Steerable Auxiliary Lift Axle Systems
SUBJECT: Operation and Preventive Maintenance
Procedures
LIT NO: OM-H754
DATE: July 2018
REVISION: C
TABLE OF CONTENTS
Section 1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
Recording Your Model(s) / Serial Number(s) . 2

Section 2

Product Description
Identifying your Lift Axle Suspension(s). . . . . 3
Axle Tag Identification . . . . . . . . . . . . . . . . . . 3
Steerable Models . . . . . . . . . . . . . . . . . . . . . 3

Section 3

Important Safety Notice. . . . . . . . . . . . . . 5

Section 4

Lift Axle Operation
Controlling Inside or Outside-Mounted
Lift Axle Air Control System Kits . . . . . . . . . 9
Raising your Lift Axle. . . . . . . . . . . . . . . . . . . 9
Lowering your Lift Axle . . . . . . . . . . . . . . . . . 9
Reverse Caster Operation . . . . . . . . . . . . . . . 9
Reverse Lockout Operation (if equipped). . . 10

Section 5

Preventive Maintenance
Daily / Pre-trip Operator Inspection . . . . . . . 11
General Inspection . . . . . . . . . . . . . . . . . . . 11
Hendrickson Recommended Maintenance
Intervals. . . . . . . . . . . . . . . . . . . . . . . . . 11
Hendrickson Recommended Lubrication
Specifications. . . . . . . . . . . . . . . . . . . . . 11

Section 6

Air Pressure Load Information
How to Measure Ride Air Spring Extension
and Axle Lift . . . . . . . . . . . . . . . . . . . . . . 12
Air Pressure Load Charts . . . . . . . . . . . . . . . 13

Section 7

Torque Specifications. . . . . . . . . . . . . . . 15

Section 8

Troubleshooting Guide. . . . . . . . . . . . . . 16

Owner’s Manual – Steerable Auxiliary Lift Axle Systems
SECTION 1

Introduction
This publication is intended to acquaint and assist maintenance personnel in the identification, operation
and preventive maintenance of Hendrickson steerable auxiliary lift axle suspension systems. Refer to the
current version of Hendrickson Publication No. TP-H633 for installation and additional service, repair, and
rebuild instructions for such products.
NOTE

Use only Hendrickson Genuine parts for servicing this suspension system.
It is important to read and understand this entire publication prior to operating or performing any maintenance of the product. The information in this publication contains product images, safety information,
product specifications, features and proper maintenance and operating instructions of Hendrickson steerable auxiliary lift axles.
Hendrickson reserves the right to make changes and improvements to its products and publications
at any time. Contact Hendrickson Tech Services for information on the latest version of this manual at
1-800-660-2829 (toll-free U.S. and Canada), 1-740-929-5600 (Outside U.S. and Canada), or email:
liftaxle‌@‌hendrickson‑intl.com.
The latest revision of this publication is also available online at www.hendrickson-intl.com.

Recording Your Model(s) / Serial Number(s)
Please utilize Table 1-1 to record the Model(s) and Serial Number(s) of your suspensions / axles for future
reference to help identify such equipment when contacting Hendrickson Specialty Products – Auxiliary Axle
Systems. This information is necessary for warranty and/or customer service needs. To locate the Model and
Serial Number information refer to Figure 2-1.
Note

Refer to the current version of Hendrickson Publication No. H624 for information on the limited warranty coverage and warranty claims process for Hendrickson auxiliary lift axle suspension systems.

TABLE 1-1

Model

Serial Number

1.
2.
3.
4.
5.
6.
NOTES

Introduction

2

OM-H754

Owner’s Manual – Steerable Auxiliary Lift Axle Systems
SECTION 2

Product Description
Identifying your Lift Axle Suspension(s)
NOTE

All Hendrickson Auxiliary Lift Axles are manufactured with a serial number plate to help in identification, see
Figure 2-1.
When identifying your Hendrickson Auxiliary Lift Axle visually, see Figures 2-2 to 2-6 to compare with your
suspension.

Axle Tag Identification
The Serial Number Label shown in Figure 2-1 is stainless steel label and attached to the body of the
suspension system. The label contains the model and serial number unique to that particular suspension system. These two numbers are important to use when contacting Hendrickson for customer service,
replacement parts and warranty.
Figure 2-1 Serial Number Label

Steerable Models
Hendrickson’s COMPOSILITE family of steerable lift axles for truck and trailer applications, as well as its
TOUGHLIFT LK lift axle for truck applications, deliver reliability, cost-effectiveness and innovation.This lineup
offers a full range of capacities from 10,000 to 25,000 pounds, including axles for roll-off and twin steer
applications. The COMPOSILITE SCT and COMPOSILITE SCO models come equipped with Hendrickson’s
Patented Compliant Tie Rod (CTR) technology and dampening system.
Figure 2-2

COMPOSILITE™ SCT | Truck
The COMPOSILITE SCT, for truck applications, provides capacity ratings of
8,000, 10,000, 13,500 and 20,000 pounds; the most popular being the
SCT13, 13,500 pounds. The line boasts the patented Compliant Tie Rod
(CTR) technology, designed to help lower maintenance costs and increase
uptime by providing a resilient, impact resistant tie rod assembly. The family
also utilizes a fabricated two‑piece axle, designed to increase the strength
and durability while providing significant weight reduction over the existing
I-beam forged design.
Available in 8K, 10K, 13.5K and 20K pound capacities.

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Product Description

Owner’s Manual – Steerable Auxiliary Lift Axle Systems
Figure 2-3

COMPOSILITE™ SCW(B) | TRAILER
The COMPOSILITE SCW, for trailer applications, provides capacity ratings of
8,000, 10,000, 13,500 and 20,000 pounds; available in weld-on or bolt on
configurations. The trailer mount COMPOSILITE SC Series boasts a Heavy-duty
(HD) Compliant Tie Rod (CTR) with a round tube tie rod and the dampening
bushing ends of the popular CTR system. The family also utilizes a fabricated
two piece axle, designed to increase the strength and durability while providing significant weight reduction over the existing I-beam forged design.
Available in 8K,10K,13.5K and 20K pound capacities.
Available in weld-on (SCW) or bolt-on (SCB).

(Pictured enhancements may differ from options received; please see Hendrickson
Literature number TB-H755 for details on enhancements for received capacity).

Figure 2-4

COMPOSILITE™ TVR | TWIN STEER TRUCK
The COMPOSILITE TVR twin steer design, with similar features to the
COMPOSILITE SC family, includes a transverse V-Rod feature that provides an
increased lateral load rating. The TVR includes an integrated steering arm as
well as inboard rail‑mounted upper air spring plates and a standard tubular
tie rod. It is offered in capacities up to 20,000 pounds and utilizes a fabricated two-piece axle engineered to optimize strength and durability.
Available in 20K pound capacity.

Figure 2-5

COMPOSILITE™ SCO | roll off TRUCK
The COMPOSILITE SCO, available in 13,500 and 20,000 capacities, mounts to
the inside of the frame to help provide maximum clearance from cylinder beams,
attachments and sliding components for roll-off applications. Its scalloped hangers,
inbound positioned ride springs and parallelogram components aid in the clearance
around roll-off cylinders.
Available in 13K and 20K pound capacities.

Figure 2-6

TOUGHLIFT™ LK | DUAL TIRE TRUCK
The TOUGHLIFT LK, the leading kingpin suspension and axle is designed
around the proven HLM concept for rigorous environments and incorporates
Hendrickson’s popular QUIK-ALIGN® feature and TRI‑FUNCTIONAL® Bushings. The
fabricated knuckle design minimizes kingpin offset for a more efficient package
while incorporating a fully integrated system designed by Hendrickson.
Available in 25K pound capacity.

Product Description

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OM-H754

Owner’s Manual – Steerable Auxiliary Lift Axle Systems
SECTION 3

Important Safety Notice
Proper installation, maintenance, service, and repair is important for the reliable operation of the suspension. The procedures recommended by Hendrickson and described in this technical publication are
methods of performing such maintenance, service and repair.
All safety related information should be read carefully to help prevent personal injury and to assure that
proper methods are used. Improper installation, maintenance, service or repair may damage the vehicle,
cause personal injury, render it unsafe in operation, or void manufacturer’s warranty.
Failure to follow the safety precautions in this manual can result in personal injury and/or property damage.
Carefully read and understand all safety related information within this publication, on all decals and in
all such materials provided by the vehicle manufacturer before conducting any installation, maintenance,
service or repair.
■■

EXPLANATION OF SIGNAL WORDS

Hazard “Signal Words” (Danger-Warning-Caution) appear in various locations throughout this publication.
Information accented by one of these signal words must be observed to help minimize the risk of personal
injury to service personnel, or possibility of improper service methods which, may damage the vehicle or
render it unsafe.
This is the safety alert symbol. It is used to alert you to potential personal injury hazards. Obey
all safety messages that follow this symbol to avoid possible injury or death.
Additional Notes or Service Hints are utilized to emphasize areas of procedural importance and
provide suggestions for ease of repair. The following definitions indicate the use of these signal words as
they appear throughout the publication.
Indicates AN IMMINENTLY HAZARDOUS SITUATION which, IF NOT AVOIDED WILL result in SERIOUS injury
OR DEATH.
Indicates A POTENTIAL HAZARDOUS SITUATION WHICH, IF NOT AVOIDED Can RESULT in SERIOUS injury OR
DEATH.
Indicates A POTENTIAL HAZARDOUS SITUATION WHICH, IF NOT AVOIDED MAY RESULT IN MINOR OR
MODERATE INJURY.

NOTE

An operating procedure, practice condition, etc. which is essential to emphasize.

SERVICE HINT

A helpful suggestion that will make the servicing being performed a little easier and/or faster.

The torque symbol alerts you to tighten fasteners to a specified torque value. Refer to Torque
Specifications Section of this publication.

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Important Safety Notice

Owner’s Manual – Steerable Auxiliary Lift Axle Systems
■■

Safety precautions

LIFT AXLE RAPID MOVEMENT
LIFT AXLE RAPID MOVEMENT CAN CAUSE SEVERE PERSONAL INJURY OR DEATH.
IF LIFT AXLE IS OPERATED BY AN AUTOMATIC OR SEMI‑AUTOMATIC LIFT AXLE CONTROL SYSTEM, SUCH SYSTEM
MAY CAUSE LIFT AXLE TO AUTOMATICALLY RAISE OR LOWER UNDER DIFFERENT CONDITIONS.
LIFT AXLE ACTIVATION AND MOVEMENT MAY VARY DEPENDING ON THE BRAND, CONFIGURATION, AND
OPERATING CONDITION OF THE LIFT AXLE CONTROL SYSTEM AND / OR OTHER FACTORS. READ, UNDERSTAND,
AND COMPLY WITH ALL APPLICABLE OPERATING INSTRUCTIONS AND SAFETY INFORMATION PROVIDED BY THE
LIFT AXLE CONTROL SYSTEM MANUFACTURER AND VEHICLE MANUFACTURER.
ENSURE ALL PERSONNEL ARE CLEAR OF LIFT AXLE BEFORE AND DURING VEHICLE LOADING AND LIFT AXLE
ACTIVATION UP OR DOWN.

LIFT AXLE ACTIVATION
DO NOT LOWER LIFT AXLE WHILE the VEHICLE IS MOVING IN REVERSE OR TRAVELING AT MORE THAN 15 MPH.
FAILURE TO DO SO CAN CAUSE COMPONENT DAMAGE.

REVERSE LOCKOUT OPERATION
DO NOT ACTUATE STEERABLE LIFT AXLE REVERSE LOCKOUT FEATURE (IF EQUIPPED) WHILE VEHICLE IS
TURNING. FAILURE TO DO SO CAN CAUSE COMPONENT DAMAGE.
BEFORE TRAVELING IN REVERSE:
• Ensure STEERABLE LIFT AXLE REVERSE LOCKOUT FEATURE (IF EQUIPPED) is properly actuated.
• RAISE ALL STEERABLE LIFT AXLES NOT EQUIPPED WITH REVERSE LOCKOUT FEATURE.
FAILURE TO DO SO CAN CAUSE COMPONENT DAMAGE.

LOAD CAPACITY
ADHERE TO THE PUBLISHED CAPACITY RATINGS FOR THE auxiliary axle. ADD-ON AXLE ATTACHMENTS (I.E.
SLIDING FIFTH WHEELS) AND OTHER LOAD TRANSFERRING DEVICES CAN INCREASE THE auxiliary axle
LOAD ABOVE THE RATED AND APPROVED CAPACITIES WHICH CAN RESULT IN FAILURE AND Adverse vehicle
handling, POSSIBLY CAUSING PERSONAL INJURY OR PROPERTY DAMAGE.

DAILY/PRE-TRIP OPERATOR INSPECTION
Daily (and before each trip) inspect all lift axle components for proper operating condition
and proper installation to the truck / trailer frame. This essential Daily / Pre-trip Operator
Inspection must also include a visual inspection of all wheel seals and gaskets for
leaks, a verification of proper oil level in the hubs (if applicable), inspection of all lift and
ride air‑springs for wear, and inspection of all tires for proper inflation an abnormal
wear patterns. Identify and repair / replace any loose, damaged or improperly installed
components. Refer to the current version of Hendrickson Publication No. TP-H633 for
additional service, repair, and rebuild instructions.

REPAIR AND RECONDITIONING
THE REPAIR OR RECONDITIONING OF auxiliary axle COMPONENTS that are bent, damaged or out
of specification IS NOT ALLOWED. ANY AXLE COMPONENTS FOUND TO BE DAMAGED OR OUT OF
SPECIFICATION, MUST BE REPLACED. AXLE COMPONENTS CANNOT BE BENT, WELDED, HEATED, OR REPAIRED
WITHOUT REDUCING THE STRENGTH OR LIFE OF THE COMPONENT. FAILURE TO FOLLOW THESE GUIDELINES
CAN CAUSE Adverse vehicle handling, POSSIBLE PERSONAL INJURY, DEATH, OR PROPERTY DAMAGE AND
WILL VOID APPLICABLE WARRANTIES.

PERSONNEL PROTECTIVE EQUIPMENT
ALWAYS WEAR PROPER EYE PROTECTION AND OTHER REQUIRED PERSONAL PROTECTIVE EQUIPMENT TO HELP
PREVENT PERSONAL INJURY WHEN YOU PERFORM VEHICLE MAINTENANCE, REPAIR OR SERVICE.

Important Safety Notice

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OM-H754

Owner’s Manual – Steerable Auxiliary Lift Axle Systems
PROCEDURES AND TOOLS
A MECHANIC USING A SERVICE PROCEDURE OR TOOL,that HAS NOT BEEN RECOMMENDED BY HENDRICKSON,
MUST FIRST SATISFY HIMSELF THAT NEITHER HIS SAFETY NOR THE VEHICLE’S SAFETY WILL BE JEOPARDIZED
BY THE METHOD OR TOOL SELECTED. INDIVIDUALS DEVIATING IN ANY MANNER FROM THE INSTRUCTIONS
PROVIDED ASSUME ALL RISKS OF POTENTIAL PERSONAL INJURY OR DAMAGE TO EQUIPMENT INVOLVED.

FASTENERS
DISCARD USED FASTENERS. ALWAYS USE NEW FASTENERS TO COMPLETE A REPAIR. FAILURE TO DO SO
COULD RESULT IN FAILURE OF THE PART OR MATING COMPONENTS, Adverse vehicle handling, PERSONAL
INJURY, OR PROPERTY DAMAGE.
LOOSE OR OVER-TORQUED FASTENERS CAN CAUSE COMPONENT DAMAGE, Adverse vehicle handling,
PROPERTY DAMAGE, OR SEVERE PERSONAL INJURY. MAINTAIN CORRECT TORQUE VALUE AT ALL TIMES. CHECK
TORQUE VALUES ON A REGULAR BASIS AS SPECIFIED, USING A REGULARLY CALIBRATED TORQUE WRENCH.
TORQUE VALUES SPECIFIED IN THIS TECHNICAL PUBLICATION ARE FOR HENDRICKSON SUPPLIED FASTENERS
ONLY. IF NON‑HENDRICKSON FASTENERS ARE USED, FOLLOW TORQUE Specifications LISTED IN THE VEHICLE
MANUFACTURER’S SERVICE MANUAL.

MODIFYING COMPONENTS
DO NOT MODIFY OR REWORK PARTS WITHOUT AUTHORIZATION FROM HENDRICKSON. DO NOT SUBSTITUTE
REPLACEMENT COMPONENTS NOT AUTHORIZED BY HENDRICKSON. USE OF MODIFIED, REWORKED,
SUBSTITUTE OR REPLACEMENT PARTS NOT AUTHORIZED BY HENDRICKSON MAY NOT MEET HENDRICKSON’S
SPECIFICATIONS, AND CAN RESULT IN FAILURE OF THE PART, Adverse vehicle handling, POSSIBLE
PERSONAL INJURY OR PROPERTY DAMAGE, AND WILL void applicable Warranties. USE ONLY
HENDRICKSON-AUTHORIZED REPLACEMENT PARTS.
THE VEHICLE MANUFACTURER SHOULD BE CONSULTED BEFORE MAKING ANY CHANGES TO THE VEHICLE’S
FRAME. TYPICALLY, CUTTING OR ALTERING THE VEHICLE’S FRAME OR SIDE RAIL IS NOT PERMITTED AND MAY
AFFECT THE MANUFACTURER’S WARRANTY COVERAGE.
ANY INSTALLATION DEVIATIONS MUST BE APPROVED IN WRITING BY HENDRICKSON’S PRODUCT ENGINEERING
DEPARTMENT. FAILURE TO COMPLY WITH ANY OF THE ABOVE WILL void applicable warranties.

DAMAGED AXLE COMPONENTS
IF A VEHICLE EQUIPPED WITH A HENDRICKSON AUXILIARY AXLE IS INVOLVED IN A CRASH, A THOROUGH
INSPECTION OF THE AXLE MUST BE PERFORMED NOTING THE CONDITION OF THE AXLE BEAM, KINGPINS,
AND KNUCKLE ASSEMBLIES, INCLUDING THE AREAS OF AXLE-TO-KINGPIN INTERFACE, FOR ANY DAMAGE,
GAPS, KINGPIN MOVEMENT OR PLAY. IF ANY COMPONENT APPEARS DAMAGED, OR THE KINGPINS APPEAR TO
CONTAIN ANY DAMAGE, GAPS, MOVEMENT OR PLAY, THE COMPLETE AXLE ASSEMBLY MUST BE REPLACED.
IN ADDITION, IN THE EVENT A CRASH RESULTS IN EXCESSIVE SIDE LOAD DAMAGE TO ADJACENT PARTS, SUCH AS
A BENT WHEEL, HUB, OR SPINDLE, IT IS STRONGLY RECOMMENDED TO REPLACE SUCH ADJACENT PARTS AND
THE COMPLETE AXLE ASSEMBLY.
CONTACT HENDRICKSON TECHNICAL SERVICES DEPARTMENT WITH ANY QUESTIONS. FAILURE TO REPLACE ANY
DAMAGED COMPONENTS CAN CAUSE Adverse vehicle handling, POSSIBLE PERSONAL INJURY, DEATH, OR
PROPERTY DAMAGE AND WILL VOID ANY APPLICABLE WARRANTIES.

SUPPORT THE VEHICLE PRIOR TO SERVICING
Place the vehicle on a level floor and chock the wheels to help prevent the vehicle from
moving. Prior to servicing a vehicle in the raised position, properly support the vehicle with
safety stands. Do not work around or under a raised vehicle supported only with floor
jacks or other lifting devices, failure to do so can cause death, personal injury or damage
to components.

IMPROPER JACKING METHOD
IMPROPER JACKING METHOD CAN CAUSE STRUCTURAL DAMAGE AND RESULT IN Adverse vehicle handling,
SEVERE PERSONAL INJURY OR DEATH. DO NOT USE AXLE BEAM OUTBOARD OF AXLE SPRING SEATS. REFER TO
VEHICLE MANUFACTURER FOR PROPER JACKING INSTRUCTIONS.

OM-H754

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Important Safety Notice

Owner’s Manual – Steerable Auxiliary Lift Axle Systems
SUPPORT THE lift axle PRIOR TO SERVICING
Place the vehicle on a level floor and chock the wheels to help prevent the vehicle from
moving. Prior to servicing a lift axle in the raised position, (1) properly support the lift axle
with safety stands, and (2) release all air pressure in the lift axle air springs and ride springs.
Do not work around or under a raised lift axle supported only with floor jacks or other
lifting devices, failure to do so can cause death, personal injury or damage to components.

AIR SPRINGS
AIR SPRING ASSEMBLIES MUST BE DEFLATED PRIOR TO LOOSENING ANY adjacent 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.

Air springs
EXHAUST ALL PRESSURE IN LIFT AXLE AIR SPRINGS AND VEHICLE AIR SYSTEM BEFORE WORKING ON OR
AROUND LIFT AXLE. FAILURE TO DO SO CAN CAUSE SEVERE PERSONAL INJURY OR DEATH.

Air springs
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 SEVERE PERSONAL INJURY, DEATH, OR PROPERTY DAMAGE.

Air springs
Inflate the suspension slowly and make sure the rubber bladder of the air spring inflates
uniformly and is not binding. Failure to do so can cause damage to the air spring AND / OR
mounting brackets and WILL Void applicable warranties.

OFF ROADWAY TOWING
HENDRICKSON DOES NOT RECOMMEND TOWING A VEHICLE BY THE AUXILIARY AXLE. DOING SO WILL DAMAGE
THE AXLE and WILL Void applicable warranties.

Parts Cleaning
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:

1.
2.
3.
4.
5.

WEAR PROPER EYE PROTECTION.
WEAR CLOTHING THAT PROTECTS YOUR SKIN.
WORK IN A WELL VENTILATED AREA.
DO NOT USE GASOLINE OR SOLVENTS THAT CONTAIN GASOLINE. GASOLINE 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. DOING SO WILL CAUSE DAMAGE TO THE PARTS AND void applicable warranties.

LIFT AXLE CAMBER
UNAUTHORIZED WELDING OR MODIFICATIONS CAN CAUSE CRACKS OR OTHER lift AXLE STRUCTURAL
DAMAGE AND RESULT IN Adverse vehicle handling, SEVERE PERSONAL INJURY OR DEATH. DO NOT BEND,
WELD OR MODIFY AXLE WITHOUT AUTHORIZATION FROM HENDRICKSON. 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, can CAUSE Adverse vehicle
handling, Possibly CAUSING PERSONAL INJURY OR PROPERTY DAMAGE and WILL Void applicable
warranties.

Important Safety Notice

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Owner’s Manual – Steerable Auxiliary Lift Axle Systems
SECTION 4

Lift Axle Operation
Controlling Inside or Outside-Mounted Lift Axle
Air Control System Kits
1. If vehicle is already running, please proceed to the appropriate section below.
2. Set parking brake of truck.
3. Turn your vehicle ignition to on position.
4. Press ignition start switch and release when engine is started.
5. Allow the vehicle to idle until the vehicle’s air system pressure has reached compressor cut-out point
(typically 120 psi).

Raising your Lift Axle
1. If the lift axle controls are mounted inside the vehicle cab, move the control panel mechanism (pull to
lift) to the axle up position.
2. If the lift axle controls are mounted outside the vehicle cab, ensure vehicle is stopped and parking
brake is set. Exit vehicle, go to and open air control enclosure. Move the control panel mechanism to
the axle up position.
3. Visually confirm that the lift axle is lifting.
NOTE

Air system pressure may drop during suspension lifting process.
4. Lift axle should be completely lifted when air system pressure returns to the air compressor cut‑out
point (typically 120 psi).

Lowering your Lift Axle
1. If the lift axle controls are mounted inside the vehicle cab, move the control panel mechanism (push
to lower) to the axle down position.
DO NOT LOWER LIFT AXLE WHILE the VEHICLE IS MOVING IN REVERSE OR TRAVELING AT MORE THAN 15 MPH.
FAILURE TO DO SO CAN CAUSE COMPONENT DAMAGE.

2. If the lift axle controls are mounted outside the vehicle cab, ensure the vehicle is stopped and parking
brake is set. Exit vehicle, go to and open air control enclosure. Move the control panel mechanism to
the axle down position.
3. Using the regulator, adjust air system pressure on the gauge to appropriate air pressure for vehicle load
conditions, see Air Pressure Load Information Section in this publication.
NOTE

Air system pressure may drop during suspension lowering process.
4. Lift axle should be completely lowered and supporting pre-determined load when air system pressure
returns to the air compressor cut-out point (typically 120 psi).

Reverse Caster Operation
DO NOT LOWER LIFT AXLE WHILE the VEHICLE IS MOVING IN REVERSE OR TRAVELING AT MORE THAN 15 MPH.
FAILURE TO DO SO CAN CAUSE COMPONENT DAMAGE.

To ensure proper operation of the Hendrickson steerable lift axles with the reverse caster feature:
1. The lift axle must be in down position and the vehicle transmission must be in reverse.

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Lift Axle Operation

Owner’s Manual – Steerable Auxiliary Lift Axle Systems
Reverse Lockout Operation (if equipped)
DO NOT ACTUATE STEERABLE LIFT AXLE REVERSE LOCKOUT FEATURE (IF EQUIPPED) WHILE VEHICLE IS
TURNING. FAILURE TO DO SO CAN CAUSE COMPONENT DAMAGE.
BEFORE TRAVELING IN REVERSE:
• Ensure STEERABLE LIFT AXLE REVERSE LOCKOUT FEATURE (IF EQUIPPED) is properly actuated.
• RAISE ALL STEERABLE LIFT AXLES NOT EQUIPPED WITH REVERSE LOCKOUT FEATURE.
FAILURE TO DO SO CAN CAUSE COMPONENT DAMAGE.

Actuation of reverse lockout will depend on the model of lift axle control kit installed on the vehicle and any
design restrictions in place.
Refer to the current version of Hendrickson Publication No. OM-H719 for lift axle control kits operation
instructions. Contact Hendrickson (800.660.2829) for information on Reverse Lockout Operation design
restrictions.

Lift Axle Operation

10

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Owner’s Manual – Steerable Auxiliary Lift Axle Systems
SECTION 5

Preventive Maintenance
Daily / Pre-trip Operator Inspection
Daily (and before each trip) inspect all lift axle components for proper operating condition and proper
installation to the truck/trailer frame. This essential Daily/Pre-trip Operator Inspection must also include
a visual inspection of all wheel seals and gaskets for leaks, a verification of proper oil level in the hubs (if
applicable), inspection of all lift and ride air-springs for wear, and inspection of all tires for proper inflation
and abnormal wear patterns. Identify and repair/replace any loose, damaged or improperly installed components. Refer to the current version of Hendrickson Publication No. TP-H633 for additional service, repair,
and rebuild instructions.
NOTE

Replace any safety decals that are faded, torn, missing, illegible, or otherwise damaged. Contact
Hendrickson to order replacement labels.

General Inspection
Following appropriate inspection procedure is important to help ensure the proper maintenance and operation of the lift axle system and component parts function to their highest efficiency.
■■

■■

Fasteners — Inspect for any loose or damaged fasteners on the entire lift axle suspension. Make sure
all fasteners are tightened to the specified torque. Refer to the Torque Specifications Section in this
publication if fasteners are supplied by Hendrickson, non‑Hendrickson fasteners, refer to the vehicle
manufacturer. Use a calibrated torque wrench to check torque in a tightening direction. As soon as the
fastener starts to move, record the torque. Correct the torque if necessary. Replace any worn or damaged fasteners.
Air springs — Visually Inspect suspension for any debris rubbing against air springs or signs of chaffing. Clear debris and/or replace air springs as necessary.

Hendrickson Recommended Maintenance Intervals
COMPONENT

Initial
Break‑in

Intervals After initial break‑in

PROCEDURE

Wheel Bearings

8,000 mi. or every 2 months, whichever
comes first

Verify end play is between 0.001" and 0.005" adjust
as required, and grease or oil

Tie Rod Ends

10,000 mi. or monthly, whichever comes first

Verify torque, inspect for leaking, and lubricate

10,000 mi. or 6 months, whichever comes first

Check for wear and grease

Kingpin Bushings

5,000 mi.