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

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

Steering Knuckle 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 Ackermann 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

Knuckle Assembly

1. Remove the two steering-arm-toknuckle hex bolts from the knuckle
assembly. Figure 9-20.

1" Hex Bolt

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.

Steering Arm

3. Remove the steering arm.
4. Inspect the steering arm for cracks or damage, replace as necessary.

Tie Rod Arm Disassembly
Figure 9-21

Support the tie rod assembly during
maintenance and service to prevent
serious personal injury and damage
to components.

Knuckle
Assembly
Castle Nut
Cotter Pin

Do not heat the arm to remove the
tie rod assembly. Heating the tie rod
arm will soften parts. Damage to
components will result.

1. Remove and discard tie rod arm 7⁄8"
fasteners.

Tie Rod End

Tie Rod Arm
7 8

/ " Hex Bolt

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.

Loosen the draw key
locknut until the top of
the locknut is even with
the end of the draw key

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.
Component Replacement

40

17730-311

STEERTEK NXT High Capacity Steer Axle System for Fire and Rescue Vehicles
Figure 9-23

Figure 9-24
Kingpin
Seal

Knuckle
Assembly

Kingpin
Shim
Axle Beam

Kingpin

Kingpin
Seal

Thrust
Bearing

4. If the kingpin is hard to remove, use a hydraulic kingpin remover, refer to the Special Tools
section of this publication.
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.
■■

Kingpin Bushing Driver

■■

Kingpin Bushing Installer / Remover Tool

Removal
1. Place the steering knuckle on a workbench squarely supported.
2. Place the STEERTEK NXT kingpin bushing Installer / Remover tool 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.

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Component Replacement

STEERTEK NXT High Capacity Steer Axle System for Fire and Rescue Vehicles
Figure 9-25

Figure 9-26

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.
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 driver.
5. Install the kingpin installer/remover tool.

Component Replacement

42

17730-311

STEERTEK NXT High Capacity Steer Axle System for Fire and Rescue Vehicles
Figure 9-31

NOTE the
location of the
grease channel

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

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 Reaming procedure in this section.
Figure 9-33

Figure 9-34

Figure 9-35

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.

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STEERTEK NXT High Capacity Steer Axle System for Fire and Rescue Vehicles
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.

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 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"

Component Replacement

44

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

17730-311

STEERTEK NXT High Capacity Steer Axle System for Fire and Rescue Vehicles
Kingpin Bushing Reaming
You will need
■■ Adjustable Reaming Tool, refer to Special Tools section of this publication.

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.
Figure 9-38

1. Place the knuckle in a vise with
brass jaws, see Figure 9-38.
2. Install the pilot in the lower kingpin
bore.
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.

3. Install the adjustable reamer into the pilot.
4. Slide the reamer into the upper bushing and into the pilot until the reamer blades touch the
bushing.
Figure 9-39

17730-311

Figure 9-40

45

Component Replacement

STEERTEK NXT High Capacity Steer Axle System for Fire and Rescue Vehicles
5. Rotate the reamer with a light DOWNWARD pressure. Do not apply too much force. Rotate
the reamer smoothly, see Figure 9-39.
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 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
You will Need:
■■

Kingpin Seal Driver / Remover Tool, refer to the Special Tools section in this publication.

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 a kingpin seal Driver / Remover tool and drive the seal firmly into the steering knuckle
assembly with a hammer.
4. Install the kingpin seal until it bottoms out in the kingpin bore, see Figure 9‑42.
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
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 contact the bottom of the axle beam, see Figures
9-43 and 9-44.
Wear gloves when you install the shims. Shims have sharp edges that can cause
serious personal injury.
Figure 943

Kingpin Seal MUST face
upward towards the axle
The top inner
diameter contacts
the bottom of
the axle beam

Top View

Component Replacement

Bottom View

46

17730-311

STEERTEK NXT High Capacity Steer Axle System for Fire and Rescue Vehicles
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.
Figure 9-44

Figure 9-45

Shim
Upper
Drawkey

Thrust Bearing
and Seal
Assembly

Axle
Lower
Drawkey
Knuckle 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.
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 Figure 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.
Figure 9-46

Figure 9-47

Figure 9-48

Align
Kingpin

Installing
Kingpin

Upper
Drawkey

Verify the word
TOP is stamped
on the kingpin.

Lower
Drawkey

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STEERTEK NXT High Capacity Steer Axle System for Fire and Rescue Vehicles
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.
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

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

4¾" Draw Key
Part No.
75925-002
Back 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.
4. Use one of the following methods to measure the vertical clearance.
■■