Hendrickson ULTIMAAX 58K, ULTIMAAX 54K, ULTIMAAX 63K Technical Procedure

TABLE OF CONTENTS

ULTIMAAX® Rear Suspension
for Fire and Rescue Vehicles

SUBJECT: Service Instructions
LIT NO: 17730-299
DATE: July 2018 REVISION: B

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

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

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

Section 4 Special Tools .......................8

Section 5 Parts List ..........................10

Section 6 Preventive Maintenance

Hendrickson Recommended

Inspection Intervals ................13

Component Inspection ................13

Center Bushings .....................14

Equalizing Beam End Connection ........15

Bar Pin End Bushings .................18

Bar Pin Shims .......................18

Beam End Axle Brackets ...............19

Frame Hanger Assembly ...............20

Shear springs .......................20

Progressive Load Springs (PLS) ..........21

Saddle Connection ...................22

Cross Tube. . . . . . . . . . . . . . . . . . . . . . . . . . 23

Section 7 Alignment & Adjustments

Drive Axle Pinion Angle ................27

Drive Axle Alignment ..................27

Axle Lateral Alignment .................29

Bar Pin Alignment ....................29

Section 8 Component Replacement

Fasteners ..........................32

Shock Absorber ......................32

Shear Spring / Frame Hanger Assembly /

Saddle Assembly ..................33

Progressive Load Spring (PLS) ...........38

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

Equalizing Beam Center Bushing .........41

Bar Pin Style End Bushings .............44

Adapter Style End Bushings .............46

Cross Tube. . . . . . . . . . . . . . . . . . . . . . . . . . 50

Torque Rods ........................51

Torque Rod Bushings ..................52

Section 9 Troubleshooting Guide ..............57

Torque Rods ........................24

Shock Absorbers .....................25

Section 10 Torque Specications ...............58

ULTIMAAX® for Fire and Rescue Vehicles

SECTION 1

Introduction

This publication is intended to acquaint and assist maintenance personnel in the preventive
maintenance, service, and repair of the ULTIMAAX
Fire and Rescue Vehicles.

NOTE Use only

It is important to read and understand the entire Technical Procedure publication prior to
performing any maintenance, service, or repair of this product. The information in this publica­tion contains parts lists, safety information, product specifications, features, proper maintenance,
service, and repair instructions for ULTIMAAX suspensions.

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: [e-mail].

The latest revision of this publication is available online at www.hendrickson-intl.com.

Hendrickson Genuine parts for servicing this suspension system.

SECTION 2

Product Description

ULTIMAAX is an advanced severe-duty rear rubber suspension designed specifically for fire and
rescue applications to balance outstanding durability, empty ride quality, loaded stability and
mobility. Through its unique design, the system offers premium ride quality in both empty and
loaded conditions, with increasing stability as the load increases.

®

Rear Rubber Suspension System for applicable

■

Equalizing beam — Formed and robotically welded to provide a narrow profile for weight
savings. Distributes load equally between axles to improve maneuverability, stability and
handling. Increases ground clearance with flat bottom design. Lowers the center of gravity to
increase stability.

■

Saddle — Triangular geometry provides structure and durability. Weight efficient design
helps to increase payload, while offering a considerable weight savings versus competitive
suspensions.

■

Frame hangers — Optimized design to balance durability and weight savings. Fabricated to
offer flexibility with multiple truck configurations.

■

Rubber shear springs — Primary springs in unloaded condition, providing superb ride quality.
React to longitudinal loads during braking and accelerating for minimal displacement.

■

Progressive load springs — Designed to balance empty ride quality and loaded stability.
Stiffness of progressive load spring increases as load increases, providing a unique balance
of empty ride quality and loaded stability.

■

Longitudinal torque rods — Engineered to optimize resistance to axle wind-up during accel­eration and braking.

■

Transverse torque rods — Heavy-duty transverse torque rods ensure maximum lateral axle
control and straight line suspension stability.

2 17730-299

FIGURE 2-1

ULTIMAAX® for Fire and Rescue Vehicles

54K•58K Capacity

9½"•10"•10¼"•11½" Ride Height

63K Capacity

10"•10½" Ride Height

ULTIMAAX® SPECIFICATIONS

54K 58K 63K

Suspension Rating 54,000 lbs (24,494 kg) 58,000 lbs (26,308 kg) 63,000 lbs (28,576 kg)

Diagonal Articulation

Ride Heights 9½"•10"•10¼"•11½" (241 mm, 254 mm, 260 mm, 292 mm) 10", 10½" (254 mm, 267 mm)

Axle Spacing

Hendrickson approves the use of ULTIMAAX in fire / rescue applications. All such 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.

1. Suspension articulation may exceed vehicle’s capability and may be limited by vehicle manufacturer; vehicle manufacturer installed axle
stops may restrict suspension’s articulation.

2. Contact Hendrickson for availability of additional beam lengths.

For additional details regarding specifications, applications, capacities, operating service and maintenance instructions, refer to applicable
Hendrickson technical literature (available at www.hendrickson-intl.com) or contact Hendrickson at 1-866-768-5968.

Actual product performance may vary depending upon vehicle configuration, operation, service and other factors.

U.S. and foreign patents granted and / or pending.

1

2

54" (1,372 mm) 54", 56" (1,372 mm, 1,422, mm)

17½" (445 mm)

17730-299 3

ULTIMAAX® for Fire and Rescue Vehicles

SECTION 3

Important Safety Notice

Proper maintenance, service and repair are 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.

This technical publication 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 the vehicle unsafe in operation, or void the 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.

This is the safety alert symbol. It is used to alert you to potential personal injury haz-

ards. 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.

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 the fasteners to a specific torque value. See Torque

Specifications Section of this publication.

4 17730-299

■

SAFETY PRECAUTIONS

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 SPECIFICATION LISTED IN THE VEHICLE MANUFACTURER’S SERVICE MANUAL.

TORCH/WELDING

DO NOT USE A CUTTING TORCH TO REMOVE ANY FASTENERS OR BUSHINGS. 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 ADVERSE VEHICLE HANDLING 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 CAUSE ADVERSE VEHICLE
HANDLING AND POSSIBLE PERSONAL INJURY OR PROPERTY DAMAGE.

ULTIMAAX® for Fire and Rescue Vehicles

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 ADVERSE VEHICLE
HANDLING, POSSIBLY CAUSING PERSONAL INJURY OR PROPERTY DAMAGE.

MODIFYING COMPONENTS

DO NOT MODIFY OR REWORK PARTS WITHOUT AUTHORIZATION FROM HENDRICKSON. DO NOT
USE SUBSTITUTE OR 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, AND POSSIBLE PERSONAL INJURY OR PROPERTY DAMAGE AND WILL
VOID WARRANTY. USE ONLY HENDRICKSON AUTHORIZED REPLACEMENT PARTS.

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

A TECHNICIAN 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.

17730-299 5

ULTIMAAX® for Fire and Rescue Vehicles

SUPPORT THE VEHICLE PRIOR TO SERVICING

PLACE THE VEHICLE ON A LEVEL FLOOR AND CHOCK THE WHEELS TO PREVENT THE VEHICLE FROM
MOVING OR ROLLING. DO NOT WORK AROUND OR UNDER A RAISED VEHICLE SUPPORTED BY ONLY
A FLOOR JACK OR OTHER LIFTING DEVICE. ALWAYS SUPPORT A RAISED VEHICLE WITH RIGID SAFETY
STANDS. FAILURE TO DO SO CAN CAUSE SERIOUS PERSONAL INJURY OR DAMAGE TO EQUIPMENT.

IMPROPER JACKING METHOD

IMPROPER JACKING METHODS CAN CAUSE STRUCTURAL DAMAGE WHICH CAN CAUSE ADVERSE
VEHICLE HANDLING, PROPERTY DAMAGE OR SEVERE PERSONAL INJURY AND WILL VOID
HENDRICKSON’S WARRANTY.

■

DO NOT USE THE SUSPENSION CROSS TUBE AS A JACKING POINT, SEE FIGURE 3-1, REFER TO
VEHICLE MANUFACTURER FOR PROPER JACKING INSTRUCTIONS.

■

ACCEPTABLE LIFTING POINTS FOR A VEHICLE AT THE RATED LOAD INCLUDE BUT ARE NOT
LIMITED TO: THE AXLE, EQUALIZING BEAM, AND THE VEHICLE FRAME RAIL. REFER TO THE VEHICLE
MANUFACTURER FOR PROPER JACKING INSTRUCTIONS.

FIGURE 3-1

63K ShownULTIMAAX

Center Bushing

greaseDO NOT

Equalizing

SADDLE CONNECTION

A SADDLE ASSEMBLY IS ATTACHED TO THE CENTER BUSHING OF EACH EQUALIZING BEAM WITH TWO
(2) SADDLE CAPS. EACH SADDLE CAP USES TWO (2) BOLTS TO CLAMP THE CENTER BUSHING INNER
METAL TO THE SADDLE. EACH SADDLE CAP MUST BE INSTALLED SO THAT THERE IS AN EVEN GAP
BETWEEN THE SADDLE CAP AND THE BASE OF THE SADDLE LEGS AS SHOWN IN FIGURE 3-2. IF EACH
SADDLE CAP IS NOT INSTALLED EVENLY, THE SADDLE LEGS COULD BECOME DEFORMED, RESULTING
IN BENT BOLTS OR DAMAGED SADDLES.

FIGURE 3-2

Beam

Cross Tube

grease or

DO NOT

use as a jacking point

6 17730-299

TORQUE ROD ASSEMBLY

THE ULTIMAAX SUSPENSION INCORPORATES LONGITUDINAL AND TRANSVERSE TORQUE 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
AND POSSIBLE TIRE CONTACT WITH THE FRAME OR THE SUSPENSION.

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. WEAR PROPER EYE PROTECTION.

2. WEAR CLOTHING THAT PROTECTS YOUR SKIN.

3. WORK IN A WELL-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 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 WARRANTY.

ULTIMAAX® for Fire and Rescue Vehicles

17730-299 7

ULTIMAAX® for Fire and Rescue Vehicles

SECTION 4

Special Tools

SADDLE TOOLS

DISASSEMBLY TOOL

Hendrickson Part No. 66086-113L

CENTER BUSHING TOOLS

RECEIVING TOOL

Hendrickson Part No. 66086-112

ASSEMBLY TOOL

Hendrickson Part No. 66086-108L

INSTALLATION TOOL

Hendrickson Part No. 66086-107

REMOVAL TOOL

Hendrickson Part No. 66086-110

BAR PIN STYLE END BUSHING TOOLS – 54K • 58K

RECEIVING TOOL

Hendrickson Part No. 66086-111

INSTALLATION TOOL

Hendrickson Part No. 66086-106

ADAPTER STYLE END BUSHING TOOLS – 63K

End Bushing

Removal / Replacement Adapter

OTC Part Number 208350

Center Bushing

Removal / Replacement Adapter

OTC Part Number 28541

Not Needed for this publication

Clamp
OTC Part Number 208349

REMOVAL TOOL

Hendrickson Part No. 66086-109

Hendrickson Part No. 66086-101

OTC Part No. 1763

Visit otctools.com

8 17730-299

ULTIMAAX® for Fire and Rescue Vehicles

TORQUE ROD BUSHING TOOLS

These shop made tools are made from cold rolled steel or equivalent. The drawings are
for reference only, Hendrickson does not supply these tools.

RECEIVING TOOL INSTALLATION / REMOVAL TOOL ULTRA ROD PLUS FUNNEL TOOL

Hendrickson Part No. 66086-000L

17730-299 9

ULTIMAAX® for Fire and Rescue Vehicles

SECTION 5

Parts List

■

54K – Rosenbauer 9½" Ride Height • KME 10" Ride Height

■

58K – Seagrave 9½", 10¼" and 11½" Ride Height

■

63K – Rosenbauer 10½" Ride Height, KME 10" Ride Height

11

15

13

14

(if equipped)

17

18

16

12

16

23
22

17

23

22

15

16

13

14 (if equipped)

19

16

25

27

1

2

20

21

24

26

10

4

7

6

6

3

5

63K Beam End Conguration

24

8

9

10 17730-299

ULTIMAAX® for Fire and Rescue Vehicles

VEHICLE
KEY NO. PART NO. DESCRIPTION QTY.

1 Equalizing Beam Assembly with Shock Bracket 2
78489-540 54K - Rosenbauer, KME; 58K - Seagrave,

Includes Key Nos. 2-3
78634-540 63K - KME, Includes Key Nos. 2, 8
78634-560 63K - Rosenbauer, Includes Key Nos. 2, 8
Equalizing Beam Bushing Service Kits

• 54K / 58K Bar Pin Style
60961-755 Center and End Bushing, One Beam, Includes

Key No. 2-3,5-7, 21-23
60961-752 End Bushing, One Wheel End, Includes

Key Nos. 3-7
End Bushing Fasteners, Includes Key Nos. 5-7

56659-001 Tandem
56659-005 One Beam

34013-104 One Wheel End

• 63K Through Bolt Style
34013-052 End Bushing and Adapter Service Kit,

One Wheel End, Includes Key Nos. 8-9
2 Center Bushing 2
3 *Bar Pin End Bushing Assembly, 54K/58K,

Includes Key No. 4a
4 Bar Pin Shim 8
a 50130-000 0.19" / 0.19" Standard
b 50131-000 0.25" / 0.12" Optional
c 57026-000 0.375" Optional at shim
5 *1"-8 UNC x 6" Bolt 8
6 *1" Hardened Washer 16
7 *1"-8 UNC Locknut 8
8 *End Bushing, 63K 4
9 21140-007 End Bushing Adapter Assembly, 63K 4
60961-759 Cross Tube Service Kit, Includes Key No. 10

and Weldable Loose Plug (Not Shown)
10 44642-008 Cross Tube - 1140 mm 1
11 Frame Hanger 2

• 34" Width - 54K/63K KME
78726-001 10" Ride Height

• 341⁄8" Width - 58K Seagrave
78592-002 9½" and 10¼" Ride Height
78592-005 11½" Ride Height

• 35" Width - Rosenbauer
70912-005 10½" Ride Height, 63K
70912-206 9½" Ride Height, 54K

VEHICLE
KEY NO. PART NO. DESCRIPTION QTY.

60961-749 Shear and Progressive Load Spring Service Kit,

One Side, Includes Key Nos. 12-13,15-16,

18-19, 21-23, 28

60961-750 Shear Spring Service Kit, One Side

Includes Key Nos. 12, 18-19, 21-23, 28

12 *Shear Spring 8
60961-751 Progressive Load Spring Service Kit, One Side

Includes Key Nos. 13, 15-16
13 *Progressive Load Spring 4
14 70824-001 Spacer, 63K only 4
34013-196 Progressive Load Spring Fasteners Service Kit,

One Side, Includes Key Nos. 15-16
15 *M10 x 1.5 x 40 mm 6G Flange Bolt 8
16 *M10 x 1.5 Flange Lock Nut 8
17 70886-000 Saddle 4
34013-197 Saddle Only Fastener Kit, One Side,

Includes Key Nos. 18-19
18 *M20 x 1.5 x 75 mm Flange Bolt 8
19 *M20 x 1.5 Flange Nut 8
20 77205-001 Saddle Cap 4
60961-768 Saddle Cap Fastener Service Kit, One Side,

Includes Key Nos. 21-23
21 *M16 x 2 x 6G x 180 mm Flange Bolt 8
22 *M16 Flat Washer 8
23 *M16 x 2 x 6H Nut 8
24 Shock Absorber 4
60680-015L 9½" Ride Height - 54K Rosenbauer, 58K Seagrave
60680-016L 10¼", 11½" Ride Height - 58K Seagrave

10" Ride Height - 54K and 63K KME

10½" Ride Height - 63K Rosenbauer
25 Upper Shock Bracket 2
77591-002 54K/63K Rosenbauer
77591-006 54K/63K KME
77591-007 58K Seagrave
60961-818 Upper Shock Fasteners Service Kit, One Beam,

Includes Key Nos. 26-27
26 *M16 x 2 x 140 mm Flange Bolt 4
27 *M16 x 2 Flange Nut 4
28 70867-001 P-80 Lubricant - 10 ml (Not Shown) As Req.

NOTES: * Item included in service kit/assembly only, part not sold separately.

** Transverse torque rods are mandatory for the ULTIMAAX rear suspension regardless of axle spacing.

Hendrickson Lit. No. 48422-592 – ULTIMAAX Gauge Card can be used to measure in unloaded condition (1) the length of cut / split, (2)
depth of separation and (3) the height of the progressive load spring (PLS).

17730-299 11

ULTIMAAX® for Fire and Rescue Vehicles

7

■

Torque Rod Conguration

54K / 63K – Rosenbauer

9.5" and 10½" Ride Height

54K / 63K – KME 10" Ride Height

9b

4

6

3

VEHICLE
KEY NO. PART NO. DESCRIPTION QTY.

1 Two-piece Longitudinal Torque Rod 2

65781-005 Rosenbauer, Includes Key Nos. 2a, 3 2
65781-006 KME, Includes Key Nos. 2b, 3 2
2 XTRB Straddle Bushing to Cross Member Bracket 2
a 66649-005L Rosenbauer
b 66649-002L KME
3 66649-003L XTRB Straddle Bushing to Axle Bracket, 2
4 65781-002 *Two-piece Transverse Torque Rod, 2

5 66649-002L XTRB Straddle Bushing 6
6 66649-004 XTRB Taper Bushing 2
7 22186-000 Torque Rod Frame Bracket 2
8 Torque Rod Cross Member Bracket 2
a 30828-000 Rosenbauer
b 22186-000 KME
9 Torque Rod Shim As Req.
a 49689-000 111 mm
b 67779-002 133 mm

9a

7

5

1

8

9b

1

2

9a

5

Straddle/Straddle

Straddle/Tapper, Includes Key Nos. 5-6

3

6

4

58K – Seagrave

9½", 10¼" and 11½" Ride Height

6

6

2

4

3

VEHICLE
KEY NO. PART NO. DESCRIPTION QTY.

1 ULTRA ROD® PLUS™ Longitudinal Torque Rod,

72100-495 Front, Seagrave 1
72100-635 Rear, Seagrave 1
2 72950-610 *ULTRA ROD PLUS Transverse Torque Rod, 2

3 64400-003 ULTRA ROD PLUS Straddle Bushing 6
4 64400-004 ULTRA ROD PLUS Taper Bushing 2
5 46015-000 Torque Rod Frame Bracket 4
6 67779-002 Torque Rod Shim - 133 mm As Req.

5

3

1

6

1

5

3

6

3

2

3

5

Straddle/Straddle, Includes Key No. 3

Straddle/Taper, Includes Key Nos. 3-4

4

NOTES: * Transverse torque rods are mandatory for the ULTIMAAX rear suspension regardless of axle spacing.

12 17730-299

ULTIMAAX® for Fire and Rescue Vehicles

SECTION 6

Preventive Maintenance

Following appropriate inspection procedures is important to help ensure the proper maintenance
and operation of the suspension system and component parts. Hendrickson recommends the
ULTIMAAX rear suspension be inspected at pre-delivery, the first in-service inspection and regu­lar preventive maintenance intervals. Off-highway and severe service operating conditions may
require more frequent inspections than on-highway or less severe service operations. Inspection
must include the following items and other components referenced in this section.

NOTE Torque values shown in this publication apply only if Hendrickson supplied fasteners are used. If

non-Hendrickson fasteners are used, follow the torque specification listed in the vehicle manufac­turer’s service manual.

HENDRICKSON RECOMMENDED
INSPECTION INTERVALS

Inspect Progressive Load Spring

Inspect torque rods and equalizing beam end
connections

Visually Inspect proper assembly and function. Check
for all of the following and replace components as
necessary:

• Signs of unusual movement, loose or missing
components

• Signs of abrasive or adverse contact with other
components (example: brake lines, wheel wells,
frame hangers, etc.)

• Damaged, or cracked parts

• Proper suspension function, alignment

Inspect fasteners for proper torque as recommended
in the Torque Specification Section of this publication
with special attention to the following suspension
connections:

• Equalizing beam end connection

• Saddle cap connection

• Frame hanger to frame rail connection

• Center Bushing

PRE-DELIVERY

INSPECTION

Within the first

500 Miles

(500 km)

FIRST IN-SERVICE

INSPECTION

Within the first

1,500 Miles

(2,000 km) or

100 Hours

PREVENTIVE

MAINTENANCE

Every 3 Months /

600 Hours

Every 6 Months /

1200 Hours

or

25,000 Miles /

40,000 km

Every 12 Months /

2400 Hours

Verify the alignment of axles are within the vehicle
manufacturer’s tolerances.

COMPONENT INSPECTION

Following appropriate inspection procedures is important to help ensure the proper maintenance
and operation of the ULTIMAAX heavy-duty rear suspension system and component parts. Look for
and replace worn, damaged, bent or cracked parts.

■

Cross tube — Clean the cross tube and inspect it for cracks or excessive wear 8" to 10" from
each end where it enters into the equalizing beam center bushings. Use a straight edge to
check the straightness of the cross tube. If there is a doubt as to fracture, wear or straightness,
replacement is necessary.

17730-299 13 Preventive Maintenance

ULTIMAAX® for Fire and Rescue Vehicles

and the second locating

Bottom Hole

■

Equalizing beam assembly — Check the overall condition of the equalizing beam for dents,
dings, or other damage. Check the beam end connections for tearing or extreme bulging.
Check for any metal-to-metal contact in the bushed joints. Refer to Equalizing Beam End
Connection Inspection in this section.

■

Fasteners — Look for any loose, missing or damaged fasteners on the entire suspension.
Ensure all fasteners are tightened to a torque value within the specified torque range. See rec­ommended torque specifications for Hendrickson supplied fasteners in Torque Specification
Section of this publication. For fasteners not supplied by Hendrickson, see vehicle manufac­turer. Use a calibrated torque wrench to check torque in the tightening direction. As soon as
the fastener starts to move, record the torque. Correct the torque as necessary.

NOTE Hendrickson recommends the use of Grade 8 bolts, hardened washers, and Grade C locknuts.

Hardened washers are not necessary when flange head fasteners are used.

NOTE Torque values shown in this publication apply only if Hendrickson supplied fasteners are used. If

non-Hendrickson fasteners are used, follow the torque specification listed in the vehicle manufac­turer’s service manual.

■

Saddle cap fasteners — Inspect the locknuts for proper torque to prevent wear of the beam
center bushing into the saddle. See Torque Specification Section of this publication for recom­mended torque requirements.

■

Shock absorbers — Look for any signs of dents or leakage. Misting is not considered a leak.
See Shock Absorber Inspection in this section.

■

Transverse torque rods / Longitudinal torque rods — The torque rods must be connected
and in good working condition when operating the vehicle.

■

Wear and damage — Inspect all parts of the suspension for wear and damage. Look for bent
or cracked parts.

See vehicle manufacturer’s applicable publications for other preventive maintenance
requirements.

CENTER BUSHINGS

VISUAL INSPECTION

An inspection of the center bushing is necessary when a vehicle is in the shop for major repair
work and at regular preventive maintenance intervals.

NOTE ULTIMAAX center bushing is designed with voids at front and rear, see Figure 6-1. These voids are

not an indication of wear.

FIGURE 6-1

1. Visually inspect the center bush­ing for signs of movement or
excessive wear such as frayed,
bulging or distorted rubber in the
center bushing.

2. Replacement is necessary if:

■

Any metal to metal contact is
visible.

■

Any signs that the bushing
inner metal is not centered in
the bushing.

■

Any equalizing beam to sad­dle contact.

Void

Center

Hole

C

L

Void

Horizontal Centerline
Verify the voids are

perpendicular to the
horizontal centerline

hole is on the bottom

Second Locating

Preventive Maintenance 14 17730-299

ULTIMAAX® for Fire and Rescue Vehicles

A
end hub appearing
centerline of the end bushing in the axle bracket

the centerline of the end bushing in the axle bracket

EQUALIZING BEAM END CONNECTION

An inspection of the beam end connections are necessary when a vehicle is in the shop for
major repair work and at regular preventive maintenance intervals. Periodic visual inspection by

the driver and service personnel is also recommended.

FIGURE 6-2

■

Bar Pin Style, see Figure 6-2

NOTE The equalizing beam end connection

requires that the fasteners are tightened
to torque specifications, see Figure 6-2,
to maintain the clamp load of the axle
bracket legs to the bar pin. All bushing
motion is accommodated by rubber
deflection.

VISUAL INSPECTION

1. Chock the wheels.

2. Visually inspect suspension com­ponents for signs of movement or
excessive wear.

■

Inspect alignment shims in
equalizing beam end for looseness. Lightly tap on the alignment shims to see if they
can be moved. If movement is detected, tighten fasteners to the proper torque value, see
Figure 6-2.

■

Inspect the equalizing beam end connection for signs of excessive wear or looseness.

SERVICE HINT An equalizing beam end connection that is visibly cleaner than the other connections may indi-

cate a loose connection.

■

Look for worn, frayed or distorted rubber in the bar pin beam end bushing, see Figure 6-3.

■

Look for the equalizing beam to be lower in the beam hanger, see Figure 6-3.

■

If the bar pin beam end bushing is visually offset a floor jack test should be performed,
refer to Jack Test in this section.

FIGURE 6-3

GOOD BUSHING

bushing will result in the equalizing beamGOOD

to be with thecentered

C

WORN BUSHING

Axle BracketAxle Bracket

L

A bushing will result in the equalizing beamWORN
end hub appearing to be /" (15 mm)

C

L

5

8

offset/below

17730-299 15 Preventive Maintenance

ULTIMAAX® for Fire and Rescue Vehicles

Gap in rubber
of bar pin end

ed Nut

1/" Slotted Nut

63K ShownULTIMAAX

FIGURE 6-4

JACK TEST

1. Place a jack under each beam end as shown. Raise the
jack to check for movement in the connection or rubber
components, see Figure 6-4.

NOTE The gap at each side of the visible rubber on the lower

part of the end bushing is normal, see Figure 6-4, and is
not an indication to replace the bushing. Because all rubber
end bushings are in compression, with the load bearing on
the top side, the lower side of the rubber is slightly relieved,
allowing the rubber to move inward, and a gap appears.

PHYSICAL INSPECTION

IF BAR PIN MOVEMENT OR LOOSENESS IS NOTED IN ANY OF

THE EQUALIZING BEAM END HUBS, DO NOT OPERATE THE VEHICLE. REPLACE THE RUBBER END
BUSHINGS AND ALL CONNECTING PARTS IF NECESSARY. THE ABOVE CONDITION CAN RESULT
IN COSTLY REPAIR, DOWNTIME, POSSIBLE SEPARATION OF COMPONENTS, ADVERSE VEHICLE
HANDLING, PROPERTY DAMAGE, OR PERSONAL INJURY.

Floor

Jack

Axle Bracket

bushing is
normal

SERVICE HINT An equalizing beam end connection that is visibly cleaner than the other connections may indi-

cate a loose connection.

2. If bar pin end bushing movement or looseness is detected in the equalizing beam end hub,
replace the end bushings and all connecting parts. Refer to the Component Replacement
Section of this publication.

3. Check and record torque values, as received, for each 1" bar pin fastener, see Figure 6-2.
Ensure all fasteners are tightened to:

■

At the locknut to 525 ± 75 foot pounds torque, or

■

At the bolt head to 575 ± 75 foot pounds

4. Recheck equalizing beam end connections for signs of looseness.

■

Inspect alignment shims in equalizing beam end for looseness. Lightly tap on the align­ment shims to see if they can be moved. If movement is detected, tighten fasteners to the
proper torque value, see Figure 6-2.

■

Inspect equalizing beam end connection for signs of excessive wear or looseness.

5. If bar pin looseness is still detected in any of the equalizing beam end hub, DO NOT operate
the vehicle. One or more components will require replacement, see Component Replacement
Section of this publication.

■

Adapter Style, see Figure 6-5

FIGURE 6-5

VISUAL INSPECTION

1. Chock the wheels.

Equalizing
Beam

Cotter Pin

2. Visually inspect suspension
components for signs of
movement or excessive wear.

■

Inspect the equalizing
beam end connection
for signs of excessive
wear or looseness.

■

Look for worn, frayed or
distorted rubber in the beam, see Figure 6-6.

7

8

Beam End Shaft

Beam End Adapter

Adapter Style
End Bushing

7

8

1/" Slott

Beam End Adapter

Preventive Maintenance 16 17730-299

■

in the axle bracket

in the axle bracket

Flat Side

Chisel Reliefs

er

Look for the equalizing beam to be lower in the axle bracket, see Figure 6-6.

■

If the adapter style end bushing is visually offset, a floor jack test should be performed,
refer to Jack Test in this section.

FIGURE 6-6

GOOD BUSHING

ULTIMAAX® for Fire and Rescue Vehicles

WORN BUSHING

Axle Bracket

C

L

A bushing will result in the equalizingGOOD
beam end hub appearing to be centered
with the centerline of the end bushing

FIGURE 6-7

A bushing will result in the equalizingWORN
beam end hub appearing to be /" (15 mm)
offset/below the centerline of the end bushing

3. The beam end adapter style connections have
the flange of the adapter cut off for assembly
clearance with the axle housing bowl.

■

The flat must be positioned vertically as
shown in Figure 6-7. If the flat of the adapter
position is incorrect, removal of the fasten­ers will be necessary to correct position,

Equalizing
Beam

refer to the Adapter Style End bushings in
the Component Replacement Section.

JACK TEST

FIGURE 6-8

1. Place a jack under each beam end as shown.
Raise the jack to check for movement in
the connection or rubber components, see
Figure6-8.

Axle Bracket

C

L

Axle Bracket

5

8

Adapter

Adapter

Vertical

Axle Bracket
Supplied by
Vehicle
Manufactur

NOTE The gap at each side of the visible rubber on the

lower part of the bar pin end bushing is normal,
see Figure6-8, and is not an indication to replace
the bushing. Because all rubber end bushings are
in compression, with the load bearing on the top
side, the lower side of the rubber is slightly relieved,
allowing the rubber to move inward, and a gap

Gap in rubber of
End Bushing
is normal

appears.

PHYSICAL INSPECTION

IF BUSHING MOVEMENT OR LOOSENESS IS NOTED IN THE EQUALIZING BEAM END HUB, DO NOT

17730-299 17 Preventive Maintenance

OPERATE THE VEHICLE. REPLACE THE RUBBER END BUSHINGS AND ALL CONNECTING PARTS.
THE ABOVE CONDITION CAN RESULT IN COSTLY REPAIR, DOWNTIME, POSSIBLE SEPARATION OF
COMPONENTS, ADVERSE VEHICLE HANDLING, PROPERTY DAMAGE, OR PERSONAL INJURY.

ULTIMAAX® for Fire and Rescue Vehicles

ed Nut

Beam End Adapter

700 ± 50 ft.

ed.

Shim Type Bar Pin End Bushing

SERVICE HINT An equalizing beam end connection that is visibly cleaner than the other connections may indi-

cate a loose connection.

2. If bushing movement or looseness is detected in the equalizing beam end hub, DO NOT oper-

ate vehicle. Replace the equalizing beam end bushings and all connecting parts. Refer to the
Component Replacement Section of this publication.

3. Check and record torque values, see Figure 6-9. Correct torque values as required making
sure all fasteners are tightened to
torque.

FIGURE 6-9

63K ShownULTIMAAX

7

8

1/" Slotted Nut

Tightening Torque

125 ft. lbs. (170 Nm)

+ 90° rotation or

lbs.(949 ± 68 Nm)

125 foot pounds + 90° rotation or 700 ± 50 foot pounds

Equalizing Beam

Beam End Shaft

Adapter Style
End Bushing

Cotter Pin

7

8

1/" Slott

Beam End Adapter

FIGURE 6-11

BAR PIN END BUSHINGS

FIGURE 6-10

VISUAL INSPECTION

An indication that the bar pin end bushing requires
replacement is when one or more of the following
conditions apply:

■

If the contact area, see Figure 6-10 (the flat face
area where bar pin contacts the axle bracket)
reveal signs of excessive wear. Replace if bar pin
thickness measures less than 17⁄8" (47.59mm).

■

If bar pin bolt holes bores reveal signs of elonga­tion or wear, see Figure 6-10.

BAR PIN SHIMS

An indication that the bar pin shims require
replacement is when one or more of the following
conditions apply:

■

Visual inspection of contact area on the shim reveals signs of excessive wear.

■

The thickness of any single leg on the shim, is less than the measurement shown in
Figure6-11, replacement of bar pin shim is required.

Original

Thickness

of Shim Leg

Contact Area

Bolt Hole
Bore

Confinement
Washer

Bar Pin

1.874"

(47.59 mm)

If bar pin measurement is less than

1.874" (47.59 mm),replacement is requir

Minimum
Thickness

Required

Part Number

1

⁄8" (3.2 mm) 0.123" (3.1 mm) 50131-000

3

⁄16" (4.8 mm) 0.186" (4.7 mm) 50130-000

¼" (6.4 mm) 0.248" (6.3 mm) 50131-000

3

⁄8" (9.5 mm) 0.371" (9.4 mm) 57026-000

Preventive Maintenance 18 17730-299