• 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

KEY NO. PART NO.
DESCRIPTION

1

VEHICLE
QTY.

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
*Shear Spring
8
60961-751
Progressive Load Spring Service Kit, One Side
Includes Key Nos. 13, 15-16
*Progressive Load Spring
4
70824-001
Spacer, 63K only
4
34013-196
Progressive Load Spring Fasteners Service Kit,
One Side, Includes Key Nos. 15-16
*M10 x 1.5 x 40 mm 6G Flange Bolt
8
*M10 x 1.5 Flange Lock Nut
8
70886-000
Saddle
4
34013-197
Saddle Only Fastener Kit, One Side,
Includes Key Nos. 18-19
*M20 x 1.5 x 75 mm Flange Bolt
8
*M20 x 1.5 Flange Nut
8
77205-001
Saddle Cap
4
60961-768
Saddle Cap Fastener Service Kit, One Side,
Includes Key Nos. 21-23
*M16 x 2 x 6G x 180 mm Flange Bolt
8
*M16 Flat Washer
8
*M16 x 2 x 6H Nut
8
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
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
*M16 x 2 x 140 mm Flange Bolt
4
*M16 x 2 Flange Nut
4
70867-001
P-80 Lubricant - 10 ml (Not Shown)
As Req.
60961-749

12
13
14
15
16
17
18
19
20
21
22
23
24

25

26
27
28

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
■■ Torque

Rod Configuration

54K / 63K – Rosenbauer
9.5" and 10½" Ride Height
54K / 63K – KME 10" Ride Height

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

9a

6

9b
7
4

2
5

6

5

6

1

3
8

3

4

9b
1
3
2

1
6

3
1

4

5 3

6

6

9a

3
2
4
7

KEY NO. PART NO.
DESCRIPTION
1

2
3
4
5
6
7
8
9

a
b

a
b
a
b

5

3

5

VEHICLE
QTY.

Two-piece Longitudinal Torque Rod
2
Straddle/Straddle
65781-005 Rosenbauer, Includes Key Nos. 2a, 3
2
65781-006 KME, Includes Key Nos. 2b, 3
2
XTRB Straddle Bushing to Cross Member Bracket 2
66649-005L Rosenbauer
66649-002L KME
66649-003L
XTRB Straddle Bushing to Axle Bracket,
2
65781-002
*Two-piece Transverse Torque Rod,
2
Straddle/Tapper, Includes Key Nos. 5-6
66649-002L
XTRB Straddle Bushing
6
66649-004
XTRB Taper Bushing
2
22186-000
Torque Rod Frame Bracket
2
Torque Rod Cross Member Bracket
2
30828-000 Rosenbauer
22186-000 KME
Torque Rod Shim
As Req.
49689-000 111 mm
67779-002 133 mm

KEY NO. PART NO.
DESCRIPTION
1

2
3
4
5
6

VEHICLE
QTY.

ULTRA ROD® PLUS™ Longitudinal Torque Rod,
Straddle/Straddle, Includes Key No. 3
72100-495 Front, Seagrave
1
72100-635 Rear, Seagrave
1
72950-610
*ULTRA ROD PLUS Transverse Torque Rod,
2
Straddle/Taper, Includes Key Nos. 3-4
64400-003
ULTRA ROD PLUS Straddle Bushing
6
64400-004
ULTRA ROD PLUS Taper Bushing
2
46015-000
Torque Rod Frame Bracket
4
67779-002
Torque Rod Shim - 133 mm
As Req.



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

PRE-DELIVERY
INSPECTION

FIRST IN-SERVICE
INSPECTION

PREVENTIVE
MAINTENANCE
Every 3 Months /
600 Hours

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:
• S igns of unusual movement, loose or missing
components
• S igns of abrasive or adverse contact with other
components (example: brake lines, wheel wells,
frame hangers, etc.)
• Damaged, or cracked parts
• Proper suspension function, alignment

Within the first
500 Miles
(500 km)

Inspect fasteners for proper torque as recommended
in the Torque Specification Section of this publication
with special attention to the following suspension
connections:
• E qualizing beam end connection
• S addle cap connection
• F rame hanger to frame rail connection
• Center Bushing

Within the first
1,500 Miles
(2,000 km) or
100 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
■■ 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:
■■

■■

■■

Preventive Maintenance

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.

14

Void

Horizontal
Centerline

Void

CL

Verify the voids are
perpendicular to the
horizontal centerline
and the second locating hole
is on the bottom.

Center Hole
Second Locating
Bottom Hole

17730-299

ULTIMAAX® for Fire and Rescue Vehicles
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
■■

NOTE

Bar Pin Style, see Figure 6-2

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.
■■

■■

SERVICE HINT

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.

An equalizing beam end connection that is visibly cleaner than the other connections may indicate 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

WORN BUSHING

Axle Bracket

Axle Bracket

C
L

C
L

A GOOD bushing will result in the equalizing beam
end hub appearing to be centered with the
centerline of the end bushing in the axle bracket

17730-299

15

A WORN bushing will result in the equalizing beam
end hub appearing to be 5/8" (15 mm) offset/below
the centerline of the end bushing in the axle bracket

Preventive Maintenance

ULTIMAAX® for Fire and Rescue Vehicles
FIGURE 6-4

JACK TEST

Axle Bracket

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.

Floor
Jack

Gap in rubber
of bar pin end
bushing is
normal

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.

SERVICE HINT

An equalizing beam end connection that is visibly cleaner than the other connections may indicate 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