For 1990-2009 cars

### Removal Procedure

1. Block the wheels.
2. Drain all of the air reservoirs. Refer to Draining Reservoirs .
3. Tag or label the lines for installation.
4. Remove the air lines from the relay double check valve. Refer to Hose and Line Replacement - Nylon and Metal Compression .
5. Remove the relay double check valve.
6. Inspect the air lines for the following conditions:

• | Damage

• | Kinks

• | Wear

7. Replace any damaged, kinked, or worn air lines.

### Installation Procedure

1. Install the relay double check valve.

Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

2. Install the following components:

• | The bolts

Tighten
Tighten the relay valve bolts to 52 N·m (38 lb ft).

• | The washers

• | The nuts

3. Install the air lines to the relay double check valve. Refer to Hose and Line Replacement - Nylon and Metal Compression .
4. Perform the air leakage test. Refer to Rear Relay Double Check Valve Operational Check .
5. Perform the operational test. Refer to Rear Relay Double Check Valve Leakage Test .
6. Remove the wheel blocks.