operators_manual

life, replace the complete assembly
if cracks or other defects are
detected.
• After replacement of any part or
discovery of loose components,
check the torque of all fasteners.
• New springs settle-in after the
vehicle's initial service, causing the
U-bolts to become loose.
Rear Suspension Fasteners
To maintain the performance of the air
suspension, check fastener torque values
after the first 2,000 miles (3,218 km) of
service and every 60,000 miles (96,000
km) thereafter. Torque recommendations
apply to fasteners supplied and installed by
vehicle manufacture. The values listed in
the at the back of this chapter
(Specification Reference Charts), are for
cadmium plated or phosphate and oil
fasteners only. U-bolts are difficult to
tighten unless you have the right
equipment. If you cannot tighten them
correctly yourself, be sure to have them
checked and tightened regularly by an
authorized mechanic.
Rear Suspension U-Bolts
NOTE
To ensure an accurate torque reading,
use properly maintained and calibrated
torque wrenches. Clean the nut and
bolt. No dirt, grit, or rust should be
present.
WARNING
Do not operate the vehicle if the sus-
pension U bolts are not properly tight-
ened. Loose U bolts will cause the
axle to not be properly secured to the
suspension, which could cause loss of
vehicle control and an accident. Loose
U bolts can also cause uneven tire
wear and poor alignment. Failure to
comply may result in death, personal
injury, equipment or property damage.
NOTE
Whenever possible, torque all frame
fasteners on the nut end, not the bolt
head.
Load the vehicle to its normal gross weight
before tightening U-bolts. Loading the
vehicle ensures proper adjustment of the
U-bolt and spring assembly.
WARNING
Do not replace U bolts and nuts with
common U bolts or standard nuts.
These parts are critical to vehicle safe-
ty. If the wrong U bolts or nuts are
used, the axle could loosen or sepa-
rate from the vehicle and cause a seri-
ous accident. Use only U bolts and
nuts of SAE Grade 8 specification or
better. Failure to comply may result in
death, personal injury, equipment or
property damage.
Related reference
Rear Axle Lubrication
Lubrication requirements for rear axles.
See the axle manufacturer's operator's
manual for lubrication specifications and
service intervals.
Check oil level with the vehicle parked on
level ground and the fluid warm. The level
MAINTENANCE - Rear Axle and Suspension
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