■■

Vehicle ride height for both the front and rear are within specification. Follow m
­ anufacturer’s
guidelines (if equipped).

■■

Front and rear spring mounts are free of wear or damage.

INSPECT TIE ROD ENDS
Perform Tie Rod Inspection procedure; refer to the Preventive Maintenance Section of this
publication.

REAR AXLE AND REAR SUSPENSION
The rear axle can cause front tire wear. If the outer edge of one front tire is worn and the inner
edge of the other front tire is worn, check the following:
■■

Make sure the rear axle (especially a tandem axle) is correctly aligned. Refer to the procedure
dictated by the vehicle or suspension manufacturer.

■■

All fasteners including U-bolts (if applicable) are installed and tightened to the specified
torque.

■■

The leaf springs are not worn or damaged.

■■

The bushings in the leaf springs are not worn or damaged.

■■

The torque rods (if used) are correctly adjusted (if adjustable).

■■

The frame is not bent or twisted.

■■

Refer to any additional recommendations and specifications from the manufacturer of vehicle
on rear axles and suspensions. Reference The Technology & Maintenance Council (TMC)
Guidelines for Total Vehicle Alignment.

FRONT WHEEL ALIGNMENT
Hendrickson recommends technicians review The Technology & Maintenance Council’s publication (TMC) “Guidelines for Total Vehicle Alignment” (TMC RP 642).
Check total (front and rear) vehicle wheel alignment when any of the following occurs:
■■

Every 80,000 to 100,000 miles, or 12-18 months (normal maintenance).

■■

When the vehicle does not steer correctly.

■■

To correct a tire wear condition.

For rear wheel alignment specifications and adjustments refer to the vehicle manufacturer.
The front wheel alignment specifications can be found in the Alignment Specifications Section of
this publication. There are two types of front wheel alignment:
1. Minor alignment – a minor front wheel alignment is done for all normal maintenance conditions, see below.
2. Major alignment – a major alignment is done when uneven or excessive tire wear is evident,
or response at the steering wheel is sluggish, or the need for major wheel alignment check
and adjustment is required, see below.

MINOR FRONT WHEEL ALIGNMENT
Perform the minor front wheel alignment in the following sequence:
1. Inspect all systems that affect wheel alignment. Refer to the Inspection Prior to Alignment in
this section.
2. Check the wheel bearing end play.
3. Check and adjust toe.

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25

Alignment & Adjustments

STEERTEK NXT High Capacity Steer Axle System for Autocar® ACX-XPEDITOR™ Vehicles
4. Check and adjust the vehicle ride height as specified in the Preventive Maintenance Section
of this publication.

MAJOR FRONT WHEEL ALIGNMENT
Be certain to follow wheel alignment inspection intervals as specified by the original equipment
manufacturer. Before performing a major front wheel alignment it is recommended that alignment
equipment calibration be checked to ensure proper vehicle alignment.
Major wheel alignment is accomplished in the following sequence of operation:
1. Inspect all the systems that influence the wheel alignment. Refer to the Inspection Prior to
Alignment in this section.
2. Check and adjust the maximum turn angle, refer to the Steering Stop Adjustment Procedure in
this section, see Figures 8-11 and 8-12.
FIGURE 8-11

FIGURE 8-12

3. If the vehicle is equipped with power steering, check the pressure relief in the power steering system and reset if necessary. Refer to the vehicle manufacturer regarding the subject:
Adjusting the Pressure Relief in the Power Steering System.
4. Check the turning angle. Refer to the original equipment manufacturer specifications.
5. Check the kingpin (or steering axis) inclination. Refer to Kingpin Inclination under Alignment
Definitions in this section.
AXLE CAMBER IS NOT ADJUSTABLE. DO NOT CHANGE THE AXLE CAMBER ANGLE OR BEND THE
AXLE BEAM. BENDING THE AXLE BEAM TO CHANGE THE CAMBER ANGLE CAN DAMAGE THE AXLE AND
REDUCE AXLE STRENGTH, AND WILL VOID HENDRICKSON’S WARRANTY. A BENT AXLE BEAM CAN
CAUSE LOSS OF VEHICLE CONTROL, POSSIBLY CAUSING PERSONAL INJURY OR PROPERTY DAMAGE,
SEE FIGURE 8-13.

6. Check camber angle. DO NOT attempt to adjust camber. Refer to “Camber” under the
Alignment Definitions in this section.
FIGURE 8-13

Alignment & Adjustments

26

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STEERTEK NXT High Capacity Steer Axle System for Autocar® ACX-XPEDITOR™ Vehicles
7. It is necessary to verify that all ride heights (front and rear) are within specifications prior to
checking caster to get an accurate caster reading.
8. Check and adjust caster angle. Refer to Caster Angle under Alignment Definitions in this section.
NOTE

The use of two different angle caster shims will not change cross caster. Cross caster is the difference between the caster readings for left and right side of the vehicle.
9. Check and adjust toe-in, refer to “Toe Setting” in this section.

STEERING STOP

FIGURE 8-14

ADJUSTMENT PROCEDURE
When the axle or steering knuckle is replaced,
the steering stop adjustment must be checked.
The steering stop adjustment procedure is as
follows:
1. Drive truck onto turntables and chock the
rear wheels.
2. Measure the wheel cut. The wheel cut is
determined by steering the tires. Wheel cut
is measured at the inside wheel only, therefore the tires must be turned to the full lock
position for each right hand and left hand
direction. Refer to the vehicle manufacturer
for exact specifications.

Ensure the sides of
square head axle stops
are set parallel to the
axle beam

3. Increase the wheel cut by loosening the jam nuts and screw the axle stops in clockwise.
4. Tighten the jam nuts.
NOTE

It is very important that the sides of the square head axle stops are set parallel to the axle beam
to ensure a good contact point on the axle, see Figure 8-14.
5. Decrease the wheel cut by loosening the jam nuts and screw the axle stops out
counter-clockwise.
6. Tighten the jam nuts to

50 ± 10 foot pounds torque.

7. Measure the wheel cut and check for any interference with related steering components.
ALWAYS CHECK / RESET THE STEERING GEAR BOX POPPETS WHEN THE WHEEL CUT IS DECREASED.
FOLLOW MANUFACTURER’S GUIDELINES FOR THE GEAR BOX POPPET RESETTING PROCEDURE.
FAILURE TO DO SO CAN RESULT IN PREMATURE FAILURE OF THE AXLE OR STEERING KNUCKLE. THIS
CONDITION CAN CAUSE LOSS OF VEHICLE CONTROL, PERSONAL INJURY OR PROPERTY DAMAGE AND
VOID ANY APPLICABLE WARRANTY.

TOE SETTING
1. Place the vehicle on a level floor with the wheels in a straight ahead position.
2. Raise the vehicle and support the front axle with jack stands.
3. Use paint and mark the center area of tread on both steer axle tires around the complete
outer diameter of the tires.
4. Scribe a line through both steer axle tires in the painted area around the complete outer
diameter of the tires.
5. Raise the vehicle and remove the jack stands.
6. Set the vehicle on the ground.

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27

Alignment & Adjustments

STEERTEK NXT High Capacity Steer Axle System for Autocar® ACX-XPEDITOR™ Vehicles
NOTE

DO NOT measure toe-in with the front axle off the ground. The weight of the vehicle must be on the
front axle when toe-in is measured.
7. Use a trammel bar and measure the distance between the scribe marks at the rear of the
steer axle tires. Record the measurement.
8. Install the trammel bar and measure the distance between the scribe marks at the front of the
steer axle tires. Record the measurement, see Figure 8-15.
FIGURE 8-15

NOTE

When setting up the trammel bar the pointers should be level with the spindles at the front and
rear of the steer axle tires.
9. To calculate the toe setting subtract the front measurement from the rear measurement, the
difference between the two will equal the toe-in / toe-out measurement.
10. If the toe measurement is not within the specifications of 1⁄16" ± 1⁄32" (0.060" ± 0.030"), it will be
necessary to adjust the toe setting. Refer to the following procedure.
a. Loosen the tie rod cross tube clamp bolts and locknuts.
b. Turn the tie rod cross tube until the specified toe-in distance is achieved.
THE THREADED PORTION OF THE TIE ROD END MUST EXTEND PAST THE SLOTS INTO THE TIE ROD
CROSS TUBE, SEE FIGURE 8-16. FAILURE TO DO SO CAN CAUSE COMPONENT TO FAIL CAUSING LOSS
OF VEHICLE CONTROL AND POSSIBLE PERSONAL INJURY OR PROPERTY DAMAGE.

c. Tighten the bolt and locknut on the tie rod cross tube to

68 ± 7 foot pounds torque.

IT IS CRITICAL TO CHECK THE 5⁄ 8" TIE ROD CLAMP BOLT HEAD LOCATION TO VERIFY THE CLAMP
FASTENERS HAVE SUFFICIENT CLEARANCE AWAY FROM THE LOWER SHOCK MOUNT AT FULL WHEEL
CUT. THE FASTENERS MUST NOT CONTACT THE LOWER SHOCK MOUNT. FAILURE TO DO SO CAN
CAUSE ONE OR MORE COMPONENTS TO FAIL CAUSING LOSS OF VEHICLE CONTROL AND POSSIBLE
PERSONAL INJURY OR PROPERTY DAMAGE.

11. Verify the 5⁄8" tie rod clamp bolt head does not contact the lower shock mount at full wheel
cut, see Figure 8-16.
12. Repeat Steps 1-10 until the correct toe setting is achieved.

Alignment & Adjustments

28

17730-297

STEERTEK NXT High Capacity Steer Axle System for Autocar® ACX-XPEDITOR™ Vehicles
FIGURE 8-16

5/8" Tie

Rod Clamp Bolt
It is critical to check the 5/8" tie rod clamp bolt
head location to verify the clamp fasteners have
sufficient clearance away from the lower shock
mount at full wheel cut. The fasteners must not
contact the lower shock mount.

Tie Rod Cross Tube Slots
It is critical to have the threaded
portion of the tie rod end extend past
the slots in the tie rod cross tube.

Threaded Portion
of the Tie Rod End

17730-297

29

5/8" Tie

Rod Clamp Locknut
Tightening Torque 68 ± 7 ft. lbs.

Alignment & Adjustments

STEERTEK NXT High Capacity Steer Axle System for Autocar® ACX-XPEDITOR™ Vehicles

SECTION 9

Component Replacement
FASTENERS
Hendrickson recommends that when servicing the vehicle to replace the 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.

SHOCK ABSORBERS
The shock absorbers are not supplied by Hendrickson, although it is a required component.
Hendrickson is not responsible for components supplied by the vehicle manufacturer. For assistance with inspection, maintenance and rebuild instructions see vehicle manufacturer.

LEAF SPRING AND CLAMP GROUP ASSEMBLY
YOU WILL NEED:
■■

Axle Collar Driver, refer to Special Tools Section of this Publication.

■■

Soft Jaw Vice

DISASSEMBLY
1. Place the vehicle on a level floor.
2. Chock the wheels.
3. Raise the vehicle and support the vehicle with frame stands.
4. Suspend the front axle to remove the load from leaf spring assembly.
5. Remove the tires for greater access.
6. Support the axle with a floor jack.
7. Remove the lower shock absorber mounting fasteners, refer to vehicle manufacturer’s
instructions.
FIGURE 9-1

Leaf Spring with Lower Shock
Absorber Mounting Bracket
and Clamp Group Assembly

1" x 6.5" Axle Collar
Hex Cap Screw

Axle Seat Holes
Axle Seat
Liner

Axle Seat Liner
Holes

Front Axle Collar
Unthreaded

Rear Axle Collar
Threaded
Axle
Axle Holes

Component Replacement

30

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STEERTEK NXT High Capacity Steer Axle System for Autocar® ACX-XPEDITOR™ Vehicles
8. Disconnect the rear shackles.
9. Partially remove the axle collar bolts with a couple of threads engaged, see Figure 9-2.
10. Strike the bolt heads with a hammer to dislodge and drive out the rear collars.
11. Install the collar bushing driver from the rear of the axle, see Figure 9-3.
12. Strike the bushing driver to dislodge and drive out the front axle collars, Figure 9-4, until the
front bushing collars are clear from the axle, see Figure 9-5.
13. Lower the axle until there is enough clearance to remove the leaf spring assembly from the axle.
14. Remove the front spring eye bolt on the side being replaced.
15. Remove the leaf spring and clamp group assembly from the axle.
FIGURE 9-2

FIGURE 9-3

FIGURE 9-4

FIGURE 9-5

FIGURE 9-6

ASSEMBLY
WHEN PLACING THE LEAF SPRING AND CLAMP
GROUP ASSEMBLY IN A VISE IT IS NECESSARY
TO PROTECT THE MACHINED SURFACES FROM
GOUGES OR MARRING BY USING BRASS JAWS
(SOFT JAWS) SEE FIGURE 9-6. FAILURE TO DO
SO CAN CAUSE PREMATURE PART DAMAGE,
DAMAGE TO THE LEAF SPRING AND CLAMP GROUP
ASSEMBLY, LOSS OF WARRANTY, LOSS OF VEHICLE
CONTROL, CAUSING PERSONAL INJURY OR
PROPERTY DAMAGE.

SERVICE HINT

17730-297

It is acceptable to mount the leaf spring and
clamp group components in a soft jaw vise to
facilitate the tightening procedure.

31

1" Hex Bolt

Soft Jaws
Vice

Leaf Spring and Clamp Group Assembly

Component Replacement

STEERTEK NXT High Capacity Steer Axle System for Autocar® ACX-XPEDITOR™ Vehicles
FIGURE 9-7

1. Secure the leaf spring and clamp group
assembly in a suitable holding device,
such as a soft jaw vice, see Figure 9-6.

FIGURE 9-8

2. Ensure the clamp group hex bolts are
tightened to 600 ± 20 foot pounds
torque in the proper pattern to achieve
uniform bolt tension, see Figures 9-7
and 9‑8.
3. Install the new axle seat liner under the
axle seat (liner ear snap to side of axle
seat), see Figure 9-9.
THE WEIGHT OF THE LEAF SPRING AND CLAMP GROUP ASSEMBLY IS APPROXIMATELY 230 POUNDS.
CARE SHOULD BE TAKEN AT REMOVAL AND INSTALLATION TO PREVENT PERSONAL INJURY OR DAMAGE
TO COMPONENTS.

4. Install the new leaf spring and clamp group assembly (approximate weight 230 pounds) on
the axle. Ensure the axle seat liner holes are lined up with the axle seat and axle holes, see
Figures 9-1.
5. Install the non‑threaded collar at the front of the axle and the threaded collars at the rear of
the axle going into the axle seat, axle seat liner and axle. Tap into place with a mallet.
6. Install the new axle collar fasteners with the bolt head located on the front side of the axle.
7. Tighten both sides, left and right of the axle collar bolts in four stages, stage one 100 foot
pounds, stage two 350 foot pounds, stage three 700 foot pounds and the fourth and final
800 ± 20 foot pounds torque, see Figure 9-10.
FIGURE 9-9

FIGURE 9-10

1" Clamp Group Hex Bolt
Tightening Torque at
the Bolt Head
600 ± 20 ft. lbs.
IMPORTANT
Ensure that Clamp
Group Assembly
is properly aligned

8. Raise the axle and the leaf spring clamp
group assembly.
9. Install the axle assembly into the front
hanger and rear shackle assembly as per
vehicle manufacturer’s guidelines.

1" Axle Collar Bolt
Tightening Torque
800 ± 20 ft. lbs.

10. Install the lower shock fasteners and tighten to the vehicle manufacturer’s specifications.
11. Raise the vehicle.
12. Remove the frame supports and load the front axle with the vehicle weight.
13. Install tires per the vehicle manufacturer's specifications.
14. Remove the wheel chocks.

Component Replacement

32

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STEERTEK NXT High Capacity Steer Axle System for Autocar® ACX-XPEDITOR™ Vehicles
CLAMP GROUP COMPONENTS
The clamp group instructions can be used to replace the different components in the clamp
group, such as the leaf spring, axle seat or top pad with jounce stop.

YOU WILL NEED:
■■

Soft Jaw Vice

FIGURE 9-11

DISASSEMBLY
1. Remove the Leaf Spring and Clamp
Group Assembly per instructions in
this Section.
2. Remove and discard the four 1" hex
bolts.

1" x 7" Hex Bolt
Tightening Torque
600 ± 20 ft. lbs.

1" Flat Washer
Top Pad with
Jounce Stop

1" Spherical Washer

3. Remove the top pad with jounce stop.
4. Remove and discard all plastic leaf
spring liners.

Spring Liner

5. Remove the leaf spring assembly.
6. Prior to removal of the leaf spring
spacer, note the location and orientation, see Figure 9-11. Remove the leaf
spring spacer.

Leaf Spring
Spacer

7. Inspect all clamp group components
for any damage, replace as necessary.

ASSEMBLY

Leaf Spring Assembly
with Lower Shock Bracket

Axle Seat
Axle Seat
Liner

1. Install the leaf spring spacer in same
location and orientation as removed, see Figure 9-11.
2. Install the leaf spring onto the spring spacer.
3. Install the new spring liner onto the leaf spring assembly.
4. Install the top pad with jounce stop on top of leaf spring liner.
5. Install the hex bolts into the holes on the top pad and jounce stop, see Figure 9-11, and hand
tighten. DO NOT tighten to torque at this time.
FIGURE 9-12

WHEN PLACING THE LEAF SPRING AND CLAMP
GROUP ASSEMBLY IN A VISE IT IS NECESSARY
TO PROTECT THE MACHINED SURFACES FROM
GOUGES OR MARRING BY USING BRASS JAWS
(SOFT JAWS) SEE FIGURE 9-12. FAILURE TO DO
SO CAN CAUSE PREMATURE PART DAMAGE,
DAMAGE TO THE LEAF SPRING AND CLAMP GROUP
ASSEMBLY, LOSS OF WARRANTY, LOSS OF VEHICLE
CONTROL, CAUSING PERSONAL INJURY OR
PROPERTY DAMAGE.

SERVICE HINT

Soft Jaws

It is acceptable to mount the leaf spring and
clamp group components in a soft jaw vise