9. Verify the axle’s alignments are within the vehicle manufactures tolerance.
10. Set brakes and remove wheel chocks.
Figure 7-10

Alignment & Adjustments

34

17730-241

AR2™ 40K • 46K
SECTION 8

Component Replacement
Fasteners
Hendrickson recommends when servicing the vehicle, replace all removed fasteners with new
equivalent fasteners. Maintain correct torque values at all times. Check torque values as specified.
See Hendrickson’s Torque Specifications section of this publication. If non-Hendrickson fasteners
are used, follow torque specifications listed in the vehicle manufacturer’s service manual.
NOTE

Hendrickson recommends the use of Grade 8 bolts and Grade C locknuts. If flange head bolts
and locknuts are not used then hardened structural washers must be used under bolt heads
and locknuts.

Frame Hanger
Figure 8-1

Disassembly
1. Chock the front wheels.
2. Support the frame of the vehicle at ride height.
PRIOR TO AND DURING DEFLATION AND INFLATION OF THE AIR SUSPENSION SYSTEM, ENSURE THAT ALL
PERSONNEL AND EQUIPMENT ARE CLEAR FROM UNDER THE VEHICLE AND AROUND THE SERVICE AREA,
FAILURE TO DO SO CAN CAUSE SERIOUS PERSONAL INJURY, DEATH, OR PROPERTY DAMAGE.

3. See Air Spring Cautions and Warnings in the Important Safety Notice section of this publication prior to deflating or inflating the suspension system.
4. Lower the leveling valve arm(s) to exhaust the air in the air springs and deflate the rear
suspension.
5. Remove trailing arm bushing fasteners and the adapter assembly, see Figure 8-1.
6. Raise the frame to allow clearance in between frame hanger and trailing arm.
7. Support the frame with frame stands.
8. Push trailing arm out of the frame hanger.
9. Remove the fasteners that attach the frame hanger to the vehicle per vehicle manufacturer’s
specifications.

17730-241

35

Component Replacement

AR2™ 40K • 46K
10. Remove frame hanger and spacer plate (supplied by vehicle manufacturer) located between
the frame hanger and lower cross member flange.
11. Inspect the trailing arm bushing for wear or damage, refer to the Preventive Maintenance section of this publication. Replace as necessary.

Assembly
1. Install the frame hanger.
2. Install the spacer plate (supplied by vehicle manufacturer) between the bottom of the frame
hanger and lower cross member flange.
3. Clamp the bottom of the frame hanger to the cross member flange.
FAILURE TO CLAMP THE FRAME HANGER AGAINST THE UNDERSIDE OF THE FRAME WHILE TIGHTENING THE
FRAME BOLTS CAN RESULT IN COMPONENT DAMAGE AND PERSONAL INJURY OR PROPERTY DAMAGE.

4. Install the fasteners that attach the frame hanger to the vehicle frame web and snug the bolts.
5. Install the frame hanger fasteners that attach the frame hanger to the spacer plate and cross
member and snug the bolts.
6. Tighten all frame hanger fasteners to the vehicle manufacturer’s torque specification and
remove the clamp.
7. If raised, lower the frame rail back to ride height. Position the trailing arm into the new frame
hanger.
8. Install the trailing arm bushing fasteners and adapter assembly.
9. Tighten trailing arm bushing locknut to

470 ± 25 foot pounds torque.

10. See additional Air Spring Cautions and Warnings in the Important Safety Notice section of this
publication prior to deflating or inflating the air system.
11. Connect the height control valve linkage rod(s) to the height control valve arm(s) to inflate the
suspension properly.
12. Remove frame supports.
13. Remove the wheel chocks.

Trailing Arm
Disassembly
1. Chock the wheels
PRIOR TO AND DURING DEFLATION AND INFLATION OF THE AIR SUSPENSION SYSTEM, ENSURE THAT ALL
PERSONNEL AND EQUIPMENT ARE CLEAR FROM UNDER THE VEHICLE AND AROUND THE SERVICE AREA,
FAILURE TO DO SO CAN CAUSE SERIOUS PERSONAL INJURY, DEATH, OR PROPERTY DAMAGE.

2. See Air Spring Cautions and Warnings in the Important Safety Notice section of this publication prior to deflating or inflating the suspension system.
3. Lower the leveling valve arm(s) to exhaust the air in the air springs and deflate the rear
suspension.
4. Lift and support the axles with safety stands.
5. Remove the tires.
6. Remove saddle cap fasteners and disconnect the saddle caps from trailing arm.
7. Disconnect the shock absorber from the trailing arm.
8. Disconnect the air lines from the air springs.
9. Remove upper and lower air spring fasteners.
10. Raise the frame to full suspension rebound travel.
Component Replacement

36

17730-241

AR2™ 40K • 46K
THE WEIGHT OF THE TRAILING ARM ASSEMBLY IS APPROXIMATELY 225 POUNDS (102 kilograms).
CARE SHOULD BE TAKEN AT REMOVAL AND INSTALLATION TO PREVENT PERSONAL INJURY OR DAMAGE
TO COMPONENTS.

11. Remove air springs.
12. Remove trailing arm fasteners and adapters from the frame hangers.
13. Lift trailing arm off center bushing and remove from vehicle.

Assembly
THE WEIGHT OF THE TRAILING ARM ASSEMBLY IS APPROXIMATELY 225 POUNDS (102 kilograms).
CARE SHOULD BE TAKEN AT REMOVAL AND INSTALLATION TO PREVENT PERSONAL INJURY OR DAMAGE
TO COMPONENTS.

1. Raise frame high enough to allow adequate clearance of trailing arm between the frame and
the center bushing.
2. Position the trailing arm between the frame and the equalizing beam center bushing.
3. Carefully lower the trailing arm until it is seated on the equalizing beam center bushing, see
Figure 8-2.
4. Install the trailing arm saddle caps, see Figure 8-2. DO NOT tighten at this time.
SERVICE HINT

If needed, tip the front of the trailing arm down to allow clearance for the front hanger. It may be
necessary to install a block of wood behind the trailing arm to keep it from tipping backwards, see
Figure 8-2.
Figure 8-2

5. Install the trailing arm into the front hanger.
6. Install the trailing arm bushing adapter and fasteners. DO NOT tighten at this time.
7. Rotate the adapter so that the cutoff flats are vertical.
8. Install the air springs. Air spring stud is on the outboard side of the frame rail.
9. Lower frame to proper ride height.
10. Install ¾" x 7¼" lower shock mounting bolt and washer from the inboard side into the trailing
arm and the shock absorber. Install outboard washer and locknut, see Figure 8-3.
11. Tighten the upper and lower shock eye locknuts to
Figure 8-3.
12. Tighten the air spring upper ¾" locknut to
to 25 ± 5 foot pounds torque.

17730-241

37

60 ± 10 foot pounds torque, see

60 ± 10 foot pounds torque and lower ½" locknut

Component Replacement

AR2™ 40K • 46K
Figure 8-3

13. Tighten the saddle cap locknuts to
250 ± 25 foot
pounds torque.
Note

Ensure the trailing arm bushing
adapter flats are vertical, see
Figure 8-4.
14. Tighten the bushing adapter
locknuts to 470 ± 25 foot
pounds torque, see Figure 8-2.
15. See Air Spring Cautions and
Warnings in the Important
Safety Notice section of this
publication prior to deflating
or inflating the suspension
system.
16. Connect the height control
valve linkage(s) to the height
control valve arm(s) to inflate
the suspension.
Figure 8-4

17. Inflate the suspension slowly and verify
that the air spring bladder inflates uniformly without binding.
18. Verify proper ride height, refer to Ride
Height in the Alignment & Adjustments
section of this publication.
19. Remove the wheel chocks.

Trailing Arm Bushing
You will need
■■ A shop press with a capacity of at least 100 tons
■■ Adapter set tool — (Hendrickson Part No. 66086-102) – Refer to Special Tools section of this

publication for the tools to remove and install the trailing arm bushings

■■ Receiving tool — The receiving tool is a shop made tool which completely supports the beam

hub being serviced and is tall enough to receive the bushing as it is being pressed in or out,
see Special Tools section of this publication

DISCARD USED FASTENERS. ALWAYS USE NEW FASTENERS TO COMPLETE A REPAIR. FAILURE TO DO SO
COULD RESULT IN FAILURE OF THE PART OR MATING PARTS, Adverse Vehicle Handling, PERSONAL
INJURY, OR PROPERTY DAMAGE.

NOTE

Component Replacement

Hendrickson recommends the use of Grade 8 bolts and Grade C locknuts. If flange head bolts
and locknuts are not used then hardened structural washers must be used under bolt heads
and locknuts.

38

17730-241

AR2™ 40K • 46K
DISASSEMBLY
1. Remove the trailing arm assembly from the vehicle. Follow the Trailing Arm Disassembly procedure in this section.
Do not use a cutting torch to remove any fasteners or bushings. The use of heat
on suspension components will adversely affect the strength of these parts. A
component damaged in this manner can result in the Adverse Vehicle Handling and
possible personal injury or property damage.

2. Place the trailing arm assembly in a shop press with the equalizing beam center hub firmly
supported on the press bed.
3. Install the trailing arm bushing removal tool Part no. 66086-102 (OTC 1764) centered on the
trailing arm bushing.
4. Push directly on trailing arm bushing removal tool until the trailing arm bushing is pressed out
of the trailing arm bore.

INSPECTION
After removing the trailing arm bushings, thoroughly inspect the trailing arm bushing bores. If
damaged from trailing arm bushing removal, replace with a new trailing arm. DO NOT re-bush or
otherwise use trailing arm that has been damaged.
Failure to replace trailing arm that has been damaged from bushing removal can result
in the failure of that trailing arm, leading to Adverse Vehicle Handling and possible
personal injury or property damage.

When installing rubber trailing arm bushings the following steps will minimize the chance of
damaging a new bushing:
1. Clean the bushing bores of the trailing arm with emery cloth, removing any nicks or metal
buildup from bushing removal.
2. Measure the inside diameter of the trailing arm’s bushing bore and the trailing arm bushing’s
outside diameter.The specification of the trailing arm’s bushing bore on a new AR2 trailing arm:
■■ Inside Diameter — 4.365" ± 0.004" (110.86 mm ± 0.10 mm)
■■ Outside Diameter — 4.376"± 0.002" (111.15 mm ± 0.05 mm)

Each measurements is to be taken as the mean of any two readings at 90 degrees in the
same plane, see Figure 8-5. If either component is not within the specified range, replacement is required.
Figure 8-5

3. The trailing arm bushing bore may have a more substantial lead chamfer at one end of the
bore than the other. Take advantage of the larger chamfer by pressing in the new trailing arm
bushing from this end.

17730-241

39

Component Replacement

AR2™ 40K • 46K
4. Support the trailing arm squarely at the bore area to avoid distortion of the trailing arm bushing bore or bending of the trailing arm.
5. Lubricate the outer diameter (O.D.) of the trailing arm bushing and the inner diameter (I.D.)
of the trailing arm bushing bore with an NLGI#2 – EP (Extreme Pressure) lithium base grease.
6. Make sure the bushing is square to the trailing arm bore and press the bushing into trailing arm.

ASSEMBLY
1. Place the trailing arm in a shop press on the receiving tool.
2. Support the trailing arm squarely at the bore area to avoid distortion of the trailing arm bushing bore or bending of the trailing arm.
3. Lubricate the trailing arm bushing bore and the trailing arm bushing’s outer metal sleeve with
an NLGI#2 – EP (Extreme Pressure) lithium base grease.
4. Install the trailing arm bushing installation tool and press in the new trailing arm bushing until
the outer metal sleeve is centered in the trailing arm’s bushing bore.
5. Install the trailing arm assembly to the vehicle. Follow the trailing arm installation procedure
in this section.

Air Spring
It is not mandatory to replace both air springs on the same trailing arm if one (1) air spring
requires replacement.
NOTE

The following component replacement procedure is for one (1) air spring replacement. Duplicate
procedure if more that one air spring requires replacement.

DISASSEMBLY
1. Chock the front wheels.
2. Support the frame of the vehicle at ride height.
IMPORTANT NOTE

If the air springs are deflated it will be necessary to raise the frame of the vehicle to an acceptable
height to allow for removal of the air spring(s).
3. Disconnect the height control linkage assembly from the leveling valve arm by sliding the
rubber grommet from the stud(s).
PRIOR TO AND DURING DEFLATION AND INFLATION OF THE AIR SUSPENSION SYSTEM, ENSURE THAT ALL
PERSONNEL AND EQUIPMENT ARE CLEAR FROM UNDER THE VEHICLE AND AROUND THE SERVICE AREA,
FAILURE TO DO SO CAN CAUSE SERIOUS PERSONAL INJURY, DEATH, OR PROPERTY DAMAGE.

4. See Air Spring Cautions and Warnings in the Important Safety Notice section of this publication prior to deflating or inflating the suspension system.
5. Lower the leveling valve arm(s) to exhaust the air in the air springs and deflate the rear
suspension.
6. Remove the air line from the air spring.
7. Remove the two (2) ½" locknuts from the lower air spring studs on the underside of the trailer
arm, see Figure 8-6.
8. Remove the ¾" nylocknut from the upper air spring mounting stud, see Figure 8-6.
9. Remove the air spring.

Component Replacement

40

17730-241

AR2™ 40K • 46K
INSPECTION
1. Inspect the mounting surfaces on the trailing arm and the upper air spring mounting bracket
for cracks or damage. Replace as necessary.

ASSEMBLY
1. Install the ½" studs in the bottom of the new air spring and tighten to
pounds torque.

25 ± 5 foot

2. Assemble the air spring to air spring frame hanger by inserting studs into appropriate holes.
The ¾" combo stud faces outboard of the vehicle.
Figure 8-6

3. Install the air spring into the
trailing arm assembly by
inserting the studs into the
trailing arm mounting holes,
see Figure 8-6.
SERVICE HINT

Depending on the frame height
of the vehicle it may be necessary to compress the air spring
to facilitate installation into the
frame bracket and trailing arm.
4. Assemble the washers and
locknuts which connect the
air spring to the trailing arm
assembly and tighten the
25 ± 5 foot
locknuts to
pounds torque as shown in
Figure 8-6.
5. Assemble the washers and
locknuts on the combo stud which connect air spring to the frame hanger bracket. Tighten the
combo stud locknut to 60 ± 10 foot pounds torque as shown in Figure 8-6.
6. Install the air fitting to the air spring using Teflon thread seal.
7. Install the air lines to the air springs.
8. Lower the frame of vehicle.
9. See Air Spring Cautions and Warnings in the Important Safety Notice section of this publication prior to deflating or inflating the suspension system.
10. Inflate the suspension by connecting the height control valve linkage(s) to the leveling
valve arm(s).
11. Verify the air springs inflate uniformly without binding and that the vehicle air system is at the
correct operating air pressure.
12. Remove the frame supports.
13. Verify proper ride height, refer to Ride Height in the Alignment & Adjustments section of this
publication.
14. Remove the wheel chocks.

17730-241

41

Component Replacement

AR2™ 40K • 46K
Shock Absorber
NOTE

It is not necessary to replace shock absorbers in pairs if only one (1) shock absorber requires
replacement.

DISASSEMBLY
1. Remove the lower mounting bolts, fasteners, and spacer.
2. Remove the upper locknut and washer.
3. Slide the shock absorber off the upper mounting bolt.
4. Inspect the shock absorber mounting brackets and hardware for damage or wear, replace as
necessary, see the Preventive Maintenance section of this publication.

ASSEMBLY

Figure 8-7

1. Install the shock absorber
onto the upper mounting bolt,
see Figure 8‑7.
2. Install the washers and locknut, DO NOT tighten at this
time.
3. Install ¾" x 7¼" lower shock
mounting bolt and washer
from the inboard side into
the trailing arm and the
shock absorber. Install outboard washer and locknut,
see Figure 8-7.
4. Tighten both shock eye locknuts to 60 ± 10 foot pounds
torque, see Figure 8-7.

Height Control Valve
DISASSEMBLY
1. Chock the wheels of vehicle.
2. Disconnect the leveling valve arm(s) from the rubber grommet(s).
PRIOR TO AND DURING DEFLATION AND INFLATION OF THE AIR SUSPENSION SYSTEM, ENSURE THAT ALL
PERSONNEL AND EQUIPMENT ARE CLEAR FROM UNDER THE VEHICLE AND AROUND THE SERVICE AREA,
FAILURE TO DO SO CAN CAUSE SERIOUS PERSONAL INJURY, DEATH, OR PROPERTY DAMAGE.

3. See Air Spring Cautions and Warnings in the Important Safety Notice section of this publication prior to deflating or inflating the suspension system.
4. Lower the leveling valve arm(s) to exhaust the air in the air springs and deflate the rear
suspension.
5. Remove the air lines from the height control valve.
6. Remove and discard the locknut fasteners that attach the height control valve to the frame
mounting bracket. DO NOT back out the studs from the height control valve body. Loosening
the studs may cause the height control valve to leak.
7. Remove height control valve, see Figure 8-8.
8. Remove the air fittings from the height control valve.

Component Replacement

42

17730-241

AR2™ 40K • 46K
Figure 8-8

ASSEMBLY
1. Install the air fittings into the new
height control valve using Teflon
thread seal.
2. Install the height control valve to
the frame mounting bracket by
attaching the ¼" washers and
locknuts. Tighten to 9 ± 1 foot
pounds torque, see Figure 8-8.
3. Install the air lines to the height
c o n t ro l va l ve. R e fe r to t h e
Plumbing Diagram section of this
publication.
4. See Air Spring Cautions and
Warnings in the Important Safety
Notice section of this publication
prior to deflating or inflating the
suspension system.
5. Inflate the suspension by connecting the height control valve linkage(s) to the leveling valve arm(s).
6. Verify the air springs inflate uniformly without binding and that the vehicle air system is at the
correct operating air pressure.
7. Verify proper ride height, refer to Ride Height in the Alignment & Adjustments section of this
publication.
8. Remove the wheel chocks.

Equalizing Beam
SERVICE HINT

It is recommended to remove both equalizing beams and the cross tube as a group even if only
one (1) equalizing beam needs service.

DISASSEMBLY
1.
2.
3.
4.
5.

Chock the wheels of the steer axle.
Raise and support the drive axles with safety stands.
Remove the tires.
Support the pinion angle of the drive axles to prevent axle movement during service.
Remove the saddle cap fasteners from both inboard and outboard sides of both equalizing
beam’s center bushings.
6. Remove the saddle caps, see Figure 8-9.
7. Raise the vehicle’s frame just enough to create a ½" (13 mm) gap between the saddles and
the center bushings. Support the vehicle’s frame at this height.

THE WEIGHT OF THE equalizing beam ASSEMBLY IS APPROXIMATELY 155 POUNDS. Prior to
removing the beam end fasteners from the equalizing beam, support the end of the
equalizing beam to prevent from dropping. CARE SHOULD BE TAKEN AT REMOVAL AND
INSTALLATION TO PREVENT PERSONAL INJURY OR DAMAGE TO COMPONENTS.

17730-241

43

Component Replacement

AR2™ 40K • 46K
Figure 8-9

Figure 8-10

8. Support both equalizing beams
with a floor jack.
9. Remove and discard beam end
attaching fasteners.
Note

Prior to disassembly of the equalizing
beam bar pin fasteners, note the orientation of the bar pin alignment shims,
see Figure 8-10. It is required that the
bar pin alignment shims are installed
in the same orientation and location
as removed to preserve the existing
vehicle alignment. Improper vehicle
alignment can increase tire wear.
Prior to removing both equalizing
beams, support the pinion of
each drive axle. Failure to do so
can result in personal injury or
allow the axles to shift making
reassembly more difficult.

10. Slowly lower the floor jacks and remove the equalizing beams from the axle brackets.
11. Slide the equalizing beams off the cross tube and out from under the vehicle.
12. Remove the floor jacks from under the equalizing beams.

ASSEMBLY
1. Position the equalizing beams under the axles with a floor jack under the center of each
equalizing beam.
2. Install the cross tube into the center bushing of each equalizing beam.
SERVICE HINT

Component Replacement

Ensure the equalizing beam’s center bushing end plug is located on the outboard side, see
Figure 8-11.

44

17730-241

AR2™ 40K • 46K
Figure 8-11

Note

The center bushing must have
the end plug welded into
position when the cross tube
is in position.

SERVICE HINT

Increasing or decreasing the
pinion angle may help align
the axle bracket and equalizing
beam end bushings.
3. Using the floor jacks, slowly
raise the equalizing beams
and cross tube as an
assembly into the axle brackets. Ensure that each equalizing beam end bushings correctly
engages the axle brackets.

NOTE