Air Spring/Air Bag

Replace the rear air spring/air bag assembly on a 1994-2007 Dodge Ram 2500 4WD with 5.9L Cummins diesel engine to restore proper ride height and suspension function.

Warnings

Tools required

Parts

• Rear air spring/air bag assembly × 1 — Use OEM specification or quality aftermarket equivalent
• Air line O-rings × 2 — If air line fittings are disturbed

Preparation

1. Park vehicle on level ground and apply parking brake
2. Place wheel chocks in front of front wheels
3. Turn off air suspension compressor or disconnect power to compressor to depressurize system
4. Allow system to depressurize for at least 5 minutes before beginning work
5. Loosen rear wheel lug nuts while vehicle is on ground

Procedure

1. 1

   Raise and support vehicle
   Raise the rear of the vehicle using a floor jack at the rear axle differential. Once raised to working height, place jack stands under the frame rails near the rear axle. Lower the vehicle onto the jack stands while keeping slight upward pressure on the axle with the floor jack. Ensure the suspension is not fully extended to avoid tension on the air spring.
2. 2

   Remove rear wheel
   Remove the lug nuts completely and take off the rear wheel on the side where the air spring is being replaced. Set the wheel aside in a safe location.
   Torque spec

   Wheel Lug Nuts183 Nm (135 lb-ft)
3. 3

   Locate and access air spring
   Identify the air spring assembly mounted between the rear axle and the frame rail. The air spring will be visible inside the rear suspension area. Use a shop light to inspect the mounting points at the top (frame mount) and bottom (axle mount).
4. 4

   Disconnect air line
   Locate the air line connection to the air spring, typically at the top or side of the air bag. Press the release collar on the push-to-connect fitting and pull the air line straight out. If equipped with threaded fittings, use appropriate wrenches to disconnect. Inspect the O-ring on the air line for damage and replace if necessary.
5. 5

   Remove upper mounting hardware
   Access the upper mounting bolts/nuts that secure the air spring to the frame bracket. These are typically accessed from above the frame rail or through an access hole. Remove the mounting hardware completely. Apply penetrating oil if fasteners are corroded or difficult to remove.
6. 6

   Support axle and remove lower mounting hardware
   Use the floor jack to slightly raise or lower the rear axle as needed to relieve tension on the air spring lower mount. Remove the lower mounting bolts/nuts that secure the air spring to the axle bracket. Carefully note the orientation and position of any washers or spacers.
7. 7

   Remove air spring assembly
   With both upper and lower mounts disconnected, carefully remove the air spring from the vehicle. It may be necessary to manipulate the axle position slightly with the floor jack to create clearance. Inspect the mounting brackets on both the frame and axle for damage, cracks, or excessive corrosion.
8. 8

   Clean mounting surfaces
   Use a wire brush to clean both the upper frame mounting surface and lower axle mounting surface. Remove all rust, debris, and old gasket material. Inspect mounting studs or threaded holes for damage. Clean the mounting bracket areas thoroughly to ensure proper seating of the new air spring.
9. 9

   Install new air spring lower mount
   Position the new air spring assembly and align the lower mount with the axle bracket. Use the floor jack to adjust axle height as needed for alignment. Install the lower mounting bolts/nuts and hardware in the correct orientation, but do not fully tighten yet. Ensure any spacers or washers are reinstalled in their original positions.
10. 10

    Install upper mount and torque fasteners
    Align the upper portion of the air spring with the frame bracket. Install the upper mounting bolts/nuts. Once both upper and lower mounts are installed and aligned properly, torque the mounting bolts to specification. Start with the upper mount, then torque the lower mount.
11. 11

    Reconnect air line
    If O-rings were damaged, install new O-rings on the air line fitting. Connect the air line to the air spring fitting by pushing firmly until it clicks into place (push-to-connect type), or thread and tighten the fitting (threaded type). Gently pull on the line to verify it is securely connected.
12. 12

    Reinstall wheel and lower vehicle
    Reinstall the rear wheel onto the hub. Thread all lug nuts on by hand to prevent cross-threading. Snug the lug nuts in a star pattern with a wrench, but do not torque yet. Raise the vehicle slightly with the floor jack, remove the jack stands, and carefully lower the vehicle to the ground.
13. 13

    Torque wheel lug nuts
    With the vehicle on the ground and full weight on the wheels, torque the wheel lug nuts to specification using a star pattern. This ensures even pressure distribution and proper wheel seating.
    Torque spec

    Wheel Lug Nuts183 Nm (135 lb-ft)

Reassembly

1. Ensure all mounting hardware is torqued to specification before pressurizing the system
2. Verify air line connections are secure and properly seated to prevent air leaks
3. Double-check that no tools or parts were left in the suspension area

Verification

• Restore power to the air suspension compressor and allow the system to pressurize
• Listen for air leaks at the new air spring and air line connections. Apply soapy water to fittings to check for bubbles if leak is suspected
• Observe the air spring inflating to proper ride height. Vehicle should sit level side-to-side
• Test drive the vehicle and verify proper ride quality and suspension function
• Recheck all mounting hardware torque after first 50 miles of driving
• Monitor air spring for leaks over the next few days, checking compressor cycle frequency

Related trouble codes on this vehicle

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