This procedure replaces the brake proportioning valve on a 2012-2018 Jeep Wrangler JK with the 3.6L V6 engine, which controls brake pressure distribution between front and rear axles.

Warnings

Tools required

Parts

• Brake proportioning valve assembly × 1 — Mopar 68088970AA or equivalent
• Brake line sealing washers × 4 — Use OEM specification
• Mopar DOT 4 Brake Fluid × 1 — Mopar brake fluid or DOT 4 equivalent

Fluids

• Mopar DOT 4 Brake Fluid — 1 qt

Preparation

1. Park vehicle on level ground and engage parking brake firmly
2. Chock rear wheels securely with wheel chocks on both sides
3. Open hood and locate brake master cylinder reservoir. Check fluid level and top off with fresh DOT 4 brake fluid
4. Raise front of vehicle using floor jack and support securely on jack stands at frame rails
5. Remove driver's side front wheel to improve access to proportioning valve area
6. Locate proportioning valve on driver's side frame rail, approximately 18 inches behind the master cylinder
7. Spray all brake line fittings at the proportioning valve with penetrating oil and allow to soak for 10-15 minutes
8. Place drain pan under proportioning valve area to catch brake fluid
9. Have brake line plugs or caps ready to immediately seal open lines to prevent fluid loss and contamination

Procedure

1. 1

   Label and document brake line connections
   Before disconnecting anything, carefully note or photograph the routing of all four brake lines connected to the proportioning valve. There are typically two inlet lines from the master cylinder and two outlet lines to the front and rear brake circuits. Label each line with tape to ensure correct reconnection.
2. 2

   Disconnect first brake line from proportioning valve
   Using the appropriate flare nut wrench (typically 3/8" or 7/16"), carefully loosen the first brake line fitting at the proportioning valve. Hold the valve body steady with another wrench to prevent twisting the mounting bracket. Once loose, unthread the fitting by hand and immediately plug the open line with a brake line cap to minimize fluid loss.
   ⚠Use only flare nut wrenches on brake line fittings. Regular open-end wrenches will round off the soft brass fittings, making removal impossible and requiring brake line replacement.
3. 3

   Disconnect remaining brake lines
   Repeat the disconnection process for the remaining three brake lines connected to the proportioning valve. Work carefully to avoid cross-threading or damaging fittings. Cap each line immediately after removal. Monitor the master cylinder reservoir level and top off if needed to prevent it from running dry.
4. 4

   Remove proportioning valve mounting bolts
   Locate the mounting bolts securing the proportioning valve bracket to the frame rail (typically two bolts). Use a 13mm socket or wrench to remove these mounting bolts. Support the valve assembly as you remove the last bolt to prevent it from falling. Remove the complete valve assembly from the vehicle.
   Torque spec

   Mounting Bolts31 Nm (23 lb-ft)
5. 5

   Inspect brake line condition
   With the valve removed, carefully inspect all four brake line ends for damage, corrosion, or deformation. Check that the flare seats are clean and undamaged. If any lines show signs of cracking, severe corrosion, or damaged flares, they must be replaced before installing the new valve. Clean the mounting area on the frame rail.
6. 6

   Prepare new proportioning valve
   Remove the new proportioning valve from packaging. Verify that all ports are free of debris and protective caps are removed. Install new sealing washers on each port if provided separately. Compare the new valve to the old unit to confirm correct replacement part before installation.
7. 7

   Mount new proportioning valve to frame
   Position the new proportioning valve assembly in the mounting location on the frame rail, aligning the mounting holes with the frame. Thread in the mounting bolts by hand first to ensure proper alignment. Using a torque wrench, tighten the mounting bolts to 31 Nm (23 lb-ft) in an alternating pattern to seat the bracket evenly against the frame.
   Torque spec

   Mounting Bolts31 Nm (23 lb-ft)
8. 8

   Connect brake lines to new valve
   Remove the caps from the brake lines. Starting with the inlet lines from the master cylinder, thread each brake line fitting into the correct port on the proportioning valve by hand to avoid cross-threading. Ensure each fitting threads in smoothly for at least 3-4 full turns before using a wrench. Using a flare nut wrench and torque wrench, tighten each line fitting to 23 Nm (17 lb-ft). Use a backup wrench on the valve body to prevent the valve from twisting during tightening.
   ⚠Do not over-torque brake line fittings. Excessive torque will strip the threads or crack the flare, causing brake fluid leaks and brake failure.
   Torque spec

   Line Fittings23 Nm (17 lb-ft)
9. 9

   Refill master cylinder reservoir
   Go to the master cylinder reservoir under the hood and fill it to the MAX line with fresh DOT 4 brake fluid from a sealed container. Keep the reservoir filled throughout the bleeding process to prevent air from entering the system.
10. 10

    Bleed brake system - rear brakes first
    Bleed the brake system starting with the wheel furthest from the master cylinder (typically passenger rear, then driver rear). At each wheel, attach clear tubing to the bleeder screw and submerge the other end in a container of clean brake fluid. Have an assistant pump the brake pedal 3-4 times and hold pressure. Open the bleeder screw with a 10mm wrench while pressure is applied, allowing fluid and air to escape. Close the bleeder before the pedal reaches the floor. Repeat until no air bubbles appear in the tubing. Torque each bleeder screw to 16 Nm (12 lb-ft) when complete.
    ⚠️Check master cylinder reservoir level every 3-4 brake pumps. If the reservoir runs dry, air will enter the entire system requiring complete re-bleeding of all wheels.
    Torque spec

    Bleeder Screw16 Nm (12 lb-ft)
11. 11

    Bleed brake system - front brakes
    Continue bleeding process with front brakes (typically passenger front, then driver front). Use the same procedure as rear brakes. Continue bleeding each wheel until brake pedal feels firm and no air bubbles are visible in the discharge tubing. Check all brake line connections at the proportioning valve for any signs of seepage or leaks during bleeding.
    Torque spec

    Bleeder Screw16 Nm (12 lb-ft)
12. 12

    Final fluid level check and leak inspection
    Top off the master cylinder reservoir to the MAX line with fresh DOT 4 brake fluid. Secure the reservoir cap. Carefully inspect all four brake line connections at the proportioning valve for any signs of fluid leakage. Wipe the valve area clean with a shop rag and observe for several minutes while pumping the brake pedal to check for seepage.
    ⚠️Any brake fluid leakage at the proportioning valve indicates improper installation or damaged components. Do not drive the vehicle if any leaks are present. Re-torque fittings or replace damaged lines as needed.

Reassembly

1. Reinstall driver's side front wheel and hand-tighten lug nuts in a star pattern
2. Lower vehicle from jack stands to the ground using floor jack
3. With vehicle weight on the ground, torque wheel lug nuts to 156 Nm (115 lb-ft) in a star pattern using torque wrench
4. Remove wheel chocks and release parking brake
5. Clean any brake fluid spills from frame, suspension components, and wheel with water immediately

Verification

• Start engine and pump brake pedal several times. Pedal should feel firm and hold steady pressure without slowly sinking to the floor
• With engine running, apply firm brake pressure and hold for 60 seconds. Pedal should not slowly sink, indicating no internal leaks
• Inspect proportioning valve area one final time with pedal pressure applied. No fluid should be seeping from any connection
• Perform a careful test drive in a safe, low-traffic area. Begin with slow-speed stops (10-15 mph) to verify basic brake function
• Gradually increase test speeds, verifying that brakes apply evenly without pulling to one side and that the pedal remains firm
• Test vehicle at normal highway speeds in a safe area, ensuring full braking capability is restored
• After test drive, re-inspect all brake line connections at the proportioning valve for any signs of leakage
• Check master cylinder reservoir level one final time and top off if needed. Level should not have dropped significantly if bleeding was done properly
• If brake pedal feels soft, brake performance is degraded, or any leaks are present, DO NOT drive the vehicle. Re-bleed the system or seek professional assistance immediately

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