1. Place the vehicle on level floor.
2. Chock the wheels.
3. Raise the frame.
4. Support the vehicle with frame stands.
PRIOR TO AND DURING DEFLATION AND INFLATION OF THE AIR SUSPENSION SYSTEM, ENSURE 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.

5. See additional Air Spring Cautions and Warnings in the Important Safety Notice Section of this
publication prior to inflating or deflating the suspension system.
6. Exhaust the air from the air system as per the vehicle manufacturer’s instructions.
IF THE AIR SPRING IS TO BE RE-INSTALLED; INSPECT LOCK-TABS FOR DAMAGE OR CRACKS PRIOR TO
RE-INSTALLATION. CARE MUST BE TAKEN TO REMOVE DIRT AND DEBRIS FROM THE PUSH-TO-CONNECT
FITTING. FAILURE TO DO SO CAN RESULT IN THE PUSH-TO-CONNECT FITTING FAILING TO SEAL WITH
THE AIR LINE.

7. Disconnect the air line to the air spring.
8. Raise the frame to allow for air spring removal.
9. Separate the air spring from the upper air spring bracket by applying downward pressure on
air spring, see Figure 9-1, pushing outward on the lock-tabs outside the bracket, and inward
on inlet lock-tabs. This will dislodge the air spring from the upper air spring bracket.
10. Apply upward pressure between the base of the air spring and the top pad. This will dislodge
the air spring from the top pad, see Figure 9-2.
11. Remove the air spring.

17730-319

35

Component Replacement

AIRTEK® for Tiffin Motorhome Chassis
FIGURE 9-1

FIGURE 9-2

ASSEMBLY
1. Insert the air spring into the top pad. Make sure the lock tabs click in place.
2. Compress the air spring and slide into vertical position. There is a locating nodule on the air
spring to index the position in the upper air spring bracket.
3. Pull the air spring up into the upper air spring bracket until the air spring snaps into place in
the upper air spring bracket. Verify all four lock-tabs are engaged, see Figure 9‑3.
FIGURE 9-3

SERVICE HINT

When replacing or installing nylon
air line tubing into quick-connect fittings it is critical that the end of the
air line is cut square. Improper cut
of the end of the air line tubing can
cause the air line to seat improperly
in the quick connect fitting causing
air leakage.
4. Install the air line into the air
spring.
­­
WHEN
SERVICING THE VEHICLE OR ATTACHING AN AIR SPRING AND THE VEHICLE IS ON THE GROUND,
PRIOR TO AIRING THE SUSPENSION SYSTEM MAKE CERTAIN THE AIR SPRING LOCATOR IS INDEXED
INTO THE UPPER AIR SPRING BRACKET PROPERLY, AND THE AIR SPRING IS FULLY SEATED ON THE
SPRING TOP PAD. FAILURE TO FOLLOW THESE INSTRUCTIONS CAN RESULT IN PREMATURE AIR SPRING
FAILURE, CAUSE PERSONAL INJURY, OR PROPERTY DAMAGE.

5. See additional Air Spring Cautions and Warnings in the Important Safety Notice Section of this
publication prior to inflating or deflating the suspension system.
6. Inflate the suspension to normal ride height per vehicle manufacturer’s guidelines.
7. Check the air spring for leaks.
8. Check the ride height and adjust if necessary as per the vehicle manufacturer’s specifications.
9. Remove the wheel chocks.

Component Replacement

36

17730-319

AIRTEK® for Tiffin Motorhome Chassis
FRONT LEAF SPRING FRAME HANGER
DISASSEMBLY
1. Place the vehicle on level floor.
2. Chock the wheels.
3. Raise the frame.
4. Support the vehicle with frame stands.
5. Suspend the front axle from the shock absorbers.
PRIOR TO AND DURING DEFLATION AND INFLATION OF THE AIR SUSPENSION SYSTEM, ENSURE 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.

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. Exhaust the air from the air system as per the vehicle manufacturer’s instructions.
8. Remove the air lines from air springs.
9. Remove the ¾" spring eye bolt, washers and locknut.
SERVICE HINT

A bottle jack may be required to raise the axle slightly to facilitate removal of the spring eye bolt.
10. Remove the frame mounting fasteners from the hanger per vehicle manufacturer’s
instructions.
11. Remove the hanger from the vehicle, see Figure 9-4.
FIGURE 9-4

ASSEMBLY
1. Install the new hanger on
the frame.
2. Install new frame fasteners
per vehicle manufacturer’s
instructions.

¾" Shackle Bolt
Tightening Torque
400 ± 20 ft. lbs.
(543 ± 27 Nm)

3. Install the new ¾" spring
eye bolt from the outboard
side of the hanger, washers
and locknut, see Figure 9‑4.

¾" Spring Eye Bolt
Tightening Torque
400 ± 20 ft. lbs. (543 ± 27 Nm)

4. Remove the frame stands
and lower frame.
5. See additional Air Spring Cautions and Warnings in the Important Safety Notice Section of this
publication prior to inflating or deflating the suspension system.
6. Install the air lines into the air springs.
7. Inflate the suspension to normal ride height as per the vehicle manufacturer’s specifications.
8. Tighten ¾" locknut to

400 ± 20 foot pounds torque in loaded condition.

9. Remove the wheel chocks.

17730-319

37

Component Replacement

AIRTEK® for Tiffin Motorhome Chassis
REAR SHACKLE BRACKET
DISASSEMBLY
1. Place the vehicle on level floor.
2. Chock the wheels.
3. Raise the frame.
4. Support the vehicle with frame stands.
5. Suspend the front axle from the shock absorbers.
PRIOR TO AND DURING DEFLATION AND INFLATION OF THE AIR SUSPENSION SYSTEM, ENSURE 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.

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. Exhaust the air from the air system as per the vehicle manufacturer’s instructions.
8. Remove the air lines from air springs.
9. Remove and discard the rear ¾" spring eye and shackle fasteners.
10. Remove and discard shackle plates.
SERVICE HINT

A bottle jack may be required to raise the axle slightly to facilitate removal of the spring eye bolt.
11. Remove the frame mounting fasteners from the rear shackle bracket per vehicle manufacturer’s guidelines.
12. Remove the shackle bracket from the vehicle, see Figure 9-5.
13. Inspect the shackle assembly for excessive wear or damage, refer to the Preventive
Maintenance Section of this publication. If damaged or worn excessively, replace with genuine Hendrickson parts as detailed in the Component Replacement Section of this publication.

ASSEMBLY
1. Install the shackle bracket on the frame with new frame fasteners per vehicle manufacturer’s
guidelines.
2. Install the shackle plates with the new ¾" bolts, washers and locknuts. Snug the shackle bolts.
DO NOT tighten at this time.
FIGURE 9-5

3. Remove the frame stands and lower the frame.
4. See additional Air Spring Cautions and
Warnings in the Important Safety Notice
Section of this publication prior to inflating or
deflating the suspension system.

Shackle Bracket
¾" Washer

5. Install the air lines into the air springs.
6. Inflate the suspension to normal ride height as
per the vehicle manufacturer’s specifications.

Leaf Spring
Assembly
¾" Bolt

¾" Shackle Locknut
Tightening Torque
400 ± 20 ft. lbs.
(543 ± 27 Nm)

7. Tighten ¾" shackle locknuts to 400 ± 20
foot pounds torque in loaded condition, see
Figure 9-5.
8. Remove the wheel chocks.

Shackle Plate

Component Replacement

38

17730-319

AIRTEK® for Tiffin Motorhome Chassis
LEAF SPRING ASSEMBLY
DISASSEMBLY
1. Place the vehicle on a level floor.
2. Chock the wheels.
3. Exhaust the air from the air system as per the vehicle manufacturer’s instructions.
4. Install a floor jack with a 4 inch lifting plate below the axle and raise the truck.
5. Remove the tires.
6. Install frame stands behind the rear spring mounts. It may be necessary to remove peripheral
components for installation of the frame stands.
PRIOR TO AND DURING DEFLATION AND INFLATION OF THE AIR SUSPENSION SYSTEM, ENSURE 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.

7. Lower the jack allowing the axle to hang, but DO NOT remove the jack from the axle.
8. Loosen both front spring eye bolts, but DO NOT remove the bolts.
9. Loosen the ¾" shackle pivot bolts.
10. Remove and discard both rear spring eye bolts.
11. Remove and discard both lower shock absorber mounting fasteners and spacers.
SERVICE HINT

To ease in the removal of the leaf spring eye bolts, it may be necessary to raise or lower the
axle slightly.
12. Disconnect the air lines at the air springs.
13. Disconnect the bottom of the air springs from the top pad per the Air Spring Component
Disassembly in this section.
DO NOT USE A CUTTING TORCH TO REMOVE CLAMP GROUP BOLTS OR ATTACHING FASTENERS. THE
USE OF SUCH HEAT ON SUSPENSION COMPONENTS CAN ADVERSELY AFFECT THE STRENGTH OF
THESE PARTS. A COMPONENT DAMAGED IN THIS MANNER CAN RESULT IN THE LOSS OF VEHICLE
CONTROL AND POSSIBLE PERSONAL INJURY OR PROPERTY DAMAGE.

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.
14. Loosen the clamp group locknuts for the leaf spring that IS NOT being replaced.
15. Lower the jack allowing the suspension to pivot down out of the rear hanger clamps.
16. Remove and discard the clamp group fasteners from the leaf spring being replaced.
UNAUTHORIZED TAMPERING OF INTEGRATED AXLE SPRING SEATS CAN CAUSE COMPONENT AND
STRUCTURAL DAMAGE AND RESULT IN LOSS OF VEHICLE CONTROL, SEVERE PERSONAL INJURY OR
DEATH, PROPERTY DAMAGE, AND WILL VOID ANY APPLICABLE WARRANTY.
■

NOTE

DO NOT REMOVE, MODIFY OR REPLACE INTEGRATED AXLE SPRING SEAT OR FASTENERS

Contact Hendrickson Tech Services for any questions regarding STEERTEK NXT axle spring seats
and / or fasteners.
17. Remove the top pad, galvanized liner from the leaf spring assembly that is going to be
replaced, see Figure 9-6.
THE WEIGHT OF THE LEAF SPRING ASSEMBLY IS APPROXIMATELY 76 POUNDS. CARE SHOULD BE TAKEN
AT REMOVAL AND INSTALLATION TO PREVENT PERSONAL INJURY OR DAMAGE TO COMPONENTS.

18. Remove the leaf spring assembly. Approximate weight of the leaf spring is 76 pounds.
17730-319

39

Component Replacement

AIRTEK® for Tiffin Motorhome Chassis
ASSEMBLY
THE WEIGHT OF THE LEAF SPRING ASSEMBLY IS APPROXIMATELY 76 POUNDS. CARE SHOULD BE TAKEN
AT REMOVAL AND INSTALLATION TO PREVENT PERSONAL INJURY OR DAMAGE TO COMPONENTS.

1. Install the new leaf spring assembly with the galvanized liner on the axle. Approximate weight
of the leaf spring is 76 pounds.
2. Verify that the dowel pin is engaged properly in the axle spring seat, see Figure 9-6.
3. Install the FRONT spring eye bolt and fastener, snug but DO NOT tighten at this time.
4. Install the top pad on top of the leaf spring.
5. Install the new clamp group fasteners. New clamp group fasteners must be used when the
clamp group is removed, to prevent premature bolt fatigue.
6. Snug the clamp group, DO NOT tighten to torque at this time.
7. Raise the axle and the REAR spring assemblies into the rear spring hangers.
8. Install the rear spring eye bolts in the rear hangers, snug but DO NOT tighten at this time, see
Figure 9-6.
9. Install the lower shock mounting bolts to axle seat from the inboard side to the outboard side
and attach fasteners and spacers.
10. Install the air spring.
FIGURE 9-6
Frame Hanger
Air Spring Assembly

Rear Hanger

¾" Bolt
¾" Washer

Shock
Absorber

¾" Locknut
Tightening Torque
400 ± 20 ft. lbs.
(543 ± 27 Nm)
¾" Locknut
Tightening Torque
130 ± 5 ft. lbs.
(177 ± 6 Nm)

¾" Bolt

¾" Locknut
Tightening Torque
400 ± 20 ft. lbs.
(543 ± 27 Nm)
Rear Shackle Plate

Leaf Spring
Axle Seat

Axle & Kingpin
Assembly

¾" Clamp Group Locknuts
Tightening Torque
295 ± 10 ft. lbs.(400 ± 13 Nm)

¾" Washer

Component Replacement

40

17730-319

AIRTEK® for Tiffin Motorhome Chassis
IMPORTANT NOTE

Only the weight of the axle should be on the spring at the time of the front and rear spring
eye tightening torque. See the Spring Eye Re-torque procedure in the Alignment & Adjustments
Section of this publication.
11. Install the tires.
12. Raise the vehicle and remove the frame supports and load the front axle and then lower
the vehicle.
13. See additional Air Spring Cautions and Warnings in the Important Safety Notice Section of this
publication prior to inflating or deflating the suspension system.
14. Install air lines, and air up system.
15. Tighten the lower shock mounting bolts to
16. Tighten the rear spring eye fasteners to
condition.

130 ± 5 foot pounds torque.
400 ± 20 foot pounds torque in the loaded

17. Install the air springs into the top pads per the Air Spring Component Assembly instructions in
this publication. Make sure the air spring piston seats into the top pad correctly.
18. Ensure that the clamp group is properly aligned and the hex bolts are seated top pad, see
Figures 9-7 and 9-8.
19. Tighten the clamp group locknuts evenly in 50 foot pounds increments to 295 ± 10 foot
pounds torque in the proper pattern to achieve uniform bolt tension, see Figure 9-9.
20. Check the ride height and adjust if necessary as per the vehicle manufacturer’s specifications.
21. Tighten the front ¾" spring eye bolt locknuts to
be at ride height.

400 ± 20 foot pounds torque. Vehicle must

22. Remove the wheel chocks.
FIGURE 9-7

FIGURE 9-8

FIGURE 9-9

IMPORTANT

IMPORTANT

Ensure that the ¾" Clamp Bolts
are seated properly in the Top Pad

Ensure that Axle
Clamp Group is
properly aligned

¾" Clamp Group Locknuts
Tightening Torque
295 ± 10 ft. lbs. (400 ± 13 Nm)

17730-319

41

Component Replacement

AIRTEK® for Tiffin Motorhome Chassis
SHOCK ABSORBER
NOTE

It is not necessary to replace shock absorbers in pairs if only one shock absorber requires
replacement.
FIGURE 9-10
¾" x 4½"
Bolt

DISASSEMBLY

Upper Shock
Bracket

1. Remove the ¾" lower mounting
bolt, fasteners, and spacer.
2. Remove the ¾" upper mounting
bolt and fasteners.
3. Slide the shock absorber out of the
top pad.

¾" Locknut
Tightening Torque
130 ± 5 ft. lbs.
(177 ± 6 Nm)

Shock
Absorber

4. I n s p e c t t h e s h o c k a b s o r b e r
mounting brackets and hardware
for damage or wear, replace as
necessary.

¾" x 5" Bolt
Shock Spacer

Axle Assembly

¾" Washer

ASSEMBLY
1. Install the shock absorber into the
upper mounting bracket.

¾" Locknut
Tightening Torque 130 ± 5 ft. lbs. (177 ± 6 Nm)

2. Install the upper ¾" shock mounting fasteners.
3. Install the lower shock mounting bolts to the axle seat from the inboard side to the outboard
side and attach fasteners and spacers, see Figure 9-10.
4. Tighten both upper and lower ¾" locknuts to

130 ± 5 foot pounds torque, see Figure 9-10.

FRONT AXLE ASSEMBLY – STEERTEK NXT AXLE
The STEERTEK NXT axle clamp group consists of the top pad, ¾" bolts, washers, and
nylon locknuts.

STEERTEK NXT AXLE REMOVAL
DISASSEMBLY
Refer to Figure 9-11 when replacing the components of the STEERTEK NXT axle.
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 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.

Component Replacement

42

17730-319

AIRTEK® for Tiffin Motorhome Chassis
FIGURE 9-11

Spring Eye Bolt
Leaf Spring

Air Spring
Height Control
Valve Linkage

Top Pad
Spacer
Lower Shock Locknut

¾" Bolts
Rear Shackle
Assembly

Grease Zerk
Upper Grease Cap Assembly

RH Upper
Steering Knuckle

Kingpin Bushing

Roller Bearing

LH Upper
Steering Knuckle

RH Lower
Steering Knuckle

Kingpin Seal
Axle & Kingpin Assembly

Cotter Pin

Roller Bearing

/ " Castle Nut

7 8

Lower
Shock
Bolt

LH Lower
Steering Knuckle

/ " Cap Screws

5 8

¾" Washer

/ " Washer