see Figure 9-7.

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240 ± 15 foot pounds (325 ± 20 Nm) torque,

Component Replacement

AIRTEK® for Hoist Liftruck T-Series
STEERTEK NXT AXLE ASSEMBLY
The STEERTEK NXT axle clamp group consists of the top pad, ¾" bolts, washers, and nylon locknuts.
FIGURE 9-8

Component Replacement

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AIRTEK® for Hoist Liftruck T-Series
AXLE REMOVAL
Refer to Figure 9-8 when replacing the components of the STEERTEK NXT axle as shown.
DO NOT USE A TORCH ON CLAMP GROUP BOLTS OR ANY OTHER PART OF THE AIRTEK SUSPENSIONS. IF
THE CLAMP GROUP BOLTS WILL NOT COME LOOSE WITH AN IMPACT WRENCH, USE A CUT OFF WHEEL
AND CUT THE SHANK OF THE BOLT. THE USE OF A TORCH CAN CAUSE DAMAGE TO CERTAIN AIRTEK
COMPONENTS THAT CAN RESULT IN THE LOSS OF VEHICLE CONTROL AND POSSIBLE PERSONAL
INJURY OR PROPERTY DAMAGE.

1. Place the vehicle on level floor.
2. 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.

3. See additional Air Spring Cautions and Warnings in the Important Safety Notice Section of this
publication prior to deflating or inflating the air system.
AIR SPRING ASSEMBLIES MUST BE DEFLATED PRIOR TO LOOSENING ANY CLAMP GROUP HARDWARE.
UNRESTRICTED AIR SPRING ASSEMBLIES CAN VIOLENTLY SHIFT. DO NOT INFLATE AIR SPRING
ASSEMBLIES WHEN THEY ARE UNRESTRICTED. AIR SPRING ASSEMBLIES MUST BE RESTRICTED
BY SUSPENSION OR OTHER ADEQUATE STRUCTURE. DO NOT INFLATE BEYOND PRESSURES
RECOMMENDED BY AIR SPRING MANUFACTURER, CONTACT HENDRICKSON TECHNICAL SERVICES
FOR DETAILS. IMPROPER USE OR OVER INFLATION MAY CAUSE AIR SPRING ASSEMBLIES TO BURST,
CAUSING PROPERTY DAMAGE AND / OR SEVERE PERSONAL INJURY.

4. Exhaust the air from the air system by disconnecting the height control valve linkage(s) at the
rubber grommet(s) and allowing the lever to drop. Lower the height control valve lever arm.
This will exhaust air from the system.
5. Raise the vehicle.
6. Support the vehicle with frame stands.
THE INTEGRATED AXLE SPRING SEATS ON THE STEERTEK NXT AXLE ARE NON-SERVICEABLE. DO
NOT REMOVE, MODIFY OR REPLACE INTEGRATED FASTENERS, DOING SO CAN CAUSE STRUCTURAL
DAMAGE AND RESULT IN LOSS OF VEHICLE CONTROL, PROPERTY DAMAGE, SEVERE PERSONAL INJURY,
OR DEATH AND VOID ANY APPLICABLE WARRANTY.

7. Suspend the front axle with the shocks attached.
8. Remove the front wheels, hubs, brake shoes, ABS sensors, and backing plate assembly.
9. Disconnect the drag link from the steering arm.
IF THE AIR SPRING IS TO BE RE-INSTALLED; CARE MUST BE TAKEN TO REMOVE DIRT AND DEBRIS
FROM THE PUSH-TO-CONNECT FITTING. FAILURE TO DO SO COULD RESULT IN THE PUSH-TO-CONNECT
FITTING FAILING TO SEAL WITH THE AIR LINE. INSPECT LOCK-TABS FOR DAMAGE OR CRACKS PRIOR TO
RE-INSTALLATION.

10. Unseat both of the air springs at the axle top pad.
11. Support the axle with a floor jack.
THE REPAIR OR RECONDITIONING OF SUSPENSION OR AXLE COMPONENTS IS NOT ALLOWED.
ANY SUSPENSION OR AXLE COMPONENTS FOUND TO BE DAMAGED OR OUT OF SPECIFICATIONS
MUST BE REPLACED. ALL MAJOR HENDRICKSON COMPONENTS ARE HEAT TREATED AND TEMPERED.
AIRTEK COMPONENTS CANNOT BE BENT, WELDED, HEATED, OR REPAIRED WITHOUT REDUCING THE
STRENGTH OR LIFE OF THE COMPONENT. FAILURE TO FOLLOW THESE GUIDELINES CAN CAUSE LOSS
OF VEHICLE CONTROL, POSSIBLE PERSONAL INJURY, DEATH, OR PROPERTY DAMAGE AND WILL VOID
APPLICABLE WARRANTIES.

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Component Replacement

AIRTEK® for Hoist Liftruck T-Series
SERVICE HINT

If a clamp group nut fails to come off bolt, cut half way through the bolt with an abrasive cut off
wheel, taking care not to contact axle beam or other components. Using an impact wrench, spin
the locknut to fracture the bolt and remove.
12. Remove the ¾" clamp group fasteners and discard.
13. Lower the axle and remove from the vehicle.

STEERTEK NXT AXLE (REMOVED FROM CHASSIS)
DISASSEMBLY
1. Remove the tie rod assembly. See Tie Rod Ends and Cross Tube in this section.
REMOVAL OF THE CAP SCREWS WILL ALLOW THE STEERING KNUCKLE TO SEPARATE FROM THE AXLE.
THE STEERING KNUCKLE MUST BE SUPPORTED BEFORE REMOVAL OF THESE TWO (2) CAP SCREWS.
FAILURE TO DO SO CAN CAUSE COMPONENT DAMAGE OR PERSONAL INJURY.

2. Remove the two (2), 5⁄8" socket head cap screws from the steering knuckle assembly.
3. Remove the steering knuckle and thrust bearing.
4. After complete removal of the one side, repeat Steps 1 through 3 for the opposite side of
the axle.
5. Inspect the steering kingpin bushings for excessive wear. If worn, replace the kingpin bushings
and seals. See Kingpin Bushing replacement instructions in this section.
FIGURE 9-9

INSTALLATION
1. Place the new axle on the floor jack and position the axle under the vehicle, see Figure 9-9.
2. Raise the axle into position. Care must be taken at this point to ensure that the center bolt of
front leaf spring assembly is aligned properly with the axle spring seat, see Figure 9-9.

Component Replacement

46

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AIRTEK® for Hoist Liftruck T-Series
FIGURE 9-10

3. Install the top pad with the directional identification
facing correctly on the vehicle, See Figure 9-10.
4. Install the new ¾" clamp group fasteners. Snug the
bolts, DO NOT tighten to the specified torque at this
time.
5. Ensure that the clamp groups are properly aligned
and the bolts are seated in the top pad, and the top
pad is centered on the axle spring seat, see Figures
9-11 and 9-12.
FIGURE 9-11

FIGURE 9-12

6. See additional Air Spring Cautions and Warnings in the Important Safety Notice Section of this
publication prior to inflating or deflating the suspension system.
7. Engage the air springs into the top pad. Install new lower air spring mounting fasteners and
tighten to 30 ± 5 foot pounds (41 ± 7 Nm) torque.
8. Install the lower shock absorber connection (if removed). Install the lower shock fasteners and
tighten to 240 ± 15 foot pounds (325 ± 20 Nm) torque.
9. Install the steering knuckles as per the Steering Knuckle assembly instructions in this section.
10. Install the tie rod assembly as per the Tie Rod End and Cross Tube assembly instructions in
this section.
11. Install the 7⁄8" hardened washers on the Ackermann arm and the castle nuts. Tighten the castle
nuts to 185 foot pounds (251 Nm), then rotate until the first castle slot lines up with the
cotter pin bore in the tie rod end. DO NOT back off the nut for cotter pin installation.
12. Install the tie rod end cotter pins.
13. Connect the drag link in the steering arms.
14. Install the castle nut to install the steering arm. Tighten the castle nut to 185 foot pounds,
(251 Nm) then rotate until the first castle slot lines up with the cotter pin bore in the drag link.
DO NOT back off nut for cotter pin installation.
15. Install the drag link cotter pin.
16. Install the brake backing plate assemblies.
17. Install the brakes, hubs, and wheels as per manufacturer’s guidelines.
18. Fill the hubs with the proper lubricant (see manufacturer’s guidelines for recommended lubrication specifications).
19. Grease the front steering components as per lubrication guidelines in the Preventive
Maintenance Section of this publication.
20. Raise the vehicle and remove the frame stands.
21. Lower the vehicle.
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AIRTEK® for Hoist Liftruck T-Series
22. Reconnect the height control valve and air up the system.

FIGURE 9-13

23. Tighten the ¾" clamp group locknuts evenly in 50 foot pounds increments
to 300 ± 10 foot pounds (407 ± 14 Nm) torque in the proper sequence
to achieve uniform bolt tension, see Figure 9-13.
24. Adjust ride height per instructions in the Alignment & Adjustments Section
of this publication.
25. Remove the wheel chocks.

STEERING KNUCKLE
DISASSEMBLY
The steering knuckle disassembly and assembly procedure includes the Kingpin Preparation and
Measurement and Kingpin Bushing Removal process.
FIGURE 9-14

1. Place the vehicle on level floor.
2. Chock the wheels.
3. Raise the frame.
4. Support the vehicle with frame stands.
5. Remove the wheel and hub assembly.
6. Remove the brake components from steering
knuckle.
7. Remove the tie rod assembly.
SERVICE HINT

Lightly tap the side of the Ackermann arm with a mallet to separate the tie rod end from the
Ackermann arm, see Figure 9-14.
8. Remove the drag link from the knuckle if necessary.
FIGURE 9-15

REMOVAL OF THE CAP SCREWS WILL
A L LO W T H E S T E E R I N G K N U C K L E
T O S E PA R AT E F R O M T H E A X L E .
THE STEERING KNUCKLE MUST BE
SUPPORTED BEFORE REMOVAL OF
THESE TWO (2) CAP SCREWS. FAILURE
TO DO SO CAN CAUSE COMPONENT
DAMAGE OR PERSONAL INJURY.

9. Remove the two (2) socket head
cap screws that connect upper
kingpin connection to the steering
knuckle, see Figure 9-15.
10. Remove the lower steering knuckle
from the kingpin by sliding it down the kingpin.
11. Remove the upper steering knuckle by sliding it up off the kingpin.

Component Replacement

48

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AIRTEK® for Hoist Liftruck T-Series
KINGPIN PREPARATION AND MEASUREMENT
■■

Cleaning Ground and Polished Parts
●●

●●

Use a cleaning solvent to clean ground or polished parts and surfaces. DO NOT USE
GASOLINE.
DO NOT clean ground or polished parts in a hot solution tank or with water, steam, or
alkaline solutions. These solutions will cause corrosion of the parts.

DRYING THE CLEANED PARTS
■■

Parts must be dried immediately after cleaning. Dry the parts with clean paper towels, clean
rags, or compressed air. DO NOT dry bearings by spinning with compressed air. Damage to
the bearings will result.

PREVENTING CORROSION ON CLEANED PARTS
■■

Apply a light coating of oil to all cleaned and dried parts that are going to be reused. DO NOT
apply oil to the brake lining or the brake drums. If parts are to be stored, apply an effective rust
inhibitor to all surfaces.

TO HELP PREVENT SERIOUS EYE INJURY, ALWAYS WEAR PROPER EYE PROTECTION WHEN YOU
PERFORM VEHICLE MAINTENANCE OR SERVICE.
SOLVENT CLEANERS CAN BE FLAMMABLE, POISONOUS AND CAUSE BURNS. TO HELP AVOID SERIOUS
PERSONAL INJURY, CAREFULLY FOLLOW THE MANUFACTURER’S PRODUCT INSTRUCTIONS AND
GUIDELINES AND THE FOLLOWING PROCEDURES:
■■

WEAR PROPER EYE PROTECTION

■■

WEAR CLOTHING THAT PROTECTS YOUR SKIN

■■

WORK IN A WELL VENTILATED AREA

■■

DO NOT USE GASOLINE, SOLVENTS OR OTHER MATERIALS THAT CONTAIN GASOLINE THAT CAN
EXPLODE

■■

HOT SOLUTION TANKS OR ALKALINE SOLUTIONS MUST BE USED CORRECTLY. FOLLOW THE
MANUFACTURER’S RECOMMENDED INSTRUCTIONS AND GUIDELINES CAREFULLY TO HELP
PREVENT PERSONAL ACCIDENT OR INJURY.

DO NOT USE HOT SOLUTION TANKS OR WATER AND ALKALINE SOLUTIONS TO CLEAN GROUND OR
POLISHED PARTS. DAMAGE TO THE PARTS WILL RESULT.
THE STEERTEK NXT HAS A UNIQUE AXLE. THE KINGPIN IS CRYOGENICALLY INSTALLED IN THE AXLE.
THE KINGPIN IS A NON-REPLACEABLE COMPONENT OF THE AXLE ASSEMBLY. DO NOT TRY TO REMOVE
THE KINGPIN. DOING SO WILL DAMAGE THE AXLE AND MAY CAUSE LOSS OF VEHICLE CONTROL,
PERSONAL INJURY OR PROPERTY DAMAGE. IF THE KINGPIN SHOWS SIGNS OF MOVEMENT, CONTACT
HENDRICKSON PRODUCT ENGINEERING - TECH SERVICES.

1. Prepare and polish the kingpin by removing all grease and excess debris using a fine grit
(220 grit or higher) emery cloth and parts solvent, see Figures 9-16 through 9-19.
2. Inspect the kingpin for wear or damage. Use a micrometer and measure the upper and
lower kingpin in two locations. Positions must be 90º opposed from each other. If the kingpin has less than 1.802" diameter, replacement of the axle is necessary, see Figures 9-20
through 9-23. Kingpin minimum dimension is 1.802".

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Component Replacement

AIRTEK® for Hoist Liftruck T-Series

Component Replacement

FIGURE 9-16

FIGURE 9-17

FIGURE 9-18

FIGURE 9-19

FIGURE 9-20

FIGURE 9-21

FIGURE 9-22

FIGURE 9-23

50

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AIRTEK® for Hoist Liftruck T-Series
KINGPIN BUSHING
You will need:
■■

A hydraulic shop press with a minimum forcing capacity of 2.5 tons (or an arbor press) or
optional method - use hand tools.

■■

Adjustable Straight Flute Reamer with a cutting diameter must facilitate a range of
1.802" - 1.812"

Refer to the Special Tools Section of this publication for the following shop made tools:
■■

Kingpin Bushing Driver Tool

■■

Kingpin Bushing Receiving Tool (for shop press method)

■■

Kingpin Handle, Bushing Driver Installer / Remover and Seal Driver Installer Tool

BEFORE APPLYING HYDRAULIC PRESSURE TO ANY TOOLING SET-UP, ALWAYS CHECK TO ENSURE THE
PRESS PLATE, ADAPTERS, AND COMPONENTS BEING WORKED ON ARE POSITIONED PROPERLY, I.E.
“IN LINE” WITH THE RAM OF THE PRESS. IMPROPER POSITIONING CAN CAUSE PERSONAL INJURY OR
COMPONENT DAMAGE.
PRIOR TO APPLYING HYDRAULIC PRESSURE TO REMOVE OR INSTALL THE KINGPIN BUSHING, SUPPORT
THE LOWER STEERING KNUCKLE AS SHOWN IN FIGURES 9-27 AND 9-28. IMPROPER SUPPORT TO THE
STEERING KNUCKLES CAN CAUSE COMPONENT DAMAGE.

REMOVAL
1. Remove the threaded grease cap and grease zerk.
NOTE

If a shop press is not available to remove and install the kingpin bushings, an acceptable optional
method is to use a hammer along with the shop made tools (Kingpin Bushing Drivers and Seal
Driver Tools) on a work bench.
2. With the machined side of the steering knuckle face down (axle side down), ensure the steering
knuckle assembly is squarely supported on the Bushing Receiving Tool prior to applying hydraulic pressure to press out the kingpin bushings, see Figures 9-24 and 9-26.

NOTE

To remove the kingpin bushing, always drive the bushing from the non-machined side of the steering knuckle.
3. Use the Kingpin Handle and Bushing Driver Installer / Remover Tool (see Special Tools Section
of this publication) to drive the kingpin bushing and kingpin seal out of the steering knuckle,
see Figures 9-24 through 9-26.
4. Clean the parts and inspect for reassembly.

FIGURE 9-24

17730-313

FIGURE 9-25

FIGURE 9-26

51

Component Replacement

AIRTEK® for Hoist Liftruck T-Series
STEERING KNUCKLE BORE MEASUREMENT
Complete the following steering knuckle bore inspection and the measurement instructions prior
to installing the kingpin bushing.
1. Measure the upper knuckle bore inside diameter at two locations. Always use an inside
micrometer or a telescoping gauge when taking a knuckle bore measurement. Some outof-roundness at the top and bottom of the bore edges is acceptable. Steering knuckle bore
diameter is 1.938" ± 0.003".
2. Measure the upper and lower bore in two positions and at two locations.The two positions must
be 90º opposed from each other, see Figures 9-27 through 9-29 If the average measurement is
more than the knuckle bore maximum diameter specification, replace the knuckle.
FIGURE 9-27

FIGURE 9-28

FIGURE 9-29

INSTALLATION
BEFORE APPLYING HYDRAULIC PRESSURE TO ANY TOOLING SET-UP, ALWAYS CHECK TO ENSURE THE
PRESS PLATE, ADAPTERS, AND COMPONENTS BEING WORKED ON ARE POSITIONED PROPERLY, I.E.
“IN LINE” WITH THE RAM OF THE PRESS. IMPROPER POSITIONING CAN CAUSE PERSONAL INJURY OR
COMPONENT DAMAGE.

NOTE

If a shop press is not available to remove and install the kingpin bushings, an acceptable optional
method is to use a hammer along with the shop made tools (Kingpin Bushing Drivers and Seal
Driver Tools) on a work bench.
1. With the machined side of the steering knuckle face up (axle side up), ensure that each part
of the steering knuckle assembly is squarely supported before applying hydraulic pressure to
press in the kingpin bushing, see Figure 9-30.

NOTE

To install the kingpin bushing, always drive the bushing from the machined side of the steering
knuckle.
2. Use the Kingpin Bushing Driver Tool (see tool specifications in the Special Tools Section of
this publication) to drive the bushing until its flush with the machined surface of the steering
knuckle.
FIGURE 9-30

Component Replacement

FIGURE 9-31

52

FIGURE 9-32

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AIRTEK® for Hoist Liftruck T-Series
3. Use the Kingpin Handle and Bushing Driver Installer / Remover Tool to sink the kingpin bushing
to just below the seal bore, see Figures 9-30 to 9-32.
4. Following this procedure it is necessary to ream the kingpin bushings to fit the kingpins, see
Kingpin Bushing Reaming Instructions in this section.

KINGPIN BUSHING REAMING
REAM THE KINGPIN BUSHINGS WITH AN ADJUSTABLE STRAIGHT FLUTE REAMER. DO NOT HONE OR
BURNISH THE KINGPIN BUSHINGS. HONING OR BURNISHING WILL DAMAGE THE BUSHINGS AND VOID
ANY APPLICABLE WARRANTY.
WHEN INSTALLING STEERING KNUCKLE COMPONENTS IN A VISE IT IS NECESSARY TO PROTECT
THE MACHINED SURFACES FROM GOUGES OR MARRING BY USING BRASS JAWS (SOFT JAWS).
FAILURE TO DO SO CAN CAUSE PREMATURE PART DAMAGE, DAMAGE TO THE STEERING KNUCKLE
COMPONENTS, LOSS OF WARRANTY, LOSS OF VEHICLE CONTROL, CAUSING PERSONAL INJURY OR
PROPERTY DAMAGE.

1. Install the lower steering knuckle assembly in a vise with brass jaws (soft jaws).
SERVICE HINT

It is acceptable to mount the knuckle components in a vise either vertically or horizontally when
performing the reaming procedure.
2. Install the reamer into the lower steering knuckle until the blades touch the kingpin bushing.
3. Rotate the reamer with light downward pressure. Rotate the reamer smoothly. DO NOT apply
too much pressure, see Figures 9-33 and 9-34.
4. Slide the reamer out of the lower steering knuckle assembly. If it is necessary to remove the
reamer from the top, rotate the reamer opposite of cutting rotation.
5. Clean and remove all kingpin bushing material from the knuckle assembly. Take special attention to remove material from the grease channels and dimples.
6. Clean the 5⁄8" brake backing plate bolts with a wire wheel and run a tap through the threads
of the upper kingpin connection / steering arm and then flush out with brake cleaner and dry
with compressed air.
PRIOR TO INSTALLATION ENSURE THAT ALL RESIDUAL LOCTITE MATERIAL IS REMOVED FROM THE
MOUNTING BOLTS AND THE THREAD BORES IN THE UPPER KINGPIN CONNECTION OR STEERING
ARM, AND NEW LOCTITE 277 OR EQUIVALENT IS APPLIED TO HELP ENSURE THAT THE BOLTS SUSTAIN
THE PROPER TORQUE REQUIREMENT. FAILURE TO DO SO CAN CAUSE LOSS OF VEHICLE CONTROL
RESULTING IN PERSONAL INJURY OR PROPERTY DAMAGE.

NOTE

The Hendrickson Genuine part, socket head cap screw comes with a pre-applied Loctite
compound.
FIGURE 9-33

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FIGURE 9-34

53

Component Replacement

AIRTEK® for Hoist Liftruck T-Series
7. Install the steering arm and upper kingpin connection on the kingpin.
8. Check for the proper fit by rotating the knuckle assembly back and forth to verify there is no
binding on the kingpin, see Figures 9-35 and 9-36.
FIGURE 9-35

FIGURE 9-36

9. If the bushing is too tight repeat Steps
1 through 8 until the proper clearance
is achieved.
NOTE

Bushing size is to be 0.001" larger than
the kingpin size.

KINGPIN SEAL INSTALLATION
1. Place the steering knuckle assembly
in a vise with brass jaws (soft jaws)
or place on a suitable workbench.
The steering knuckle will have the
machined surface facing up (axle
side up).
2. Lay the kingpin seal into the bore of the steering knuckle. The seal lip should face outward or
toward the axle, see Figure 9-37.
3. Use the Kingpin Bushing Driver Tool (see Special Tool Section) and press the kingpin seal
firmly into the steering knuckle assembly.
4. Use the Kingpin Handle and Seal Driver Installer Tool (see Special Tools Section of this publication) to sink the kingpin seal until it bottoms out in the kingpin bore, see Figure 9-38.
FIGURE 9-37

Component Replacement

FIGURE 9-38

54

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AIRTEK® for Hoist Liftruck T-Series
STEERING KNUCKLE ASSEMBLY
NOTE

After replacement of the kingpin bushings it is necessary to re‑assemble the steering knuckle
assemblies. The STEERTEK NXT axle is equipped with two (2) different thrust bearings installed.
The composite thrust bearing is installed on the left side of the axle. The roller bearing is
installed on the right side of the axle, see Figure 9-39. DO NOT substitute aftermarket components when servicing.
FIGURE 9-39

1. Install the thrust bearing on the
lower kingpin with the seal facing
up toward axle (the black seal will
designate the top side), see Figure
9-39.
2. Pack the bushing dimples on the
upper and lower steering knuckles
with multi purpose Lithium based
grease (NLGI Grade 2) before
installation.

Black Seal