The following procedure is required when servicing a vehicle with a Hendrickson Suspension model HAS air suspension:

Notice: If the tightening torques recommended are not achieved and maintained, metal surfaces can work and wear the spring seats, axle bottom caps and possibly other components related in the total assembly.

Important: Check for proper seating of components to eliminate gaps or misalignment.

1. Torque the U-bolt nuts at preparation for delivery.
2. Retorque the U-bolt locknuts at regular maintenance intervals. Refer to Maintenance Schedule .




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.

3. Use the following procedure in order to replace the U-bolts or other components:

3.1.	Torque the U-bolt nuts evenly.

Tighten
Use 37 N·m (50 lb ft) increments in order to achieve uniform bolt tension and correct level/altitude of the main support beam, the spring seat, and the axle bottom cap at the final torque.

3.2.	Drive the vehicle in order to seat the components.

3.3.	After the road test, retorque the U-bolt nuts.

Tighten
Tighten the nuts to 394 N·m (291 lb ft).

3.4.	Retorque the U-bolt nuts at regular maintenance intervals. Refer to Maintenance Schedule .