unit.
  10.  
  11. Disconnect the brake hoses and lines from the hydraulic unit. Correct reassembly is critical. Label or identify the lines before removal. Plug each line and each port immediately after removal.
  12.  
  13. Remove the cover from the relay box. Disconnect the electrical harness to the hydraulic unit.
  14.  
  15. Remove the bolts holding the 3 mounting brackets to the vehicle; remove the unit downward and out of the vehicle.
    NOTE
    The hydraulic unit is heavy; use care when removing it. The unit must remain in the upright position at all times and be protected from impact and shock.

  16.  
  17. Set the unit upright, supported by blocks on the workbench. The hydraulic unit must not be tilted or turned upside down. No component of the hydraulic unit should be loosened or disassembled.
  18.  
  19. The brackets and relays may be removed if desired.
  20.  

To install:

  1. Install the brackets and relays if they were removed. Tighten the bracket bolts to 16 ft. lbs. (22 Nm).
  2.  
  3. Install the hydraulic unit into the vehicle, keeping it upright at all times.
  4.  
  5. Install the retaining bolts holding the brackets to the vehicle. Tighten the bolts to 16 ft. lbs. (22 Nm).
  6.  
  7. Connect the hydraulic unit wiring harness.
  8.  
  9. Install the cover on the relay box.
  10.  
  11. Connect each brake line loosely to the correct port and double check the placement. Tighten each line to 10 ft. lbs. (13 Nm).
  12.  
  13. Fill the reservoir to the MAX line with brake fluid.
  14.  
  15. Bleed the brake system.
  16.  
  17. Install the dust shield and the coolant reserve tank with its bracket.
  18.  
  19. Install the fender splash shield.
  20.  
  21. Check ABS system function by turning the ignition ON and observing the dashboard warning lamp. Test drive the vehicle and confirm system operation.
  22.  

The Hydraulic Control Unit (HCU) is located in the engine compartment. It contains the solenoid valves and the pump/motor assembly which provides pressurized fluid for the anti-lock system when necessary. Hydraulic units are not interchangeable on any vehicles. Neither unit is serviceable; if any fault occurs within the hydraulic unit, the entire unit must be replaced.

 
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