{ffiTECHNICAL
PROCEDURE
HN® Series Rear Suspension
SUBJECT: Service Instructions
LIT NO: 17730-227
DATE: August 2013
REVISION: C

Section l Introduction . ........................ 2

Section 8 Component Replacement ............ 31

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

Fasteners . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Section 3 Important Safety Notice . .............. 4

Saddle ............................. 31

Section 4 Special Tools ........................ 7
Section 5 Parts lists .......................... 8
Section 6 Preventive Maintenance ............. 16

Auxiliary Spring ...................... 33
Rebound Strap ....................... 34
Bolster Spring ........................ 35

Vee Bracket ......................... 36

Hendrickson Recommended Preventive
Maintenance Intervals ............... 16

Shock Absorber ...................... 37

Component Inspection ................. l 7

Equalizing Beam ..................... 38

Axle Bracket ......................... 18

Bar Pin End Bushing ................... 43

Equalizing Beam End Connection ......... 18

Longitudinal Torque Rod ................ 46

Bar Pin End Bushing .................. 20

Transverse Torque Rod ................. 46

Bar Pin Shim ........................ 20

Torque Rod Bushing ................... 47

Longitudinal and Transverse Torque Rod .... 21

Section 9 Troubleshooting Guide .............. 49

Bolster Spring ........................ 21

Section 10 Torque Specifications ............... 50

Auxiliary Spring ...................... 22
Shock Absorber ...................... 23
Rebound Strap ....................... 24

Section 7 Alignment & Adjustments . ........... 25
Drive Axle Alignment Inspection Procedure .. 25
Bar Pin Alignment ..................... 26
Bar Pin Alignment Shim ................ 28
. Auxiliary Spring Shim Evaluation .......... 29
Auxiliary Spring Shim Adjustment ......... 30

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HN® Series
SECTION 1

Introduction
This publication is intended to acquaint and assist maintenance personnel in the preventive maintenance, service, repair and rebuild of the HN® Series suspension system. Refer to
Hendrickson Technical Publication 17730-285 for Fire/Rescue vehicles.

NOTE

Use only [HJ Hendrickson parts for servicing this suspension system, see the Parts List Section of
this publication for component replacement parts.
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 and rebuild instructions for the HN Series 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 on line
at www.hendrickson-intl.com.

SECTION 2

Product Description
The HN 402/462/522 suspension systems uses VariRate® spring system which delivers a combination of superior stability, articulation and ride. Proven with extensive lab & vehicle durability
testing, suspension weight has been reduced through innovative suspension design.
The vehicle manufacturer determines the vehicle capacity. To help determine the vehicle capacity, use the VIN number and contact the vehicle manufacturer. See the Parts List Section of this
publication to assist with identifying replacement parts.
FIGURE 2-1 HN 462

Equalizing Beam
Bolster Springs
Beam End Bar Pin Bushing

Introduction

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17730-227

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HN® Series
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Auxiliary springs - Engages while loaded to provide added stability when dumping or
maneuvering.
Bar pin end connection - Rugged axle connection extends bushing life and allows easy
axle alignment capability for accurate wheel tracking, improved tire life and serviceability.
Equalizing beam - Formed and robotically-welded equalizing beam design eliminates
center bushings and lubrication requirements - significantly reducing scheduled maintenance. It provides a narrow profile for weight savings; distributes load equally between both
axles for improved traction; lowers the center of gravity to increase stability and establishes
a solid axle connection for improved handling.
Rubber bolster springs - Lightweight, diagonally mounted rubber bolster springs deliver
a smooth ride and outstanding articulation in empty or lightly loaded conditions. The wide
spring centers enhance stability and eliminate need for cross tube.
Saddle and frame brackets - Weight-saving, high-strength design increases carrying
capacity and durability.
Shock absorbers - Integrated design reduces axle hop and enhances ride quality.
ULTRA RODS® - Heavy duty forgings reduce weight; yet provide improved durability over
conventional rods. Transverse rods ensure maximum lateral axle control and straight line
suspension stability and Longitudinal rods are engineered to optimize resistance to wind
up during acceleration and braking hence improve cornering by controlling lateral forces.
ULTRA ROD's unique bonded bushing greatly increases its service life. By eliminating the
outer metal sleeve, Hendrickson made re-bushing faster and easier.
VariRate® Spring System - Delivers a combination of superior stability, articulation and
ride. System can be tailored to meet the specific needs of unique vehicle applications

HN® SERIES SPECIFICATIONS
Installed Weight1
(54 inch axle spacing)
Suspension Roting
GVW Approvol2
GCW Approval
Site Travel Rating 3
Diagonal Articulotion 4
Lift Axles 3
Axle Spacing
Wheel Bose Restriction

HN 402
935 lbs.

HN 462
948 lbs.

HN 522
955 lbs.

40,000 lbs.
73,000 lbs.

46,000 lbs.
80,000 lbs.

80,000 lbs.

160,000 lbs.
55,000 lbs.
17"
Approved
52", 54", 60", 72.5"
None

190,000 lbs.
60,000 lbs.
17"
Approved
54", 60", 72.5"
None

245,000 lbs.
65,000 lbs.
17"
Approved
54",60"
None

52,000 lbs.

HN Series suspensions ore intended for a wide range of applications*, including dump, refuse, mixer and logging . If you
hove any questions, contact Hendrickson or your local truck dealer.
1 Installed weight includes complete suspension, torque rods, axle brackets, shock absorbers and frame brackets.
2 Contact Hendrickson for applications that may exceed GVW approval ratings.
3 Site Travel Roting - Operators using vehicles equipped with liftoble pusher or tog axles must not exceed published ratings. Ratings ore limited to no more than 5 percent of vehicle operation at speed not to exceed 5 mph. Liftoble pusher or
tog axles should only be raised (or unloaded) to improve vehicle maneuverability in off-rood use or when vehicle is empty.
Site trove ratings ore consistent with published axle manufacturer's limitations. Axle and suspension site travel specifications must not be exceeded.
4 Suspension articulation may exceed vehicle's capability and may be limited by vehicle manufacturer; vehicle manufacturer installed axle stops may restrict suspension's articulation.
* Not approved for tractor applications.

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Product Description

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HN® Series
SECTION 3

Important Safety Notice
Proper maintenance, service and repair is important to 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.
The warnings and cautions should be read carefully to help prevent personal injury and to
assure that proper methods are used. Improper 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 that 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.
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.

m
A

A
A

DANGER

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

WARNING

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

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

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HN® Series
SAFETY PRECAUTIONS

A

WARNING

A

WARNING

A

WARNING

A

WARNING

A

WARNING

A

CAUTION

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
VALUES AT ALL TIMES. CHECK TORQUE VALUES ON A REGULAR BASIS AS SPECIFIED USING A
TORQUE WRENCH THAT IS REGULARLY CALIBRATED. 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.

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.

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 ANY
APPLICABLE WARRANTIES. USE ONLY HENDRICKSON AUTHORIZED REPLACEMENT PARTS.

TORCH/WELDING
DO NOT USE A CUTTING TORCH TO REMOVE ANY FASTENERS. THE USE OF HEAT ON SUSPENSION
COMPONENTS WILL ADVERSELY AFFECTTHE STRENGTH OFTHESE PARTS.A COMPONENT DAMAGED
IN THIS MANNER CAN RESULT IN THE LOSS OF VEHICLE CONTROL AND POSSIBLE PERSONAL INJURY
OR PROPERTY DAMAGE.
EXERCISE EXTREME CARE WHEN HANDLING OR PERFORMING MAINTENANCE IN THE AREA OF THE
EQUALIZING BEAM. DO NOT CONNECT ARC WELDING GROUND LINE TO THE EQUALIZING BEAM. DO
NOT STRIKE AN ARC WITH THE ELECTRODE ON THE EQUALIZING BEAM AND AXLE. DO NOT USE HEAT
NEAR THE EQUALIZING BEAM ASSEMBLY. DO NOT NICK OR GOUGE THE EQUALIZING BEAM. SUCH
IMPROPER ACTIONS CAN DAMAGE THE EQUALIZING BEAM ASSEMBLY, AND CAN CAUSE LOSS OF
VEHICLE CONTROL AND POSSIBLE PERSONAL INJURY OR PROPERTY DAMAGE.

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

PROCEDURES AND TOOLS
ATECHNICIAN USING A SERVICE PROCEDURE OR TOOL WHICH 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 WILL ASSUME ALL RISKS OF CONSEQUENTIAL
PERSONAL INJURY OR DAMAGE TO EQUIPMENT INVOLVED.

17730-227

SUPPORTTHE VEHICLE PRIOR TO SERVICING
DO NOT AT ANYTIME WORK AROUND OR UNDER AVEHICLE SUPPORTED ONLY ON LIFTING DEVICES.
THE VEHICLE MUST BE SECURELY CHOCKED AND SUPPORTED ON RIGID STANDS OF SUFFICIENT
STRENGTH BEFORE WORK MAY COMMENCE.

5

Important Safety Notice

HN® Series

A

WARNING

A

WARNING

Important Safety Notice

TRANSVERSE RODS
THE HN 402/462/522 SUSPENSION INCORPORATE TRANSVERSE RODS FOR VEHICLE STABILITY. IF
THESE COMPONENTS ARE DISCONNECTED OR ARE NON-FUNCTIONAL, THE VEHICLE SHOULD NOT
BE OPERATED. FAILURE TO DO SO CAN RESULT IN ADVERSE VEHICLE HANDLING, LOSS OF VEHICLE
CONTROL, POSSIBLE TIRE CONTACT WITH THE FRAME, PREMATURE COMPONENT DAMAGE, OR
SEVERE PERSONAL INJURY.

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:
l. WEAR PROPER EYE PROTECTION.
2. WEAR CLOTHING THAT PROTECTS YOUR SKIN.
3. WORK IN AWELL-VENTILATED AREA.
4. DO NOT USE GASOLINE OR SOLVENTS THAT CONTAIN GASOLINE. GASOLINE CAN EXPLODE.
5. HOT SOLUTION TANKS OR ALKALINE SOLUTIONS MUST BE USED CORRECTLY. FOLLOW THE
MANUFACTURER'S RECOMMENDED INSTRUCTIONS AND GUIDELINES CAREFULLYTO 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 WARRANTY.

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HN® Series

SECTION 4

Special Tools
These shop made tools are designed to remove and install rubber mounted torque rod bushings. The shop made tool set will
service both the straddle mount and the tapered stud bushings. Bushing tools are made from cold rolled steel or equivalent.
Drawings are for reference only. Hendrickson does not supply these tools.

BAR PIN END BUSHING TOOL
Push Out Tool

TORQUE ROD BUSHING TOOLS
Receiving Tool
Push OutTool

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04.25"

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BAR PIN ADAPTER SET TOOL
OTCTool No. 1757
Servicing bar pin end bushings used on Hendrickson HN
equalizing beam suspensions requires the use of special
tooling.
OTC's No. 1757 adapter set is used with the equalizing beam
removed from the truck, and in conjunction with OTC No.
51100 press plate and a 100 ton hydraulic shop press.
To order, contact OTC, 507 .455. 7000 or
visit: www.otctools.com for an OTC distributor.

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Special Tools

SECTION 5

Parts Lists
HN® 402/462/522 -Vehicles built after 11/00

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Parts Lists

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