PRIMAAX
®
EX / PRIMAAX
®
for Volvo Vehicles
17730-254
21
Preventive Maintenance
Longitudinal torque rod length
is determined by the truck manufacturer for optimum driveline
angles. The longitudinal torque rods along with the bottom caps maintain these angles and
control acceleration and brake forces, refer to the Pinion Angle Chart in the Parts Lists Section
of this publication.
Longitudinal torque rods
have attaching ends designated as “straddle mount,” “tapered stud,”
or “through bolt” as shown in Figures 6-7. Most can be replaced by pressing out the worn torque
rod bushing and installing a replacement bushing, others require complete torque rod assembly
replacement. See Parts List Section of this publication.
Visually inspect torque rod bushings
for torn or shredded rubber, inspect for bent, cracked, or
broken torque rods, and for end hubs with an elongated “oval” shape. Any of these conditions
will require component replacement.
FIGURE 6-7
SHOCK ABSORBER
Hendrickson uses a long service life, premium shock absorber on all PRIMAAX EX / PRIMAAX
suspensions. If shock absorber replacement is necessary, Hendrickson recommends that the
shock absorbers be replaced with identical Hendrickson Genuine parts for servicing. Failure
to do so will affect the suspension performance, durability, and will void the warranty. Inspection
of the shock absorber can be performed by doing a heat test, and a visual inspection. For
instructions on shock absorber replacement see Component Replacement Section of this pub-
lication. It is not necessary to replace shock absorbers in pairs if one shock absorber requires
replacement.
FIGURE
6-8
HEAT TEST
1. Drive the vehicle at moderate speed on rough
road for minimum of fifteen minutes.
DO NOT GRAB THE SHOCK AS IT COULD POSSIBLY
CAUSE PERSONAL INJURY.
2. Lightly touch the shock body carefully below
the dust cover.
3. Touch the frame to get an ambient reference.
A warm shock absorber is acceptable, a cold
shock absorber should be replaced.
4. To inspect for an internal failure, remove and
shake the suspected shock. Listen for the
sound of metal parts rattling inside. Rattling
of metal parts can indicate that the shock has
an internal failure.
Length
Longitudinal or Transverse Torque Rod
Tapered Stud
Straddle Mount
Longitudinal
Torque Rod
Through Bolt
