SPRING U-BOLT CHECKS
Check U-bolt nuts and re-torque every 36000 miles (60000 kilometers)
after initial 1000 mile (1600 kilometer) re-torque. The U-bolt and nut
threads and seats should be cleaned and lubricated to make sure peak
condition when re-torqued.
U-bolt Nut Torque
Suspension ft-lb N•m
Front axle – 8500 lb (3856 kg) 180-200 244-271
Front axle – 10000 lb (4536 kg) and higher 260-300 353-407
Rear axle with multi-leaf 260-300 353-407
Rear axle with IROS air suspension 370-400 502-542
Rear axle with Hendrickson air suspension 400–450 542–610
See air suspension U-bolt re-torquing and installation information below.
Air Suspension U-bolt Checks and Re-torquing Procedures
1. Inspect the threads of the U-bolt and nut for rust and debris. Clean
the threads if contaminated.
2. Using a torque wrench, determine if any nuts can be turned with a
force below the specified torque.
3. Using the lowest discovered torqued nut as a starting point,
re-tighten the nuts using the sequence listed underAir suspension
U-bolt and U-bolt nut installation.
Air Suspension U-bolt and U-bolt Nut Installation
1. Inspect the threads of the U-bolt and nut for rust and debris. Clean
the threads if contaminated.
2. Install the U-bolts and nuts and torque the nuts to seat the cap flat
which is about 18 ft-lb (25 N•m) using a diagonal pattern. Use the
same diagonal pattern for each of the following U-bolt nut re-torque
steps.
3. Tighten U-bolt nuts in increments of 74 ft-lb (100 N•m) until
tightened to final torque for the particular suspension.
228Maintenance
2013 F-650/750(f67)
Owners Guide gf, 2nd Printing, March 2013
USA(fus)
