Preventive Maintenance
24
17730-299
ULTIMAAX
®
for Fire and Rescue Vehicles
TORQUE RODS
THE ULTIMAAX SUSPENSION INCORPORATES TORQUE RODS FOR VEHICLE STABILITY . IF THESE
COMPONENTS ARE DISCONNECTED OR ARE NON-FUNCTIONAL THE VEHICLE SHOULD NOT BE
OPERATED . FAILURE TO DO SO CAN RESULT IN ADVERSE VEHICLE HANDLING AND POSSIBLE TIRE
CONTACT WITH THE FRAME OR THE SUSPENSION .
Visually inspect torque rod bushings
for any torn or shredded rubber, inspect for bent, cracked,
or broken torque rods, and for end hubs with any elongated “oval” shape . Any of these conditions
will require component replacement .
Torque rod looseness
inspection is necessary per the following method below .
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With the vehicle shut down, a lever check can be made with a long pry bar placed under each
rod end and pressure applied .
TORQUE ROD LENGTH
Longitudinal torque rod
length is determined by the vehicle manufacturer for optimum drive-
line angles . The longitudinal torque rods maintain these angles and control acceleration and
brake forces .
Transverse torque rod
length is also determined by the vehicle manufacturer to center the axles
under the frame .
■
If the lateral alignment of the axles is incorrect, it may be necessary to shim the transverse
torque rod at the straddle mount end . Shims can be installed between the transverse torque
rod and the transverse torque rod frame bracket or between the transverse torque rod and
axle tower bracket . Refer to vehicle manufacturer for proper shim location; also see Lateral
Alignment in the Alignment & Adjustments Section of this publication .
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The transverse torque rods also control axle walk-out during cornering . The mounting brackets
at the axle housing end of the torque rods are furnished and welded into position on the axle
housings by the axle or vehicle manufacturer .
FIGURE 6-26
Transverse and longitudinal torque
rods
have attaching ends desig-
nated as “straddle mount,” or “tapered
stud” as shown in Figure 6-26 . Most
can be replaced by pressing out the
worn torque rod bushing and install-
ing a replacement bushing, others
require complete torque rod assembly
replacement .
It is important that the tightening
torque of the nuts be checked during preventive maintenance service . Follow the vehicle manu-
facturer’s specifications for tightening torque values .
The tapered stud torque rod locknuts also should be checked . Refer to the Torque Specification
Section of this publication for proper torque values .
Length
Tapered Stud
Straddle Mount