HN
®
FR Series
17730-285
15
Preventive Maintenance
BAR PIN END BUSHING
FIGURE
6-5
An indication that the bar pin end bushing requires
replacement is when one or more of the following
conditions apply:
■
Visual inspection of contact area (the flat face
area where bar pin contacts the axle bracket) on
the bar pin reveals signs of excessive wear. If the
thickness of the bar pin in the contact area mea-
sures less than 1.874" (47.59 mm), bar pin end
bushing requires replacement, see Figure 6-5.
■
Visual inspection of the bolt holes in the bar
pin reveals signs of elongation or wear, see
Figure 6-5.
BAR PIN SHIM
FIGURE
6-6
An indication that the bar pin shims
require replacement is when one or
more of the following conditions apply:
■
Visual inspection of contact area
on the shim reveals signs of exces-
sive wear.
■
The thickness of any single leg on
the shim, is less than the measure-
ment shown in Figure 6-6, replacement of bar pin shim is required.
BOLSTER SPRINGS
Inspect all four bolster springs on a periodic basis. Actual bolster spring service condition and
performance may vary depending upon suspension and vehicle configuration, operation,
service and other factors. The following inspection guidelines are intended to assist vehicle
operators and maintenance personnel in examining the bolster springs and determining when
replacements may be needed. In the event one bolster spring on one equalizing beam assem-
bly shows signs of damage or excessive wear, Hendrickson recommends that both bolster
springs installed on that equalizing beam assembly be replaced. When the bolster springs are
replaced on one side only, the vehicle may lean slightly. The new bolster springs will tend to
settle to some degree, and return the vehicle to its original condition. The following procedure is
recommended for proper inspection.
1. Chock the front wheels to prevent movement of the vehicle during inspection of the
suspension.
2. Raise rear of vehicle approximately 4.0" - 5.0", (102 mm - 127 mm) just prior to lifting
wheels off ground, and support with stands.
3. Inspect all bolster springs using the following criteria. If cuts, splits, or bonding separation
are detected in the rubber, measure the depth of the damaged area using a six-inch ma-
chinist scale to determine if replacement is required.
■
Bent, burred or overhanging edges
of the bolster spring metal plates may occur due
to mishandling in service. If the rubber is not trapped, and there are no sharp metal
edges in contact with the free surface of the rubber, this condition is acceptable.
■
Creases
formed by folding of the rubber surface under load are acceptable. These creases
appear as stripes on the surface, polished by wear or covered with tacky rubber.
Bar Pin Mount
If bar pin measurement is
less than
1.874" (47.59 mm)
, component
replacement is required.
1.874"
(47.59 mm)
Rubber
Contact Area
Bolt Hole
Thickness
of
Shim Leg
Minimum
Thickness
Required
1
⁄
8
"
0.123" (3.1 mm)
3
⁄
16
"
0.186" (4.7 mm)
¼"
0.248" (6.3 mm)
3
⁄
8
"
0.371" (9.4 mm)
Pro Gear and Transmission • 906 W. Gore St. Orlando, FL 32805 • 1 (877) 776-4600 / (407) 872-1901 • [email protected]