Remove and replace the ABS hydraulic control unit (HCU/pump) assembly, including brake line disconnection, mounting hardware removal, and complete system bleeding.

Warnings

Tools required

Parts

• ABS Hydraulic Control Unit (HCU/Pump) × 1 — Use OEM Mopar part
• Brake line sealing washers × 6 — Copper or aluminum crush washers for brake fittings
• ABS pump mounting gasket or seal (if equipped) × 1 — Verify if used on your specific model

Fluids

• Mopar DOT 4 Brake Fluid — 2 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Disconnect negative battery cable and wait 5 minutes to deplete airbag system capacitors
3. Remove engine cover if it restricts access to master cylinder area
4. Place drain pan under work area to catch brake fluid spillage
5. Clean area around master cylinder and ABS unit with brake cleaner to prevent contamination
6. Have all brake line caps ready to immediately seal lines upon disconnection

Procedure

1. 1

   Access the ABS pump assembly
   The ABS hydraulic control unit is located on the driver's side frame rail, below the master cylinder area. Remove any plastic covers or shields obstructing access. On 4WD models, you may need to work around the transfer case. Identify all six brake line connections to the HCU (four wheel lines and two lines from master cylinder).
2. 2

   Label and disconnect brake lines
   Clearly label each brake line with its position (LF, RF, LR, RR, Master In, Master Out). Using the appropriate flare nut wrench, carefully loosen each brake line fitting at the HCU. Work slowly to avoid rounding off the fittings. Once loosened, finish removal by hand and immediately cap both the line and the HCU port to prevent fluid loss and contamination. Be prepared for significant fluid spillage.
   ⚠Use only flare nut wrenches on brake line fittings. Standard open-end wrenches will round off the soft brass fittings.
3. 3

   Disconnect ABS electrical connectors
   Locate the two electrical connectors on the ABS pump: the large pump motor connector and the smaller electronic control module connector. Press the locking tabs and carefully disconnect both connectors. Move them aside to prevent damage during pump removal.
4. 4

   Remove ABS pump mounting hardware
   The ABS unit is secured by mounting bolts to a bracket on the frame rail. Remove the mounting bolts securing the HCU to its bracket. Support the unit weight as you remove the final bolt.
   Torque spec

   Mounting Bolts37 Nm (27 lb-ft)
5. 5

   Remove ABS pump assembly
   Carefully lower and remove the ABS hydraulic control unit from the vehicle. Note the orientation and any alignment pins or guides. Place the old unit on a clean work surface and verify all lines and connectors are disconnected. Inspect the mounting bracket for damage or corrosion.
6. 6

   Prepare new ABS pump for installation
   Unpack the new ABS unit and verify it matches the original. Some replacement units come pre-filled with brake fluid while others are dry. Check all ports for shipping caps. Replace all brake line sealing washers with new copper or aluminum crush washers. Clean mounting surfaces on bracket with wire brush if needed.
7. 7

   Install new ABS pump assembly
   Position the new ABS unit onto the mounting bracket, ensuring proper alignment with any guide pins. Thread all mounting bolts by hand first to ensure proper thread engagement, then torque to specification in a cross pattern.
   Torque spec

   Mounting Bolts37 Nm (27 lb-ft)
8. 8

   Reconnect electrical connectors
   Connect both ABS electrical connectors (pump motor and control module) ensuring they click into place securely. Verify locking tabs are fully engaged. Route wiring to avoid any sharp edges or heat sources.
9. 9

   Reconnect brake lines
   Remove caps from brake lines and HCU ports. Install new sealing washers on each brake line fitting. Thread each brake line fitting into its labeled port by hand first to prevent cross-threading. Once all fittings are hand-tight, use the flare nut wrench to carefully tighten each line. Tighten firmly but do not over-torque (typically 12-15 ft-lbs for brake line fittings, though not specified in torque list). Work systematically to ensure no lines are crossed.
   ⚠Cross-threading brake line fittings will ruin the new ABS pump. Always start fittings by hand and ensure they thread smoothly.
10. 10

    Fill master cylinder reservoir
    Fill the brake fluid reservoir with fresh Mopar DOT 4 brake fluid to the MAX line. Keep the reservoir topped off throughout the bleeding process to prevent air from entering the system. Never reuse old brake fluid.
11. 11

    Perform initial manual brake bleeding
    Begin with the wheel furthest from the master cylinder (typically right rear) and work toward the closest (left front). At each wheel, attach a clear hose to the bleeder screw and submerge the other end in a container of clean brake fluid. Have an assistant slowly depress the brake pedal while you open the bleeder screw. Close the bleeder before the pedal reaches the floor. Repeat until fluid flows clear without bubbles. Torque each bleeder screw after bleeding.
    ⚠Never allow the brake pedal to return to the top position while a bleeder screw is open, as this can draw air into the system.
    Torque spec

    Bleeder Screw10 Nm (7 lb-ft)
12. 12

    Perform scan tool ABS bleeding procedure
    Reconnect the battery negative cable. Connect the scan tool to the OBD-II port. Navigate to the ABS system and select the automated bleeding function. The scan tool will cycle the ABS pump and valves to purge air from internal passages that cannot be reached by manual bleeding. Follow the scan tool prompts, which typically involve multiple cycles with brake pedal application. Keep master cylinder reservoir full throughout this process.
    ℹ️This step is CRITICAL. Manual bleeding alone cannot remove air trapped in the ABS hydraulic control unit. Scan tool bleeding is mandatory.
13. 13

    Verify brake system operation
    With engine running, pump brake pedal several times and verify it becomes firm. Pedal should not sink slowly to the floor. Check for leaks at all brake line connections at the ABS unit. Start the engine and verify the ABS warning light extinguishes after a few seconds. Use the scan tool to check for any ABS fault codes. If pedal feel is soft or codes are present, repeat bleeding procedure.

Reassembly

1. Reinstall any engine covers or shields removed during access
2. Double-check all brake line connections for tightness and leaks
3. Verify master cylinder reservoir is at proper level
4. Ensure all electrical connections to ABS pump are secure
5. Clear any brake fluid spills with water before they damage paint

Verification

• With engine running, brake pedal should be firm and hold steady when depressed
• ABS warning light should illuminate with key on, then extinguish within 2-3 seconds after engine start
• Perform test drive in safe area at low speed (under 15 mph) and verify normal brake operation
• Perform controlled ABS activation test in safe area by braking firmly on loose gravel or wet surface to verify ABS pump cycles properly
• Use scan tool to verify no ABS fault codes are present
• Recheck all brake line connections for leaks after test drive
• Verify brake fluid level has not dropped, indicating a leak

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