This procedure replaces the brake booster check valve, which prevents vacuum loss when the engine is off and ensures proper power brake assist operation.

Warnings

Tools required

Parts

• Brake booster check valve with grommet × 1 — Mopar 68028699AA or equivalent

Preparation

1. Park vehicle on level ground and apply parking brake
2. Allow engine to cool if recently operated
3. Open hood and secure with prop rod
4. Locate the brake booster on the driver's side firewall behind the master cylinder
5. Identify the vacuum hose connection on the front of the brake booster - this is where the check valve is installed

Procedure

1. 1

   Access the brake booster check valve
   The check valve is located at the front center of the brake booster where the vacuum hose connects. On the 3.6L V6, you may need to move aside some wiring harnesses or hoses for better access. Use a flashlight to clearly see the connection point. The valve is pressed into a rubber grommet in the booster housing.
2. 2

   Disconnect the vacuum hose
   Grasp the vacuum hose firmly near the connection point to the check valve. Twist the hose gently while pulling straight off the check valve. If the hose is stuck due to age, carefully use a flathead screwdriver to pry between the hose and valve body, working around the circumference. Avoid tearing the vacuum hose.
3. 3

   Remove the old check valve
   Grasp the check valve body firmly with your fingers or needle nose pliers. Pull straight out from the brake booster with steady force. The valve is retained only by the rubber grommet and should pull free. If stuck, twist slightly while pulling. The rubber grommet may come out with the valve or remain in the booster housing.
4. 4

   Inspect and remove the grommet
   If the rubber grommet remained in the brake booster housing, use a pick tool or flathead screwdriver to carefully pry it out. Inspect the grommet for cracks, hardening, or deformation. The new check valve typically includes a new grommet - use the new one even if the old grommet appears serviceable.
5. 5

   Inspect the old check valve
   Examine the removed check valve for damage, debris, or contamination. The valve contains an internal spring and diaphragm. Shake it - you should hear the internal components rattle. Test it by blowing through both ends: air should flow easily from the hose end toward the booster, but not in reverse. This confirms proper directional flow.
6. 6

   Prepare the new check valve
   Remove the new check valve from packaging. Verify it includes a new rubber grommet. Install the rubber grommet onto the check valve body at the end that inserts into the booster. Ensure the grommet is fully seated in its groove on the valve body. Identify the correct orientation: the tapered or smaller end typically points toward the booster, with the larger diameter end accepting the vacuum hose.
7. 7

   Install the new grommet and check valve
   Apply a small amount of clean brake fluid or soapy water to the outside of the grommet to aid installation (do not use petroleum-based lubricants). Align the check valve with the hole in the brake booster housing. Push the valve straight in with firm, steady pressure until the grommet seats completely flush against the booster housing. Ensure the valve is oriented correctly with the vacuum hose connection pointing outward.
8. 8

   Reconnect the vacuum hose
   Push the vacuum hose firmly onto the check valve until it bottoms out and is fully seated. Tug on the hose to verify it is securely connected and will not pull off. The hose should fit snugly with no air gaps visible at the connection.
9. 9

   Verify installation and check for vacuum leaks
   Visually confirm the check valve is fully seated in the booster housing with no gaps. Start the engine and listen carefully for any hissing sounds indicating a vacuum leak at the check valve connection or grommet. The engine should idle smoothly with no vacuum leak noise. Rev the engine slightly and verify stable idle returns.

Reassembly

1. Reposition any wiring harnesses or hoses that were moved during access
2. Close hood and verify it latches securely

Verification

• With engine running, press the brake pedal - it should feel firm with normal power assist and require moderate effort
• Turn off the engine and wait 10 seconds. Press the brake pedal - the first application should still have some power assist from stored vacuum
• Continue pumping the brake pedal with the engine off - you should get 2-3 power-assisted applications before the pedal becomes noticeably harder as vacuum depletes
• If the pedal becomes hard immediately with engine off, the check valve may be installed backwards or defective
• Test drive in a safe area at low speed to verify normal brake operation and adequate stopping power
• After test drive, recheck the check valve connection for any vacuum leaks with engine running

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