SB-17720-238-A Service Bulletin/Repair Instructions

HJ TECHNICAL

®

PROCEDURE

PRIMAAX® EX • FIREMAAX® EX/

PRIMAAX® • FIREMAAX®Series

Heavy-duty Rear Air Suspension

PRIMAAX EX
SUBJECT: Service Instructions

LIT NO: 17730-238

REVISION : E

DATE: December 2014
Section 1
Introduction........ .. .... . . ............. 2
Section 8
Section 2
Product Description ...................... 2
Section 3
Important Safety Notice ..... ....... ...... 5
Section 4
Parts Lists ............................. 10
Height Control Vo Ive .... . . . ........... . .... 58
Section 5
Special Tools ................. . . . ...... . 28
Shock Absorber .............. ... . .. ...... 59
Section 6
Preventive Maintenance .......... ... ... . 30
Transverse Torque Rod .. ... ................ 60
Component Replacement ................ 54

Fasteners ............. . . ..... ........... 54

Air Spring ...... . . ....................... 54

Air Spring I Upper Air Spring Brocket ........... 56
Longitudinal Torque Rod .... .......... . . . ... 61
Hendrickson Recommended Preventive

Maintenance Intervals ................ 30
Torque Rod Bushing .............. . . . ...... 63
Component Inspection ..................... 32
Support Beam Assembly ond Cross Tube ... .... 64
U-boll locknuts ........................... 33
U-beom Assembly .............. ... ....... 65
Pivot Bushing and D-Pin Bushing Inspection . .... 34
D-pin Bushing .............. .. . ... ....... 69
Longitudinol and Tronsverse Torque Rods ....... 36
QUIK-ALIGN Pivot Bushing - Using o Shop Press .. 74
Air Fitting Inspection.............. ........ . 38
QUIK-ALIGN Pivot Bushing - Using Tool

No. 66086-203L .. .... . . ........... .. 75
Shock Absorber Inspection ............ . ..... 38
Top Pod .... .... ..... .. ................. 76

Section 7
Al ignment & Adjustments ......... .... ... 40
Bottom Cop and Axle Spacer (If Equipped) ...... 79
Ride Height ............................. 40
S-Com Support Brocket (If Equipped) .......... 82
Single Height Control Valve ................. 40
Axle Stops ........... . .................. 82
Dual Heigh! Control Valves .... .............. 43
Frome Hanger ...... .. . .......... ... . .... 83
Lateral Alignment ............... . ........ 45

Axle Pinion Angle ............. ..... ...... 45
Aftermorket Duol Height Control Valves ....... . . 87

Section 9
Plumbing Diagrams..... . •...... ...... .. 89
Drive Axle Alignmenl Inspection Procedure ...... 46

Alignment Adjustment Instructions ..... . . . .... 47

Pinion Angle Adjustment .... .. .. ......... .. 51
Section 1O Torque Specifications .. ... . . ......... ... 90

Section 11 Troubleshooting Guide . . . . . . . . . . . . . . . . 102
~HENDRICKSON
ftfe ~O?H;(?~s 0// l/s®
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PRIMAAX® EX • FIREMAAX® EX
SECTION l
Introduction

This publication is intended to acquaint and assist maintenance personnel in the preventive mointenonce, service. repair, and rebuild of PRIMAAX EX I FIREMAAX EX • PRIMAAX I

FIRE MAAX suspension systems.

Refer to our Hendrickson website for other vehicle manufacturer specific PRIMAAX EX I PRIMAAX

suspension literature:

•
NOTE
Kenworth (17730-263) , Volvo (17730-254), Mock (17730-279). International Truck

(17730-283), ond Caterpiller (17730-284)
Use only ffil Hendrickson Genuine 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 ports lists. safety information, product specifications, features, proper

maintenance, service, repair and rebui ld instructions for the PRIMAAX EX I FIREMAAX EX •

PRIMAAX I FIREMAAX suspensions.

Hendrickson reserves the right to make changes and improvements to its products and

publications at any time . Contoct Hendrickson Tech Services for information on the latest version of this manual at 1-866-755-5968 (toll-free U.S. and Canada), 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

PRIMAAX EX
FIREMAAXEX
MAAXimize the performance of vocational and heavy-haul

vehicles with a suspension eng ineered specifically for

demanding on- and off- rood conditions. With 100 yeors

of robust suspension design, Hendrickson delivers another

premium suspension with PRIMAAX EX. Rugged, dependable and extensively tested in challenging applications,

PRIMAAX EX paves a new rood for suspension technology.

Drivers. cargo and vehicles are major investments that

require protection. PRIMAAX EXadjusts to variations in load

and road cond itions for optimal ride and performance.

This low-maintenance design delivers greater stability for

improved control on and off the job site.
The FIREMAAX EX heavy-duty rear air suspension provides

a package of benefits previously unavailable in any one

emergency vehicle air suspension. Its outstanding ride

produces superior driver and passenger comfort while

helping to protect critical. life-saving equipment and

costly electronic components from excessive vibration

and rood shock. The suspension geometry and air spring

design work together to produce low natural frequencies resulting in a premium ride. FIRE MAAX EX provides

enhanced stability for demanding fire I rescue vehicle

applications. delivering more than twice the roll stiffness

compared to other air suspensions.
lnlroduction
2
17730.238
'H

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PRIMAAX EX®• FIREMAAX EX®
PRIMAAX9 EX 26215221782

FIREMAAX• EX 2721542

8¥2''-10" Ride Height
PRIMAAX9 EX 23214621692

FIREMAAX* EX 2421482

8¥2''-1 O" Ride Height
9
PRIMAAX EX 23214621692

FIREMAAX' EX 2421482

12¥2'', 143/s'', 15¥2'' Ride Height
17730-238
•
Unique suspension geometry - Optimized configuration significantly controls suspension

windup and corresponding frame rise. while increasing roll stiffness and reducing roll steer.
•
Easy axle alignment - Hendrickson's proven QUIK-ALIGN®axle alignment system helps

save time and money and offers a fast method lo ensure proper alignment for improved

lire life.
•
D-pin axle con nection and clamp group - Reduces stress input lo the axle housing by

transferring the torsional loads to the integrated stabilizer system. which helps extend axle

and join! service life.
•
Large volume air springs - Reduce noise. vibration and harshness to cab, chassis and body

equipment far reduced total vehicle maintenance; new integrated pistons and spacers provide

a more robust beam connection while lifting and supporting the load with less air pressure.
•
Frame Hanger - New. more robust design to meet a variety of grueling vocational and

severe-duty applications.
•
Structural beam end jo int - Maintenance-free connection with cross brace reduces

downtime for improved productivity.
•
Cost structural beams - Redesigned beams uti lize premium materia ls to improve

durability mor than 350 percent (based on lab testing).
•
Heavy-duty shock absorbers - Positioned and tuned for optimum damping characteristics

and protect air springs from over-extension.
•
Torque Rods - Three-rod configuration reduces axle stress, welding and complexity .

Optimized configuration helps improve handling and roll stiffness for expanded applications.

Premium retained rubber bushings for increased service life and resistance to walkout.

Designed for optimum clearance and articulation. Alternative rods available for disc broke use.
3
Product Desc11pllon
1-f

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PRIMAAX® EX• FIREMAAX® EX

PRIMAAX EX SPECIFICATIONS

Roting

Installed Weight'

Axle Configuration
PAX 232
PAX 262
PAX 462
23.000 lbs.

542 lbs.
26.000 lbs.

651 lbs.
46.000 lbs.

1,078 lbs.
PAX 522

52.000 lbs.

1,292 lbs.
Single
Single
Tandem
Tandem
Tridem
Tridem

See Axle

Manufacturer

Recommendation
99,000 lbs.

8.5"

10.5"
PAX 692

69,000 lbs.

1,629 lbs.
GCW Approval'
95,000 lbs.
142.000 lbs.
190.000 lbs.
245.000 lbs.
See Axle

Manufacturer

Recommendation
Site Travel Roting 3
30.000 lbs.

8"

10.75"
33,000 lbs.

8"

10.5"
60.000 lbs.

8"

10.75"
66,000 lbs.

8"

10.5"
90.000 lbs.

8"

10.75"
Axle Travel'

Ground Clearance
Lift Axles
PAX 782

78,000 lbs.

1.931 lbs.
Approved
Approved
Approved
Approved
Approved
Approved
Ride Heights'
8.5" - 10.5''

12.5" -15.5"
8.5" -1 0.5''

12.5" - 15.5"
8.5" - 10.5''

12.5" - 15.5"
8.5" -10.5"

12.5" -15.5"
Axle Spacing
N/A
N/A
52"· 72.5"
54"· 72.5"
8.5" -10.5"

12.5" -15.5"

52"- 60"
8.5" -10.5"

12.5" - 15.5"

54"- 60"
PRIMAAX EX is approved for vocational and heavy-haul vehicle opplicot1ons including, but not limited to: truck. tractor. dump, front and rear discharge mixers.

logging, crone mounted, platform. fire I rescue. specialty and vehicles equipped with outriggers. Some vehicle configurations, such as vehicles equipped with

outriggers. may require alternate suspension air valving. 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 specifications the respective vehicle manufacturer for approval of odditionol opplicolions.

l . Installed weight includes complete suspension. torque rods. axle and frame brackets and oil hardware.Published weight is based on o standard PRIMAAX EX

suspension using l 0.0 inch ride height. Other configurations may vary.

2. Contact Hendrickson for applications that may exceed GWI I GCW approval ratings.

3. Site travel roting - operators using vehicles equipped with lifloble pusher or tog axles must not exceed published ratings. Ratings ore limited to no more

than five percent of vehic le operation ot o speed not to exceed five mph. Liftoble pusher or tog axles should be raised (or unloaded) to improve vehicle maneuverability in off-rood use or when vehicle is empty. Site lrovel ratings ore consistent with published axle manufacturer's limitations.Axle ond suspension

site travel specifications must not be exceeded.

4. Suspension orticulot1on moy exceed vehicle's capability and moy be limited by vehicle manufacturer; vehicle manufacturer installed axle stop may restrict

suspensions articulation

5. Contact Hendrickson for availability of beam lengths.

6. Shock absorbers ore required in tractor and logging applications. Ride and traction may be improved in other applications with shock absorbers. Ride perfor·

monce con be subjective and may be dependent on many factors beyond the suspension design, such os cob suspension. rood conditions, body I auxiliary

equipment. frame specif1cotions. etc.Contact Hendrickson on your truck manufacturer I dealer for further information.
FIREMAAX EX SPECIFICATIONS

FMX 242

24.000 lbs.

550 lbs.
FMX 272

27.000 lbs.

658 lbs.
FMX 312

31 .000 lbs.

665 lbs.
FMX 482

48,000 lbs.

1.090 lbs.
FMX 542

54.000 lbs.

1.305 lbs.
FMX 622

62.000 lbs.

1320 lbs.
Axle Configuration
Single
Single
Single
Tandem
Tandem
Tandem
Axle Travel'
8"

10.75"
8"

10.5"
8"

10.5"
8"

10.75"
8"

10.5"
8"

l 0.5''
8.5" to 15.5"
8.5" to 12.5"
8.5",10",13"
8.5" to 15.5"
8.5" to 12.5"
8.5",10",13"
Roting

Installed Weight'
Ground Cleoronce3

Ride Heights'
None
None
None
None
None
None
Axle Spacing
Engine Torque Restrictions
N/A
N/A
N/A
52"- 72.5"
54"- 72.5"
54"· 72.5"
Disc Broke Compatibility
Yes
Yes
No
Yes
Yes
No
• FIREMAAX EX capacity ratings apply to fire and rescue market only.

• FIREMAAX EX may be referred to os PRIMAAX EX by some OEMs.

• All opplicollon must comply with applicable Hendrickson specifications and must also be approved by the respective vehicle manufacturer for approval of

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