operators_manual

your vehicle to an authorized dealer
familiar with aligning wheels on your
vehicle.
Suspension U-Bolts
It is important that U-bolts remain tight.
Severe use of your vehicle will cause them
to loosen faster, and all vehicles need to
have their U-bolts checked and tightened
regularly. Be sure someone with the proper
training and the right tools checks and
tightens the U-bolts on your 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. Re-torque
the front spring pinch bolts and shackle
pinch bolts.
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.
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. Tighten U-bolt
nuts to the specified torque value with the
vehicle loaded to its normal gross weight.
See Suspension U-Bolts, Grade 8 on page
306 specifications for torque values
applying to U-bolts and nuts.
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.
PACCAR 20k Front Axle
Lubrication
Proper lubrication practices are important
in maximizing the service life of the steer
axle assembly.
Kingpins, Thrust Bearings, and Tie
Rod Ends
On-Highway Applications -
Standard
• Pressure lubricate every 6 months
or 25,000 miles (40,000 km).
• A more frequent lubrication cycle is
required for axles used in on/off-
highway, refuse, or other severe
service applications. Use heavy-
duty, multipurpose lithium base (#2
grade) grease.
MAINTENANCE - Front Axle and Suspension
Y53-6126-1A1 (01/21) 275
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