Rear Axle and Suspension Preventive Maintenance
– 212 – Y53-6008
Medium Duty (R10/06)
REAR AXLE AND SUSPENSION
General Maintenance
WARNING! Do not work on the vehicle without
the parking brake set and wheels chocked
securely. If the vehicle is not secured to prevent
uncontrolled vehicle movement, it could roll and
cause serious personal injury or damage to the
vehicle.
• Use wood blocks (4 in. X 4 in. or larger) against the
front and rear surfaces of the tires. Be sure the vehi-
cle cannot move.
Your vehicle's suspension, by design, requires a minimal
amount of maintenance. However, suspensions in “over-the-
road” operations require periodic inspection to ensure trou-
ble-free performance.
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 suspen-
sion. This could cause loss of vehicle control
and an injury accident. Loose U–bolts can also
cause uneven tire wear and poor alignment.
WARNING! 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 mis-
alignment, spring breakage or abnormal tire
wear. See the Fastener Torque Tables for proper
torque specifications.
CAUTION: Do not spray the suspension with
chemical products or mineral oil; it can cause
damage to the bushings.
NOTE: Failure to follow these recommendations
could void warranty. See the “Medium Duty Mainte-
nance Manual” for further information on servicing
the rear suspension.
Visual Inspection
For all vehicles, mandatory maintenance procedures include
retightening of U–bolts and complete inspection. However,
even with proper maintenance, many factors affect the ser-
vice life of springs and suspension components, such as:
fatigue, vehicle gross weight, type of load, road conditions
and vehicle speed.
