Ford F-650 2006 Manual page 206

Maintenance and Specifications
FRAME AND TOW HOOKS
Your vehicles chassis is manufactured with frame rails of either HSLA
steel or heat-treated steel. Each must be handled in a specific manner to
ensure maximum service life. Before attempting frame repair or
modification, consult the service manual or your dealer.
It is important, particularly on vehicles where the tow hooks are used
frequently to inspect the front and rear tow hooks for damage or a loose
mounting.
U-BOLT NUT TORQUE
U-bolt diameter (nominal) (all
spring suspensions)
IROS Air w/15,500 lb. axles and
less
IROS Air w/greater than 15,500 lb.
axles
Hendrickson 23,000 lb. axle
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 under Air 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 15 ft. lb. (20 N•m),
using a diagonal pattern.
3. Re-torque the nuts to 100 ft. lb. (136 N•m), using a diagonal pattern.
4. Re-torque the nuts to 200 ft. lb. (271 N•m), using a diagonal pattern.
5. Re-torque the nuts to 400 ft. lb. (542 N•m), using a diagonal pattern.
(For vehicles equipped with 14ACC, 14 ADN and 14ADP axles, do not
use Step 6.)
206
2006 F-650/750 (f67)
Supplement
USA (fus)
U-bolt diameter (nominal)
Ft. lb. N•m
260–300 353–407
370–400 502–542
370–400 502–542