(ffiTECBNICAL
PROCEDURE
HTB® 400LT Rear Air Suspension
for International® Truck Vehicles
SUBJECT: Service Instructions
LIT NO: 17730-251
DATE: September 2013
REVISION: B

Section 1 Introduction ........................ 2

Section 8

Component Replacement ........... 25

Section 2

Product Description ................. 2

Fasteners .......................... 25

Section 3

Important Safety Notice . ............. 4

Air Spring .......................... 25

Section 4

Parts List . .......................... 8

Section 5

Special Tools ...................... 1o

Section 6

Preventive Maintenance ............. 11

Height Control Valve and Linkage Assembly. 26
Shock Absorber ...................... 27
Longitudinal Torque Rod ............... 27
Longitudinal Torque Rod Bushing ......... 29

Component Inspection ................ 11

Torque Box ......................... 31

U-bolt locknuts ...................... 12
Axle Brackets ........................ 12

Clamp Group (Top Pad, Lower Air Spring
Bracket, U-Bolts) ................... 36

Torque Box ......................... 13

Axle Stop ........................... 39

Lateral Alignment Inspection ............ 13

Frame Hanger ....................... 39

Longitudinal Torque Rods .•............ 13

Cross Member. ...................... 41

Air Fitting Inspection .................. 14

Section 9

Shock Absorber Inspection ............. 14

Section 1O Troubleshooting Guide .............. 45

Section 7 Alignment & Adjustments ........... 16

Section 11 Torque Specifications ............... 46

Plumbing Diagram ................. 44

Ride Height Adjustment ................ 16
Axle Alignment and Adjustments ......... 18
Pinion Angle ........................ 24

(ffiBENDRICKSON
?Qe~HR~sOnUs®

HTB® 400LT for International® Truck Vehicles

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SECTION l

Introduction
This publication is intended to acquaint and assist maintenance personnel in the preventive
maintenance, service, repair, and rebuild of the HTB® 400LT rear air suspension system for
applicable International Truck Vehicles.

NOTE

Use only Genuine lHl Hendrickson parts for servicing this suspension system.
It is important to read and understand the entire Technical Procedure publication prior to performing any maintenance, service, repair, or rebuild of this product. The information in this
publication contains parts lists, safety information, product specifications, features, proper maintenance, service, repair and rebuild instructions for the HTB 400LT suspension system.
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 1-866-755-5968 (toll-free U.S. and Canada), 1-630-910-2800 (outside
U.S. and Canada) or e-mail: techservices@hendrickson-intl.com.
The latest revision of this publication is also available online at
www. hendrickson-i ntl. com.

SECTION 2

Product Description
The HTB® LT - Lightweight, non-torque reactive rear air suspension system combines superior
ride, improved stability, reduced weight and reduced maintenance. Unique design and components make the HTB 400LT reliable and rugged, as well as the lightest suspension in its class.
Weighing just 810 pounds*, HTB 400LT saves up to 275 pounds compared to industry standard
40,000 pound capacity suspensions.
• Air Springs - HTB LT improves ride over typical trailing-arm suspensions by supporting
the entire load on large volume air springs. HTB LT also has a highly optimized motion ratio
since the air spring and axle travel at the same rate.
• Torque Box - HTB LT's unique, maintenance-free torque box system improves multiaxial stability and control. The parallelogram design controls suspension windup and
corresponding frame rise. Maintaining pinion angles throughout axle travel reduces suspension-induced driveline vibration and extends driveline component life.
• Rubber Bushings -All pivot points come equipped with premium rubber bushings requiring no lubrication. Torque box bushings are designed for long life.
• U-bolts - Re-torque of the clamp group reduced since no twisting is applied to the
clamp group.
• Axle Alignment - The torque box, torque rods and clamp group joints provide consistent
axle alignment and reduce the need for realignment.

* Represents installed suspension wei~ht and all fasteners.

Introduction

2

17730-251

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HTB® 400LT for International® Truck Vehicles
FIGURE 2-1 • HTB® 400LT
Lightweight, Non-torque Reactive Rear Air Suspension

HTB® 400LT SPECIFICATIONS 1
40,000 lbs.
810 lbs.
10%
Tandem
55,000 lbs.
120,000 lbs.
9.25"
None
52"

Capacity
Installed Weight2
Off-highway Rating
Axle Configuration
GVW Approval
GCW Approval
Ride Heights
Engine Torque Restrictions
Axle Spacing
Applications3·5
General Freight (Van, Flatbed)
Refrigerated
Car Carrier
Bulk Hauler (Liquid, Dry)
Beverage
Dump 4

Yes
Yes
Yes
Yes
Yes
Yes

Actual product performance may vary depending upon vehicle configuration, operation, service and
other factors. All applications must comply with applicable Hendrickson specifications and must also be
approved by the respective vehicle manufacturer with the vehicle in its original, as-built configuration.
Contact Hendrickson and the respective vehicle manufacturer for approval of additional applications.
2

Installed weight includes suspension components and all fasteners.

3

These are indicative of typical applications. Please contact your dealer or a Hendrickson service representative before using suspension on other applications.

4

Not for rock-body or mobile mix applications.

5

OEM approval required for applications with a lift axle.

U.S. and foreign patents granted and/or pending.
17730-251

3

Product Description

HTB® 400LT for International® Truck Vehicles

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Important Safety Notice
Proper 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 servicing 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 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.

a.

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.

~

A

DANGER

INDICATES AN IMMINENTLY HAZARDOUS SITUATION, WHICH. IF NOT AVOIDED, WILL RESULT IN
SERIOUS INJURY OR DEATH.

A
A

WARNING

INDICATES A POTENTIAL HAZARDOUS SITUATION. WHICH, IF NOT AVOIDED. COULD RESULT IN DEATH
OR SERIOUS INJURY.

CAUTION

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.
Also note that particular service operations may require the use of special tools designed
for specific purposes. These special tools can be found in the Special Tools Section of this
publication.
The torque symbol alerts you to tighten fasteners to a specified torque value. Refer to Torque
Specifications Section of this publication.

Important Safety Notice

4

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HTB® 400LT for International® Truck Vehicles
• SAFETY PRECAUTIONS

A

WARNING

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, LOSS OF VEHICLE CONTROL,
PERSONAL INJURY. OR PROPERTY DAMAGE.
LOOSE OR OVER TORQUED FASTENERS CAN CAUSE COMPONENT DAMAGE, LOSS OF VEHICLE
CONTROL 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 SPECIFICATION LISTED IN THE VEHICLE MANUFACTURER'S SERVICE MANUAL.

A

WARNING

LOAD CAPACITY
ADHERE TO THE PUBLISHED CAPACITY RATINGS FOR THE SUSPENSION.ADD-ON AXLE ATTACHMENTS
AND OTHER LOAD TRANSFERRING DEVICES CAN INCREASE THE SUSPENSION LOAD ABOVE ITS
RATED AND APPROVED CAPACITIES, WHICH CAN RESULT IN COMPONENT DAMAGE AND LOSS OF
VEHICLE CONTROL POSSIBLY CAUSING PERSONAL INJURY OR PROPERTY DAMAGE.

A

WARNING

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, LOSS
OF VEHICLE CONTROL POSSIBLE PERSONAL INJURY OR PROPERTY DAMAGE, AND WILL VOID
WARRANTY. USE ONLY HENDRICKSON AUTHORIZED REPLACEMENT PARTS.

A

WARNING

TORCH/WELDING
DO NOT USE A CUTTING TORCH TO REMOVE ANY ATTACHING FASTENERS. THE USE OF HEAT ON
SUSPENSION COMPONENTS WILL 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.

A

WARNING

U-BOLT CLAMP GROUP CONNECTION
IT IS IMPORTANT THAT THE U-BOLT CLAMP GROUP CONNECTION BE PROPERLY ALIGNED AND HAVE
THE PROPER TIGHTENING TORQUE VALUES MAINTAINED. METAL SURFACES CAN WORK AND WEAR
AGAINST OTHER RELATED CLAMP GROUP COMPONENTS IF NOT PROPERLY ALIGNED OR PROPERLY
TIGHTENED TO MAINTAIN THE PROPER CLAMP FORCE. FAILURE TO DO SO CAN CAUSE PREMATURE
COMPONENT WEAR, POSSIBLE SEPARATION OF THE CLAMP GROUP, CAUSING LOSS OF VEHICLE
CONTROL PROPERTY DAMAGE, OR PERSONAL INJURY.

A

DANGER

LONGITUDINAL TORQUE ROD
THE AIR SPRING TRANSFERS LOAD TO THE FRAME HANGER THROUGH THE LONGITUDINAL TORQUE
ROD. PRIOR TO LONGITUDINAL TORQUE ROD REMOVAL THE SUSPENSION AIR SYSTEM MUST BE
DEFLATED. FAILURE TO DO SO WILL CAUSE THE AIR SPRING TO ROTATE AND/OR SHIFT, RESULTING IN
POSSIBLE DAMAGE TO COMPONENTS AND/OR PERSONAL INJURY.

A

WARNING

TORQUE BOX CLAMP BOLTS
IT IS IMPORTANT THAT THE TORQUE BOX CLAMP CONNECTIONS BE TIGHTENED IN THE PROPER
SEQUENCE AND HAVE THE PROPER TIGHTENING TORQUE VALUES MAINTAINED. FAILURE TO DO SO
CAN RESULT IN THE DEFORMATION OF PARTS, RESULTING IN THE LOSS OF CLAMP FORCE, BOLT
FAILURE, LOSS OF THE AXLE'S ALIGNMENT, LOSS OF VEHICLE CONTROL PROPERTY DAMAGE, OR
PERSONAL INJURY.

17730-251

5

Important Safety Notice

HTB® 400LT for International® Truck Vehicles

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TORQUE BOX AXLE BRACKET SPACER
VEHICLES BUILT AFTER OCTOBER 2007 - EACH AXLE HAS TWO (2) AXLE BRACKETS. EACH AXLE
BRACKET HAS ONE (1) LEFT HAND AND ONE (1) RIGHT HAND BAR PIN CLAMPS AND TWO (2) AXLE
BRACKET SPACERS. BOTH SPACERS MUST BE USED WITH THE BAR PIN CLAMPS. FAILURE TO DO SO
CAN RESULT IN THE DEFORMATION OF PARTS, LOSS OF CLAMP FORCE, BOLT FAILURE, LOSS OF THE
AXLE'S ALIGNMENT, LOSS OF VEHICLE CONTROL PROPERTY DAMAGE, OR PERSONAL INJURY.
VEHICLES BUILT PRIOR TO OCTOBER 2007 - EACH AXLE HAS ONE (1) AXLE BRACKET WITH AN
ADJUSTABLE BAR PIN CLAMP WITH FOUR (4) AXLE BRACKET SPACERS AND ONE (1) AXLE BRACKET
WITH NON-ADJUSTABLE BAR PIN CLAMPS. THE BAR PIN CLAMP PAIRS CAN BE CHANGED FROM
SIDE TO SIDE BUT CAN NOT BE MIXED. ALL FOUR AXLE BRACKET SPACERS MUST BE USED WITH THE
ADJUSTABLE BAR PIN CLAMPS WHICH ARE THINNER THAN THE NON-ADJUSTABLE BAR PIN CLAMPS.
FAILURE TO DO SO CAN RESULT IN THE DEFORMATION OF PARTS, LOSS OF CLAMP FORCE, BOLT
FAILURE, LOSS OF THE AXLE'S ALIGNMENT, LOSS OF VEHICLE CONTROL PROPERTY DAMAGE, OR
PERSONAL INJURY.
MAKE SURE DRAINAGE FEATURE IS NOT OBSTRUCTED WITH DEBRIS. IF SO, CLEAR AREA WITH BRUSH
OR AIR HOSE. FAILURE TO DO SO MAY ALLOW CAVITY TO FILL WITH WATER AND SEEP INTO AXLE
HOUSING THROUGH BREATHER HOLE SIDE.

A

WARNING

A

WARNING

ALUMINUM COMPONENTS
THE HTB 400LT CONTAINS VARIOUS ALUMINUM COMPONENTS. EXERCISE EXTREME CARE WHEN
HANDLING OR PERFORMING MAINTENANCE NEAR OR ON ALUMINUM COMPONENTS. DO NOT USE
A CUTTING TORCH TO REMOVE ANY ATTACHING FASTENERS. THE USE OF HEAT ON SUSPENSION
COMPONENTS WILL ADVERSELY AFFECTTHE STRENGTH OF THESE PARTS.A COMPONENT DAMAGED
INTHIS MANNER CAN RESULT INTHE LOSS OF VEHICLE CONTROL AND POSSIBLE PERSONAL INJURY
OR PROPERTY DAMAGE.
ALUMINUM COMPONENTS WERE DESIGNED TO BE LIGHTWEIGHT OPTIONS WHERE WEIGHT
REDUCTION IS DESIRABLE. THEIR USE SHALL BE CONFINED TO APPLICATIONS WHERE THE RATED
CAPACITY OF THE SUSPENSION WILL NOT BE EXCEEDED. FAILURE TO LIMIT THE ALUMINUM
COMPONENT APPLICATIONS TO RATED CAPACITY CAN RESULT IN FAILURE OF THE COMPONENT AND
LOSS OF VEHICLE CONTROL POSSIBLY CAUSING PERSONAL INJURY OR PROPERTY DAMAGE.
ALUMINUM COMPONENTS SUCH AS, TORQUE RODS, TORQUE ROD BAR PIN, CROSS MEMBER CLAMP
BLOCKS.AIR SPRING BRACKETS, FR,ll;ME HANGER, CROSS MEMBER GUSSETS, TOP PAD, ETC., CAN BE
DAMAGED WITH PROLONGED EXPOSURE TO SALT, OR ACID. CONTINUED EXPOSURE CAN RESULT IN
A FAILURE OF THESE PARTS AND LOSS OF VEHICLE CONTROL POSSIBLY CAUSING PERSONAL INJURY
OR PROPERTY DAMAGE.
ALUMINUM COMPONENTS CAN ALSO BE DAMAGED BY CONTACT WITH HARD OBJECTS WHICH GOUGE
THESE PARTS.THESE CONDITIONS COULD RESULT IN AFAILURE OF THESE PARTS WHICH CAN RESULT IN
THE LOSS OF VEHICLE CONTROL AND POSSIBLE PERSONAL INJURY OR PROPERTY DAMAGE.

A

WARNING

AIR SPRINGS
AIR SPRING ASSEMBLIES MUST BE COMPLETELY DEFLATED PRIOR TO LOOSENING ANY CLAMP
GROUP HARDWARE, OR OTHERWISE PERFORMING ANY MAINTENANCE, SERVICE OR REPAIR OF
THE SUSPENSION SYSTEM. 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