Regional Haul Model Operator's Manual - Peterbilt Motors Company

FRONT AXLE AND SUSPENSION
Torque
CAUTION: Do not spray the suspension with
chemical products or mineral oil; it can cause
damage to the bushings.
U–Bolts, Spring and Shackle Pinch Bolts
It is important that U–bolts remain tight. Severe use of
your vehicle will cause them to loosen faster. But all vehicles
need to have their U–bolts checked and tightened
regularly. See “Maintenance Schedule” on page 152. Be
sure someone with the proper training and the right tools
checks and tightens the U–bolts on your Regional Haul
vehicle.
New springs can “settle in” after service, relieving the tension
on the U–bolts. Loose U–bolts can cause leaf spring
breakage, axle misalignment, hard steering and abnormal
tire wear.
All vehicles should have suspension U–bolts tightened
after the first 500 miles (800 km) of operation. Torque the
front suspension U-bolts to 245-300 lb. ft. (333-408 N.m.)
PREVENTIVE MAINTENANCE
WARNING! Do not operate the vehicle if the
U–bolts are not properly tightened. Loose U–
bolts do not properly secure the axle to the
suspension. This could cause loss of vehicle
control and an accident resulting in death or
injury. Loose U–bolts can also cause uneven
tire wear and poor alignment.
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.
WARNING! Do not replace U–bolts and nuts
with common U–bolts or standard nuts. Use
only U–bolts and nuts of SAE Grade 8 specification
or better.These parts are critical to
vehicle safety. If the wrong U–bolts or nuts
are used, the axle could loosen or separate
from the vehicle and cause an accident resulting
in death or injury.
At the same time U-bolts are tightened, re-torque the
spring and shackle pinch bolts to 105 lb. ft. (142 N. m.)
– 244 – Y53-6033 Regional Haul (R05/10)