1. Install the transverse torque rod.
2. Install the mounting fasteners and any shims that were removed.
NOTE

Hendrickson recommends the using Grade 8 bolts and Grade C locknuts for all torque rod
attachments.
3. Prior to tightening, ensure that the vehicle is at the proper ride height. Tighten all fasteners to
the required torque specification. Refer to original equipment manufacturer for specifications.
4. Check the lateral alignment. If not within vehicle manufacturer’s specified range, a lateral
alignment is necessary. See Lateral Alignment in the Alignment & Adjustments Section of this
publication.
5. Remove the wheel chocks.

TORQUE ROD BUSHINGS
■■ ULTRA ROD PLUS, see Figure 8-47
FIGURE 8-47
Taper Pin Bushing

You will need:
■■ A vertical press with a capacity of at least

10 tons

■■ Shop made receiving tool and installation/

removal tool, refer to the Special Tools Selection
of this publication for more information

■■ Funnel Tool No. 66086-000, refer to the Special

Tools Selection of this publication for more
information

Component Replacement

52

Straddle Pin Bushing

17730-299

ULTIMAAX® for Fire and Rescue Vehicles
DISASSEMBLY
1. Remove torque rods as detailed in Torque Rod Disassembly instructions in this section.
DO NOT USE HEAT OR USE A CUTTING TORCH TO REMOVE THE BUSHINGS FROM THE TORQUE ROD. THE
USE OF HEAT WILL ADVERSELY AFFECT THE STRENGTH OF THE TORQUE ROD, HEAT CAN CHANGE THE
MATERIAL PROPERTIES. A COMPONENT DAMAGED IN THIS MANNER CAN RESULT IN ADVERSE VEHICLE
HANDLING AND POSSIBLE PERSONAL INJURY OR PROPERTY DAMAGE.

2. Support the torque rod end tube centered on the receiving tool. Be sure the torque rod is
squarely supported on the press bed for safe­ty.
3. Push directly on the straddle mount bar pin, until the top of the pin is level with the top of
torque rod end tube. Place the push out tool directly on top of the bar pin and press until the
bushing clears the torque rod end tube.
4. Remove the fasteners from the tapered bar pin bushing, and support the torque rod end on
the receiving tool with the tapered stud pointing up and the end tube centered on the tool. Be
sure the torque rod is squarely supported on the press bed for safety.
5. Push directly on the tapered stud until the bushing clears the torque rod end tube.

ASSEMBLY
1. Clean and inspect the inner diameter of the torque rod end tubes.
NOTE

DO NOT use paraffinic oil, or soap base lubricant. Such lubricants can cause adverse reactions
with the bushing, such as deterioration of the rubber, causing premature failure. Use ONLY a light
Naphthenic base oil, such as 60 SUS at 100°F.
FIGURE 8-48

2. Lubricate the inner diameter of the torque rod
end tubes and the new rubber bushings with
a light Naphthenic base oil, such as 60 SUS at
100°F, see Figure 8-48.
3. Support the torque rod end tube centered on the
receiving tool. Ensure the torque rod is squarely
supported on the press bed for safety.
4. Place the assembly funnel tool centered on the
torque rod end hub, see Figure 8-50.
5. Place the torque rod bushing centered in the assembly funnel.
6. The straddle mount bar pin bushings must have the mounting flats positioned at zero degrees to
the shank of the torque rod, see Figure 8-49.
FIGURE 8-49

7. Press the bar pin through the assembly funnel into torque rod end hub until the rubber clears
the assembly funnel, see Figure 8-51.
8. Push directly on the straddle mount bar pin, or the tapered stud. The bushing must be centered within the end hubs of the torque rod.
■■

17730-299

When pushing in the new rubber bushings, overshoot the desired final position by approximately 3/16" (4.76 mm), see Figure 8-52.

53

Component Replacement

ULTIMAAX® for Fire and Rescue Vehicles
■■

Push the rubber bushing again from the opposite side to center the rubber bushing within
the end hub, see Figure 8-53.

FIGURE 8-50

FIGURE 8-51

FIGURE 8-52

FIGURE 8-53

IF THE TORQUE ROD ASSEMBLY IS NOT ALLOWED THE ALLOTTED TIME FOR THE LUBRICANT TO DISSIPATE,
THE BUSHING MAY SLIDE FROM THE TORQUE ROD END HUB CAUSING THE BUSHING TO BE REMOVED
AND A NEW BUSHING RE-INSTALLED.

9. Wipe off the excess lubricant. Allow the lubricant four hours to dissipate prior to operating the
vehicle.
10. Install the torque rod as detailed in the Torque Rod Assembly instructions in this section.
FIGURE 8-54
■■

XTRB, see Figure 8-54

You Will Need:
■■ A vertical press with a capacity of at least 10 tons
■■ Shop made receiving tool and installation / removal tool,

refer to the Special Tools Section of this publication for
more information.

BUSHING REMOVAL
1. Remove torque rods as detailed in Torque Rod
Disassembly instructions in this section.
DO NOT USE HEAT OR USE A CUTTING TORCH TO REMOVE THE BUSHINGS FROM THE TORQUE ROD.
THE USE OF HEAT WILL ADVERSELY AFFECT THE STRENGTH OF THE TORQUE ROD, HEAT CAN CHANGE
THE MATERIAL PROPERTIES. A COMPONENT DAMAGED IN THIS MANNER CAN RESULT IN THE ADVERSE
VEHICLE HANDLING AND POSSIBLE PERSONAL INJURY OR PROPERTY DAMAGE.
Component Replacement

54

17730-299

ULTIMAAX® for Fire and Rescue Vehicles
2. Straddle Mount Bar Pin Bushing —When servicing a straddle mount bar pin bushing assembly, mark the clocking position of the straddle mount bar pin flats with a paint stick on the
torque rod end hub prior to disassembly, see Figure 8-55. This marking will serve as a guide
when installing the new bushing so the original clocking position can be retained.
3. Taper Pin Bushing — Remove the fastener and the concave washer from the taper pin
bushing.
4. Support the torque rod end hub and centered on the receiving tool (for a tapered bushing,
have the tapered stud pointing down). Ensure the torque rod is squarely supported on the
press bed for safe­ty.
5. Install the removal tool, see Figure 8-56.
6. Press directly on the removal tool until the bushing clears the torque rod end hub, see
Figure 8-57.
FIGURE 8-55

FIGURE 8-56

FIGURE 8-57

Mark the clocking position of the
bar pin flats with a paint stick
on the torque rod end hub
Torque Rod
Bushing
Installation /
Removal Tool

Torque Rod
Bushing
Receiving Tool

BUSHING INSTALLATION
1. Clean and inspect the inner diameter of the torque rod end hubs, see Figure 8-58.
SERVICE HINT

DO NOT use a paraffinic oil, or soap base lubricant. Such lubricants can cause adverse reactions
with the bushing, causing premature failure.
2. Lubricate the inner diameter of the torque rod end hubs and the outer metal of new bushings
with NLGI #2 EP grease, see Figure 8-59.
FIGURE 8-58

FIGURE 8-59

Inspect and clean the inner
diameter of torque rod
end hubs

17730-299

Apply NLGI #2-EP (Extreme Pressure)
lubricant to the inner diameter of torque
rod end hub and bushings

55

Component Replacement

ULTIMAAX® for Fire and Rescue Vehicles
FIGURE 8-60

3. Support the torque rod end hub centered on the
receiving tool. Ensure the torque rod is squarely supported on the press bed for safety.
4. Straddle Mount — Place the straddle mount bushing in the end hub and re-align the bar pin bushings
to the mark made prior to removal as shown in
Figure 8-55.
5. Taper Pin — Place the taper pin bushing in the end
hub with the taper pointing down. Tighten 5⁄8" bolt
head to 65 ± 5 torque, see Figure 8-60.
6. Using the shop made tool, place the installation tool on the bushing and press in, see
Figure 8-57.
7. Ensure the bushing is centered within the hub of the torque rod.
8. Wipe off the excess lubricant.
9. Replace torque rod assembly as detailed in the Transverse or Longitudinal Torque Rod
Component Replacement Section in this publication.

Component Replacement

56

17730-299

ULTIMAAX® for Fire and Rescue Vehicles
SECTION 9

Troubleshooting Guide
ULTIMAAX for Fire and Rescue Vehicles
TROUBLESHOOTING GUIDE
CONDITION
Suspension has harsh or
bumpy ride

Vehicle leans

Irregular tire wear

POSSIBLE CAUSE

CORRECTION

Damaged shock absorber

Replace shock absorbers

Damaged progressive load spring

Replace progressive load springs, must be replaced in pairs

Damaged shear spring

Replace shear spring

Vehicle overloaded

Redistribute or reduce load to correct weight

Damaged progressive load spring

Replace progressive load springs, must be replaced in pairs

Damaged shear spring

Replace shear spring

Bent cross tube

Replace cross tube

Weight bias

Redistribute load to correct weight bias

Incorrect axle alignment

Axle alignment is permanently set at the time of vehicle
manufacture. Contact vehicle manufacturer.

Bent cross tube

Replace cross tube

Damaged, bent, cracked suspension
component

Replace damaged component
Reduce and/or redistribute load to correct weight

Suspension is overloaded

Replace and/or properly tighten fasteners to the proper torque
specification

Loose or missing suspension
fasteners

Increase inspection interval of fasteners
Improper torque or over torque

Replace and/or properly tighten fasteners to the proper torque
specification
Replace frame hanger assembly

Suspension is overloaded

Reduce and/or redistribute load to correct weight
Replace frame hanger assembly

Frame hanger cracked

Saddle leg to equalizing
beam contact

17730-299

Loose or missing suspension fasteners

Increase inspection interval of fasteners
Replace fasteners and/or properly tighten fasteners to the
proper torque specification

Damaged frame hanger assembly

Replace frame hanger assembly

Damaged, bent, worn, or cracked
suspension component(s)

Replace damaged component

Cross tube bent or missing

Replace cross tube

Loose or worn saddle hex bolts

Replace saddle hex bolts, inspect mating components

Saddles not center on equalizing beam

Center saddles on the equalizing beam

Saddles not center on center bushing

Replace center bushing

57

Component Replacement

ULTIMAAX® for Fire and Rescue Vehicles
SECTION 10

Hendrickson Recommended Torque Values Provided in
Foot Pounds and in Newton Meters

Torque Specifications

Component Replacement

58

17730-299

ULTIMAAX® for Fire and Rescue Vehicles

ULTIMAAX for Fire and Rescue Vehicles
HENDRICKSON RECOMMENDED TORQUE SPECIFICATIONS
FASTENER
NO.

COMPONENT

TORQUE VALUE

*QUANTITY

SIZE

FOOT
POUNDS

NEWTON
METERS

1

Saddle Assembly to Saddle Cap

8

M16

200 ± 20

270 ± 30

2

Saddle Assembly to Progressive Load Spring

8

M10

30 ± 2

41 ± 3

3

Saddle Assembly Halves

8

M20

325
+ 90° rotation
or 560 ± 30

440
+ 90° rotation
or 760 ± 40

At Locknut

8

1"

525 ± 75

712 ± 102

At Bolt Head

8

1"

575 ± 75

780 ± 102

4a
4b

End Bushing – Bar Pin Style

5

End Bushing – Adapter Style

4

17⁄8"

125
+ 90° rotation
or 700 ± 50

170
+ 90° rotation
or 949 ± 68

6

Shock Absorber to Upper Shock Bracket

4

M16

170 ± 20

231 ± 27

7

Shock Absorber to Lower Shock Bracket

4

5/8"

80 ± 10

109 ± 14

At the Locknut

2

1¼"

200 ± 25

271 ± 34

At the Bolt Head

2

5/8"

65 ± 5

88 ± 7

8a
8b

Transverse Torque Rod to Axle

NOTE: * Quantities shown are per suspension.
** 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.

17730-299

59

Component Replacement

ULTIMAAX® for Fire and Rescue Vehicles
Hendrickson Recommended Torque Values Provided in
Foot Pounds and in Newton Meters

One and Two-piece Torque Rods

ULTIMAAX for Fire and Rescue Vehicles
HENDRICKSON RECOMMENDED TORQUE SPECIFICATIONS
FASTENER
NO.
1a
1b

COMPONENT

Transverse Torque Rod

TORQUE VALUE

*QUANTITY

SIZE

FOOT
POUNDS

NEWTON
METERS

At the Locknut

2

1¼"

200 ± 25

271 ± 34

At the Bolt Head

2

5/8"

65 ± 5

88 ± 7

NOTE: * Quantities shown are per suspension.
** 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.

www.hendrickson-intl.com

Truck Commercial Vehicle Systems
800 South Frontage Road
Woodridge, IL 60517-4904 USA

17730-299 Rev B 07-18

1.866.755.5968 (Toll-free U.S. and Canada)
1.630.910.2800 (Outside U.S. and Canada)
Fax 1.630.910.2899

Information contained in this literature was accurate at the time of publication. Product changes may have been made after the copyright date that are not reflected.
© 2016 – 2018 Hendrickson USA, L.L.C. All Rights Reserved

Printed in United States of America