U-BOLT NUT TORQUE
U-bolt diameter (nominal) (all
spring suspensions)U-bolt diameter (nominal)
N.m Ft. lbs.
IROS Air w/15,500 lb. axles and
less353–407 260–300
IROS Air w/ greater than 15,500
lb. axles502–542 370–400
Hendrickson 23,000 lb. axle 502–542 370–400
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, retighten
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 20 N.m. (15 ft.
lbs.), using a diagonal pattern.
3. Re-torque the nuts to 136 N.m. (100 ft. lbs.), using a diagonal pattern.
4. Re-torque the nuts to 271 N.m. (200 ft. lbs.), using a diagonal pattern.
5. Re-torque the nuts to 542 (400 ft. lbs.), using a diagonal pattern. (For
vehicles equipped with 14ACC, 14 ADN and 14ADP axles, do not use
Step 6.)
6. Re-torque the nuts to 576 N.m. (425 ft. lbs.), using a diagonal pattern.
(For vehicles equipped with 14ACC, 14 ADN and 14ADP axles.)
7. Use the same diagonal pattern with each U-bolt nut re-torque.
Spring U-bolt checks
Check U-bolt nuts and re-torque every 58,000 km (36,000 miles) after
initial 1,600 km (1,000 mile) re-torque. The U-bolt and nut threads and
seats should be cleaned and lubricated to assure peak condition when
re-torqued.
2004 F650/750(f67)
Supplement
USA English(fus)
Maintenance and specifications
197
