Peterbilt Model 320 Operator's Manual after 8-07 - Peterbilt Motors ...

Frame Fastener Torque Specifications
regularly. Be sure someone with the proper training and
the right tools checks and tightens the U-bolts on your Peterbilt.
The proper torque requirements are specified in the
Peterbilt Maintenance Manual for your vehicle.
Fasteners
PART 8: MAINTENANCE AND SERVICE
WARNING! U-bolts that are too loose can cause
an injury accident. Loose U-bolts can cause uneven
tire wear, poor alignment, and loss of control
of your vehicle. You probably can’t tighten
U-bolts correctly yourself. But be sure to have
them checked and tightened regularly by an authorized
mechanic.
• For on-highway vehicles, tighten the U-bolts
after the first 15,000 miles (24,000 km). Then
tighten them every 60,000 miles (96,000 km)
after that.
• For off-highway vehicles, tighten the U-bolts
after the first day or two of operation. Then
tighten them every 15,000 miles (24,000 km)
after that.
• Failure to maintain the specified torque
values or to replace worn parts can cause
component system failure, possibly resulting
in an injury accident. Improperly tightened
(loose) suspension U-bolts can lead to
unsafe vehicle conditions, including: hard
steering, axle misalignment, spring breakage
or abnormal tire wear.
Frame Fastener Torque Specifications
Fastener Type
Bolt / Locknut
/ Hardened
Washer
Fastener Size
Lb. ft.
Torque
N.m.
1/2 Inch 86 - 108 117 - 147
5/8 Inch 130 - 163 176 - 221
M12 65 - 85 89 -115
M16 155 -195 210 - 264
M20 315 - 385 427 - 523
CAUTION: When installing bolts on the frame,
use only metric grade 10.9 bolts of the proper
length.
– 178 – Y53-6015 R(08/07)