non Hendrickson fasteners are used, follow the torque specification listed in the vehicle manufacturer’s service manual.

Hendrickson Recommended
Inspection Intervals

Pre-Delivery /
Post conversion
Inspection

First
inspection

Preventive
Maintenance

Within the first
1,000 Miles or
100 Hours

Every 6 Months,
1,200 hours, 25,000
Miles, whichever
comes first

Visual Inspection for proper assembly and function.
Check for all of the following and replace components as
necessary:
• Signs of unusual movement, loose or missing
components
• Signs of abrasive or adverse contact with other
components
• Damaged, or cracked parts
Inspection of fasteners for proper torque as
recommended in the Torque Specification section of
this publication with special attention to the following
suspension connections:

Within the first
100 Miles

• Frame hanger to trailing arm connection
• Equalizing beam end connection
• Torque rods
• Saddle cap to trailing arm connection
Verification of the alignment of axles are within the
vehicle manufacturer’s tolerances

Every 12 Months

Verify proper ride height, refer to the Ride Height in the
Alignment & Adjustments section of this publication

Component Inspection
NOTE

Hendrickson recommends the use of Grade 8 bolts, Grade C locknuts and hardened washers for
all suspension component attachments.
■■ Air spring — Look for chafing or any signs of spring or component damage. Ensure that the upper

bead plate is tight against the underside of the frame. Replace all worn or damaged parts.

■■ Cross tube — Clean the cross tube and inspect it for cracks or excessive wear 8" to 10" from

each end where it enters into the equalizing beam center bushings. Use a straight edge to
check the straightness of the cross tube. If there is a doubt as to fracture, wear or straightness, replacement is necessary.

■■ Shock absorbers — Look for any signs of dents or leakage. Misting is not considered a leak.

See Shock Absorber Inspection in this section.

17730-241

15

Preventive Maintenance

AR2™ 40K • 46K
■■ Equalizing beam assembly, end connection and saddle cap fasteners — Check the overall

condition of the equalizing beam for dents, dings, or other damage. Inspect the equalizing
beam end connection and saddle cap fasteners for proper torque. The beam end connection must sustain proper clamp force of the axle bracket legs to the bushing inner casting
prevent any movement of the beam end connection. See Equalizing Beam End Connection
in this section. See Torque Specifications section of this publication for recommended
torque requirements.

■■ Fasteners — Look for any loose or damaged fasteners on the entire suspension. Make sure

all fasteners are tightened to a torque value within the specified torque range. See Torque
Specifications section of this publication for recommended torque requirements. Use a calibrated torque wrench to check torque in a tightening direction. As soon as the fastener starts
to move, record the torque. Correct the torque if necessary. Replace any worn or damaged
fasteners with genuine specified fasteners. For fasteners not supplied by Hendrickson, see
vehicle manufacturer.

■■ Torque rods — All torque rods must be inspected every six months for looseness, torn or

shredded rubber, bushing walk-out, and for proper fastener torque. If there is metal-to-metal
contact in the bushing joint, this is a sign of excessive bushing wear and the bushing needs
to be replaced.

■■ Wear and damage — Inspect all parts of the suspension for wear and damage. Look for bent

or cracked parts. Replace all worn or damaged parts.

■■ Frame hanger bracket — Check for any signs of loosening or damage at the pivot connec-

tions. Check for cracks, damage, or any signs of looseness at the mounting fasteners. Replace
all worn or damaged parts.

■■ Height control valve and air lines — Check the suspension air system for air leaks. Check

all air lines for proper routing. Check for chafing or pinched air lines. Check the height control
valve linkage for damage or interference with peripheral components. Replace all worn or
damaged parts.

■■ Trailing arm assembly — Check the overall condition of the trailing arm for cracks, dents,

dings, or other damage on the trailing arm assembly. Check the trailing arm bushings for tearing or extreme bulging. Check for any metal to metal contact in the bushed joints. Replace all
worn or damaged parts.

■■ Tire wear — Inspect the tires for wear patterns that may indicate suspension damage or

misalignment. Replace all worn or damaged parts.

See vehicle manufacturer’s applicable publications for other preventive maintenance
requirements.

Beam End Axle Brackets
NOTE

The axle brackets are furnished and welded into position by the vehicle manufacturer or axle
manufacturer.
When an equalizing beam is removed for repair or inspected, check for signs of movement. Also
inspect the axle brackets:
■■ For damage and‌/ ‌or cracks, see Figures 6-1 and 6-2
■■ Measure the two dimensions on the axle bracket legs, see Figure 6‑2

An axle bracket outside of the measurement range, damaged or cracked must be repaired
or replaced. Consult the vehicle manufacturer for inspection, component repair and replacement instructions.

Preventive Maintenance

16

17730-241

AR2™ 40K • 46K
Physical Inspection
■■ Bar Pin Style

1. Inspect the axle brackets for damage or cracks in the locations shown in Figures 6-1 and 6-2.
Any axle bracket that is found damaged or cracked must be repaired or replaced.
2. Measure the distance between the axle bracket legs for correct width, refer to Figures 6-1 and
6-2 for measurement location and dimensions. An axle bracket outside of the measurement
range must be repaired or replaced.
3. Consult the vehicle manufacturer for inspection, component repair and replacement
instructions.
Figure 6-1

Figure 6-2

■■ Adapter Style

1. Inspect the 2½" (64 mm) diameter holes in each of the axle bracket legs as shown in Figure 6-3.
Figure 6-3

2. Remove any burrs or material left there by the
old adapters.
3. Use a new adapter as a gauge for fit, being
sure it enters the holes from the outside of
each bracket leg.
The A dimension between the inside surfaces of the axle bracket legs for beam
end adapter style, as shown in Figure 6‑3
as dimension, must be as in determined in
Table 6-1.
Table 6-1

17730-241

Capacity

End Bushing Length

Dimension A

40K • 46K

5¾"

5.765"± 0.005"

17

Preventive Maintenance

AR2™ 40K • 46K
Equalizing Beam End Connection
An inspection of the beam end connections are necessary when a vehicle is in the shop for major
repair work or every six months, whichever comes first. Periodic visual inspection by the driver and
service personnel is also recommended. Off-highway and severe service operating conditions
require more frequent inspections than on-highway service operation.
NOTE

The equalizing beam end connection requires that the fasteners are tightened to torque specifications to maintain the clamp load of the axle bracket legs to the bar pin. All bushing motion is
accommodated by rubber deflection.

VISUAL Inspection
■■ Bar Pin Style

1. Chock the wheels.
2. Visually inspect suspension components for signs of movement or excessive wear.
■■ Inspect alignment shims in equalizing beam end for looseness. Lightly tap on the align-

ment shims to see if they can be moved. If movement is detected, tighten fasteners to the
proper torque value, see Figure 6-6

■■ Inspect equalizing beam end connection for signs of excessive wear or looseness

SERVICE HINT

An equalizing beam end connection, which is visibly cleaner than the other connections, may
indicate a loose connection.
Figure 6-4

Figure 6-5
■■ Look for worn, frayed or distorted rubber in the bar

pin beam end bushing, see Figure 6-4

■■ Look for the equalizing beam to be lower in the

beam hanger, see Figure 6-4

■■ If the bar pin beam end bushing is visually offset

a floor jack test should be performed. See Jack
Test in this section

Jack Test
1. Place a jack under each beam end as shown. Raise
the jack to check for movement in the connection or
rubber components, see Figure 6-5.

Preventive Maintenance

18

17730-241

AR2™ 40K • 46K
NOTE

The gap at each side of the visible rubber on the lower part of the bar pin end bushing is normal,
see Figure 6-5, and is not an indication to replace the bushing. Because all rubber end bushings
are in compression, with the load bearing on the top side, the lower side of the rubber is slightly
relieved, allowing the rubber to move inward, and a gap appears.

Physical INSPECTION
■■ Bar Pin Style

If bar pin movement or looseness is noted in the equalizing beam end hub, do not
operate the vehicle. Replace the rubber end bushings and all connecting parts.
The above condition can result in costly repair, downtime, possible separation of
components, Adverse Vehicle Handling, property damage, or personal injury.

Note

An equalizing beam end connection that is visibly cleaner than the other connections may indicate a loose connection.
2. If bar pin end bushing movement or looseness is detected in the equalizing beam end hub,
replace the end bushings and all connecting parts. Refer to the Component Replacement
section of this publication.
3. Check and record torque values for each 1" bar pin fastener, see Figure 6-6. Ensure all fasteners are tightened to the following:
■■ At the locknuts tighten to
525 ± 75 foot pounds torque
■■ At the bolt head tighten to

575 ± 75 foot pounds torque
4. Recheck equalizing beam end connections for signs of looseness.
■■ Inspect alignment shims in equalizing beam end for looseness. Lightly tap on the align-

ment shims to see if they can be moved. If movement is detected, tighten fasteners to the
proper torque value, see Figure 6-6
■■ Inspect equalizing beam end connection for signs of excessive wear or looseness
5. If bar pin looseness is still detected in the equalizing beam end hub, DO NOT operate the
vehicle. One or more components will require replacement, see Component Replacement
section of this publication.
Figure 6-6

17730-241

19

Preventive Maintenance

AR2™ 40K • 46K
VISUAL Inspection
■■ Adapter Style

1. Chock the wheels.
2. Visually inspect suspension components for signs of movement or excessive wear.
■■ Inspect equalizing beam end connection for signs of excessive wear or looseness
■■ Look for worn, frayed or distorted rubber in the beam, see Figure 6-4
■■ Look for the equalizing beam to be lower in the axle bracket, see Figure 6-4
■■ If it is visually offset a jack test should be performed. Place a jack under each beam end

as shown. Raise the jack to check for movement in the connection or rubber components,
see Figure 6-5
Figure 6-7

3. The beam end adapter style connections have
an adapter flange with a flat side for assembly
clearance with the axle housing bowl.
■■ The flat must be positioned vertically as

shown in Figure 6-7. If the flat of the adapter
position is incorrect, removal of the fasteners will be necessary to correct position,
refer to the Adapter Style End bushings in the
Component Replacement section

Physical INSPECTION
■■ Adapter Style

If bushing movement or looseness is noted in the equalizing beam end hub, do not
operate the vehicle. Replace the rubber end bushings and all connecting parts.
The above condition can result in costly repair, downtime, possible separation of
components, Adverse Vehicle Handling, property damage, or personal injury.

Service hint

An equalizing beam end connection that is visibly cleaner than the other connections may indicate a loose connection.
1. If bushing movement or looseness is detected in the equalizing beam end hub, DO NOT operate vehicle. Replace the equalizing beam end bushings and all connecting parts. Refer to the
Component Replacement section of this publication.
2. Check and record torque values, see Figure 6-8. Ensure all fasteners are tightened to the
following:
■■ 40K —

225 ± 15 foot pounds torque

■■ 46K —

470 ± 25 foot pounds torque

3. Recheck equalizing beam end connections for signs of looseness.
FIGURE 6-8

Preventive Maintenance

20

17730-241

AR2™ 40K • 46K
Bar Pin End Bushing
Figure 6-9

An indication that the bar pin end bushing
requires replacement is when one or more of
the following conditions apply:
Visual inspection of:
■■ Contact areas (the flat face areas where

bar pin contacts the axle bracket) on the
bar pin reveals signs of excessive wear

■■ The bolt holes in the bar pin reveals signs

of elongation or wear, see Figure 6-9

Bar pin replacement is required, see Figure 6-9,
if the bar pin thickness measures less than:
■■ With shims — 1.874" (47.59 mm)
■■ Without shims — 2.252" (57.2 mm)

Bar Pin Shims
An indication that the bar pin shims require replacement is when one or more of the following
conditions apply:
■■ Visual inspection of contact areas on the shim reveals signs of excessive wear
■■ The thickness of any single leg on the shim, is less than the measurement shown in

Figure 6-10, replacement of bar pin shim is required

Figure 6-10
Original
Thickness
of Shim Leg

Minimum
Thickness
Required

Part Number

1

⁄8" (3.2 mm)

0.123" (3.1 mm)

50131-000

3

⁄16" (4.8 mm)

0.186" (4.7 mm)

50130-000

¼" (6.4 mm)

0.248" (6.3 mm)

50131-000

⁄8" (9.5 mm)

0.371" (9.4 mm)

57026-000

3

Rubber Center Bushing
An inspection of the center bushing is necessary when a vehicle is in the shop for major repair
work or every twelve months. Look for:
■■ Any metal to metal contact
■■ Worn, frayed, or distorted rubber in the center bushing
■■ The bushing inner metal that is not centered in the bushing
■■ Any equalizing beam to saddle contact

17730-241

21

Preventive Maintenance

AR2™ 40K • 46K
Frame Hanger to Trailing Arm Connection
If more than half the thickness of the rubber of the trailing arm bushing is diminished replacement
is recommended. For trailing arm bushing replacement, refer to the Component Replacement
section in this publication.
FIGURE 6-11
■■ The flat must be positioned vertically as

shown in Figure 6-11. If the flat of the
adapter position is incorrect, removal of
the fasteners will be necessary to correct position.

Physical INSPECTION
If TRAILING ARM bushing movement or
looseness is noted in the Trailing arm
end hub, do not operate the vehicle.
Replace the rubber trailing arm
bushings and all connecting parts. The
above condition can result in costly
repair, downtime, possible separation
of components, Adverse Vehicle Handling, property damage, or personal injury.

1. If trailing arm bushing movement or looseness is detected in the trailing arm end hub, DO NOT
operate the vehicle. Replace the trailing arm bushings and all connecting parts. Refer to the
Component Replacement section of this publication.
2. Check and record torque values, tighten 1" fasteners to 470 ± 25 foot pounds torque, see
Figure 6-11.

Longitudinal and Transverse Torque Rods
The AR2 SUSPENSION Incorporates longitudinal and TRANSVERSE 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,
Adverse Vehicle Handling, POSSIBLE TIRE CONTACT WITH THE FRAME, PREMATURE COMPONENT
DAMAGE, OR SEVERE PERSONAL INJURY.

All torque rods need to be inspected for looseness by one of the following methods.
■■ Method 1 — For Tractor applications only with brakes applied, slowly rock the empty vehicle

with power while a mechanic visually checks the action at both ends

■■ Method 2 — with the vehicle shut down, a lever check can be made with a long pry bar placed

under each rod end and pressure applied

Visually inspect torque rod bushings for torn or shredded rubber, inspect for bent, cracked, or
broken torque rods and also for end hubs that have an ­elongated “oval” shape. Any of these conditions require component replacement. If there is metal-to-metal contact, this is a sign of excessive
bushing wear and the bushing needs to be replaced.
NOTE

The lengths of the torque rods are determined by the vehicle manufacturer. Refer to vehicle manufacturer’s service instructions for the proper torque rod length.
The lengths of these torque rods may be fine tuned by adding or removing shims at the straddle mount
end of the torque rods in order to correct drive line angles or axle centering under the frame. The
transverse torque rods center the axles under the frame and control axle walk-out during cornering.
A two-piece torque rod is also available to cut and weld to the desired length, see Hendrickson
publication No. 45745‑148.
The mounting brackets at the axle ends of the torque rods are furnished and welded into position
on the axle housings by the vehicle manufacturer or the axle manufacturer.

Preventive Maintenance

22

17730-241

AR2™ 40K • 46K
Figure 6-12

Both types of rods may have torque
rod bushings designated “straddle
mount” or “tapered stud” as shown
in Figure 6-12. Both types can be
replaced by pressing out the worn
bushing and installing a new genuine Hendrickson bushing. For proper
replacement instructions, refer to the
Component Replacement section in
this publication.
It is important to check the torque rod fasteners for proper torque values, refer to the Torque
Specifications section in this publication.
NOTE

Hendrickson recommends Grade 8 bolts, hardened flat washer and Grade C locknuts be used for
all straddle mount torque rods.

Saddle Connection
Visually inspect for any signs of movement or looseness. Ensure:
■■ Each saddle is centered on each equalizing beam center bushing
■■ The center bushing inner metal is full seated to the saddle
■■ The saddle cap fasteners are tightened to the proper torque, see Figure 6-13. Saddle cap

fasteners have a phosphate oil coating

THE TRAILING ARM Assemblies are ATTACHED TO THE CENTER BUSHINGS OF EACH EQUALIZING BEAM
WITH TWO (2) SADDLE CAPS. EACH SADDLE CAP USES TWO (2) studs TO CLAMP THE CENTER BUSHING
INNER METAL TO THE SADDLE. THE SADDLE CAPS MUST BE INSTALLED and tighten SO THAT THERE IS
AN EVEN GAP BETWEEN THE SADDLE CAPS AND THE BASE OF THE TRAILING ARM ASSEMBLY AS SHOWN
IN FIGURE 6-13. IF THEY ARE NOT INSTALLED properly,THE TRAILING ARM Assemblies COULD BECOME
DEFORMED, RESULTING IN BENT BOLTS OR assembly DAMAGED.
LOOSE OR OVER TORQUED FASTENERS CAN CAUSE COMPONENT DAMAGE, Adverse Vehicle
Handling, PROPERTY DAMAGE, OR SEVERE PERSONAL INJURY. MAINTAIN CORRECT TORQUE values
AT ALL TIMES. CHECK TORQUE VALUES ON A REGULAR inspection interval.
Figure 6-13

17730-241

23

Preventive Maintenance

AR2™ 40K • 46K
Figure 6-14

1. While tightening the saddle cap stud fasteners maintain an even gap
between the saddle assembly base and the saddle cap, see Figure 6-14.
2. Center the saddle on the equalizing beam center bushing.
3. Tighten the saddle cap fasteners evenly in 50 foot pounds increments to
250 ± 25 foot pounds torque in the proper sequence to achieve uniform bolt tension as shown in Figure 6‑14 until the final torque value is
achieved. DO NOT exceed specified torque on saddle cap fasteners.

Cross Tube
IMPROPER JACKING METHODS CAN CAUSE STRUCTURAL DAMAGE which CAN CAUSE Adverse
Vehicle Handling, PROPERTY DAMAGE OR SEVERE PERSONAL INJURY AND WILL VOID