STEERTEK NXT High Capacity Steer Axle System for Fire and Rescue Vehicles
6. 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 9-18.
FIGURE 9-18

7. Install the steering knuckles, refer to the Steering
Knuckle Assembly instructions in this ­section.
8. Install the tie rod assembly in the tie rod arms.
9. Install the 7⁄8" hardened washers on the tie rod
arm and the castle nuts. Tighten the castle nuts to
185 foot pounds, then rotate until the first castle slot lines up with the cotter pin bore in the tie
rod end. DO NOT back off nut for cotter pin
installation.
10. Install the tie rod end cotter pin.
11. Connect the drag link in the steering arm.
12. Install the castle nut on the drag link taper stud.
Tighten the c­ astle nut to 185 foot pounds, 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.
13. Install the drag link cotter pin.
14. Install the brake backing plate assemblies and ABS sensor and torque all fasteners per manufacturer’s specifications.
15. Install the brakes, hubs, and wheels per the vehicle manufacturer’s guidelines.
16. Raise the vehicle and remove the frame supports.
17. Lower the vehicle and load the front axle with the truck’s weight. Remove the floor jack.
18. Remove the wheel chocks.
19. Fill the hubs with the proper lubricant, (see manufacturer’s guidelines for recommended
lubrication), if required.
20. Grease the front steering components as per lubrication guidelines in the Preventive
Maintenance Section of this publication.

STEERING KNUCKLE

FIGURE 9-19

DISASSEMBLY
1. Place the vehicle on level floor.
2. Chock the wheels.
3. Support the vehicle with jack stands on the axle.
4. Remove the wheel and hub assembly.
5. Remove the brake components from steering knuckle.
SERVICE HINT

Lightly tap the side of the tie rod arm with a mallet to separate the tie rod end from the tie rod arm, see Figure 9-19.

Lightly tap the side
of tie rod arm to
loosen the tie rod end

6. Disconnect the tie rod assembly from the tie rod
arms, see Figure 9-19.
7. Remove the tie rod assembly.

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STEERTEK NXT High Capacity Steer Axle System for Fire and Rescue Vehicles
STEERING ARM DISASSEMBLY

FIGURE 9-20

1. Remove the two steering-arm-toknuckle hex bolts from the knuckle
assembly. Figure 9-20.
2. Remove the steering arm from the
knuckle. If necessary, use a leather or
plastic mallet to tap the outside of the
arm and separate the arm from the
knuckle.
3. Remove the steering arm.
4. Inspect the steering arm for cracks or damage, replace as necessary.

TIE ROD ARM DISASSEMBLY

FIGURE 9-21

S U P P O R T T H E T I E R O D A S S E M B LY D U R I N G
MAINTENANCE AND SERVICE TO PREVENT SERIOUS
PERSONAL INJURY AND DAMAGE TO COMPONENTS.
DO NOT HEAT THE TIE ROD ARM TO REMOVE THE TIE
ROD ASSEMBLY. HEATING THE TIE ROD ARM WILL
SOFTEN PARTS AND DAMAGE TO COMPONENTS WILL
RESULT.

1. Remove and discard tie rod arm 7⁄8" fasteners.
2. Remove the tie rod arms, see Figure 9-21.

GREASE CAP, DRAW KEY AND KINGPIN DISASSEMBLY
You will need:
■■

Brass drift and hammer

■■

Heavy-duty King Pin Press that can generate 46,000 pounds of force and will accommodate
kingpins size of 2" to 2 5⁄32"
FIGURE 9-22

1. Remove the top grease cap.
2. Remove the draw keys.
a. Loosen the threaded draw key locknut until the top of the locknut is
even with the end of the draw key,
see Figure 9-22.
b. Use a brass drift and a hammer to hit
the end of the draw key.
c. Remove the nut from the draw key. Remove the draw key from the knuckle.
3. If you are not replacing the bushings, use the following procedure to prevent damaging the
bushings during kingpin removal.
a. Use a brass drift and a hammer to remove the kingpins from the knuckle. Figure 9-23.
b. Remove any flaring on the drift that touches the bushings.
c. Wrap tape to a thickness of 1⁄16" (1.5 mm) onto the end of the drift.
DO NOT HEAT THE AXLE TO REMOVE THE KINGPIN. HEATING THE AXLE WILL DAMAGE THE AXLE AND
STEERING KNUCKLE COMPONENTS. FAILURE TO DO SO CAN CAUSE, LOSS OF WARRANTY, LOSS OF
VEHICLE CONTROL CAUSING PERSONAL INJURY OR PROPERTY DAMAGE.
Component Replacement

40

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STEERTEK NXT High Capacity Steer Axle System for Fire and Rescue Vehicles
4. If the kingpin is difficult to remove, use a hydraulic kingpin press to remove the kingpin.
FIGURE 9-23

FIGURE 9-24

5. Remove the knuckle from the axle beam.
WEAR GLOVES WHEN YOU REMOVE OR INSTALL SHIMS. SHIMS HAVE SHARP EDGES THAT CAN CAUSE
SERIOUS PERSONAL INJURY.

6. While wearing gloves, remove the shims, the thrust bearing and the seal from the beam and /
or steering knuckle. Figure 9-24.
7. Inspect the parts, refer to the Preventive Maintenance Section of this publication.

KINGPIN BUSHING
You will need:
■■

Impact wrench

■■

Adjustable straight flute reamer with a cutting diameter must facilitate a range of 2.0" to 2.01"

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

FIGURE 9-25

17730-311

■■

Kingpin Bushing / Seal Driver

■■

Kingpin Bushing and Seal Installer / Remover Tools
FIGURE 9-26

FIGURE 9-27

41

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STEERTEK NXT High Capacity Steer Axle System for Fire and Rescue Vehicles
REMOVAL
1. Place the steering knuckle on a workbench squarely supported.
2. Place the kingpin bushing and seal installer / remover tools in the steering knuckle / kingpin
bore, see Figure 9-25.
3. Use a hammer and drive out the kingpin bushing, see Figure 9-26.
4. Rotate the knuckle over and repeat Steps 1-3 to remove the other kingpin bushing.
5. Clean the knuckle kingpin bores with a rotary wire wheel and inspect for reassembly, see
Figure 9-27.

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 9-28 through 9-30. If the average measurement is more than the knuckle bore maximum diameter specification, replace the knuckle.
FIGURE 9-28

FIGURE 9-29

FIGURE 9-30

INSTALLATION
1. Install kingpin bushings from the axle side of the steering knuckle.
2. Place the new kingpin bushing into the steering knuckle bore so the seam DOES NOT align
with the grease channel, see Figures 9-31 and 9-32.
FIGURE 9-31

Component Replacement

NOTE the
location of the
grease channel

42

FIGURE 9-32
DO NOT place the Kingpin INCORRECT Kingpin
Bushing Seam in line bushing orientation
with the grease channel

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STEERTEK NXT High Capacity Steer Axle System for Fire and Rescue Vehicles
3. Use the kingpin bushing driver to install the kingpin bushing into the steering knuckle bore,
see Figure 9-33. Continue installation until the kingpin bushing is flush with the machined
surface of the steering knuckle.
4. Remove the kingpin bushing / seal driver.
5. Install the kingpin bushing and seal installer / remover tools.
6. Continue driving the kingpin bushing into the steering knuckle until it is flush with the bottom
of kingpin seal bore, see Figures 9-34 and 9-35.
7. Repeat steps for the remaining kingpin bushing.
8. Ream the bushings, see Kingpin Bushing Reaming in this section.
FIGURE 9-33

FIGURE 9-34

FIGURE 9-35

Kingpin Bushing
and Seal Installer /
Remover Tools

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

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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.

1. Inspect the kingpin for wear or damage. Use a micrometer and measure the kingpin. If the
kingpin has less than 2.0" diameter, replacement is necessary, see Figure 9-36.
2. Set up the adjustable straight flute reamer to match kingpin dimension, see Figure 9-37. The
dimension of cutting diameter must facilitate a range of 2.0" to 2.001".
Kingpin minimum dimension is 2.0"
FIGURE 9-36

FIGURE 9-37

Kingpin minimum
dimension is 2.0"

The cutting diameter
dimension must facilitate
a range of 2.0" to 2.001"

KINGPIN BUSHING REAMING
WHEN INSTALLING STEERING KNUCKLE COMPONENTS IN A VISE IT IS NECESSARY TO PROTECT
THE MACHINED SURFACES FROM GOUGES OR MARRING BY USING BRASS JAWS, SEE FIGURE 9-38.
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.
PRIOR TO INSTALLATION ENSURE THAT ALL RESIDUAL LOCTITE® MATERIAL IS REMOVED FROM THE
MOUNTING BOLTS AND THE THREAD BORES IN THE UPPER STEERING KNUCKLES, 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

Bushing size is to be 0.001" larger than the kingpin size.
1. Place the knuckle in a vise with brass jaws (soft jaws), see Figure 9-38.
2. Install the pilot in the lower kingpin bore.

Component Replacement

44

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STEERTEK NXT High Capacity Steer Axle System for Fire and Rescue Vehicles
FIGURE 9-38
Brass Jaws
(Soft Jaws)

REAM THE KINGPIN BUSHINGS WITH
AN ADJUSTABLE STRAIGHT FLUTE
REAMER. (SEE SPECIAL TOOLS SECTION
OF THIS PUBLICATION) DO NOT HONE
OR BURNISH THE KINGPIN BUSHINGS.
HONING OR BURNISHING WILL
DAMAGE THE BUSHINGS AND VOID ANY
APPLICABLE WARRANTY.

Vice

3. Install the adjustable straight flute
reamer into the pilot.
4. Slide the adjustable straight flute
reamer into the upper bushing and into the pilot until the reamer blades touch the bushing.
5. Rotate the adjustable straight flute reamer with a light DOWNWARD pressure. DO NOT apply
too much force. Rotate the reamer smoothly, see Figure 9-39.
FIGURE 9-39

FIGURE 9-40

Adjustable Straight
Flute Reamer Tool
Adjustable Straight
Flute Reamer Tool

Brass Jaws
(Soft Jaws)

Vice

Brass Jaws
(Soft Jaws)

Vice

6. Turn the knuckle over in the vise and repeat Steps 2-5 for the other kingpin bushing, see
Figures 9-39 and 9-40.
SERVICE HINT

If the adjustable straight flute reamer must be removed through the bushing. Rotate the tool in the
opposite cutting direction.
7. Clean all material from the bushings.
8. Lightly lubricate the new the kingpin with penetrating oil and slide into the steering knuckle
bore to ensure the kingpin fits properly into the kingpin bushings.

KINGPIN SEAL INSTALLATION
1. Place the steering knuckle assembly on a suitable workbench.
2. Lay the kingpin seal into the bore of the steering knuckle. Ensure the lip of the kingpin seal
faces toward the axle, see Figure 9-41.
3. Use the kingpin bushing / seal driver tool and drive the kingpin seal firmly into the steering
knuckle assembly with a hammer.
4. Use a kingpin bushing and seal installer / remover tools with a hammer until it bottoms out in
the kingpin bore, see Figure 9‑42.

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STEERTEK NXT High Capacity Steer Axle System for Fire and Rescue Vehicles
FIGURE 9-41
Ensure the lip of the
Kingpin Seal is facing
towards the axle.

FIGURE 9-42
Kingpin seal
bottoms out in the
kingpin bore

STEERING KNUCKLE INSTALLATION
FIGURE 9-43

1. Clean the kingpin bores
of the axle beam.
2. Install the thrust bearing
assembly on the inner
steering knuckle. The
seal must face UPWARD
toward the beam. The
top inner diameter will
c o n ta c t t h e b o t to m
of the axle beam, see
Figures 9-43 and 9-44.

Kingpin Seal MUST face
upward towards the axle

Top View

The top inner
diameter contacts
the bottom of
the axle beam

Bottom View

FIGURE 9-44

WEAR GLOVES WHEN YOU INSTALL THE SHIMS. SHIMS
HAVE SHARP EDGES THAT CAN CAUSE SERIOUS
PERSONAL INJURY.

Upper Drawkey

3. Place the knuckle onto the axle beam, see
Figure 9-44.
4. Place a pry bar between the steering arm boss and
the axle beam. Lift the knuckle and slide the shim
pack between the top of the beam and the steering
knuckle, see Figure 9-45.

Thrust Bearing
and Seal
Assembly

5. Align all the steering knuckle components within the
kingpin bore. If the bores are not aligned, the components will be damaged during kingpin installation.
6. Remove the pry bar.
7. Apply the multi-purpose grease onto the bottom
half of the kingpin prior to kingpin installation onto
the steering knuckle.

Lower
Drawkey
Knuckle Assembly

VERIFY THAT THE DRAW KEY IS INSTALLED COMPLETELY
OR THE LOCKNUT IS TIGHTENED TO 35 ± 5 FOOT POUNDS TORQUE. IF NOT INSTALLED CORRECTLY,
THE KINGPIN AND THE AXLE BEAM WILL BE DAMAGED.

8. Install the kingpin into the top of the knuckle and through the area where the shims are
located, see Figures 9-46 and 9-47. DO NOT force the kingpin through the upper kingpin
bushing. Ensure the word TOP is facing up, see Figure 9-48.

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STEERTEK NXT High Capacity Steer Axle System for Fire and Rescue Vehicles
FIGURE 9-45

FIGURE 9-46

FIGURE 9-47

Kingpin
Shim

Align
Kingpin

Upper
Drawkey

Kingpin
Installation

Axle

Lower Drawkey
FIGURE 9-48

9. Rotate the kingpin and slide in until the two draw
key slots align with the axle draw key bores, see
Figure 9-49 and 9-50.

Verify the word
TOP is stamped
on the kingpin.

10. If required, use a hammer and a brass drift to apply
direct force to the kingpin for seating into the lower
steering knuckle bore, see Figure 9-49.
11. Seat the upper draw key into the front of the axle
beam, see Figure 9-50.
12. Seat the lower draw key into the back of the axle
beam by striking it with a hammer and drift, see
Figure 9-49. The draw keys must align with the slots
of the kingpin.
13. Install draw key locknuts, Snug, DO NOT tighten torque until after the steering knuckle vertical
end play procedure is completed.
FIGURE 9-49
LOWER DRAW KEY

FIGURE 9-50
UPPER DRAW KEY

4¾" Draw Key
Part No. 75925-002
Back of the Axle Beam

3 3/8" Draw Key
Part No. 75925-001
Front of the Axle Beam

MEASURE STEERING KNUCKLE VERTICAL END PLAY
1. Turn the knuckle to the straight-ahead position.
2. Attach a dial indicator to the axle. Place the tip onto the top of the steering knuckle.
3. Set the dial indicator to zero, see Figure 9-51.

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STEERTEK NXT High Capacity Steer Axle System for Fire and Rescue Vehicles
FIGURE 9-51