9000

27

28

29

32

34

38

10000

31

32

33

36

39

43

11000

35

36

37

40

43

48

12000

39

40

41

44

48

53

AXLE LOAD (in pounds)

*RIDE AIR SPRING
EXTENSION (in inches)

13000

43

44

45

48

52

58

14000

47

48

49

53

57

63

15000

51

52

53

57

61

68

16000

55

56

57

61

66

73

17000

59

60

61

65

71

78

18000

64

65

65

70

75

83

19000

68

68

69

74

80

87

20000

71

72

73

78

84

92

21000

75

76

77

82

88

97

22000

78

80

81

86

93

101

23000

82

84

85

91

97

106

24000

86

88

89

95

102

111

25000

90

92

93

99

106

116

ESTIMATED AIR SYSTEM PRESSURE REQUIREMENTS
(in PSI)

TOUGHLIFT LK 25

*To measure ride air spring extension and axle lift, see Figure 6–1.
Air Pressure Load Information

14

OM–H754

Owner’s Manual – Steerable Auxiliary Lift Axle Systems
SECTION 7

Torque Specifications
STEERABLE AUXILIARY LIFT AXLE SYSTEM
HENDRICKSON RECOMMENDED TORQUE SPECIFICATIONS
SIZE

TORQUE VALUE
(FOOT POUNDS)

Pivot Bolt

¾"

275–300

2.

Pivot Bolt / Shift Arm

7⁄8"

425–475

3.

Frame Attachment Bolt (Recommended)

DESCRIPTION
1.

¾"

300–325

3⁄8"

25–30

½"

25–30

½"

45–50

¾"

45–50

Attachment

7⁄8"

425–475

Adjustment

5⁄8"

180–190

Attachment

7⁄8"

125–180

Adjustment

5⁄8"

45–50

Attachment

7⁄8"

425–475

Adjustment

5⁄8"

180–190

Stabilizer Shock Bolt

¾"

75–125

Suspension Cross Member Bolt

5⁄8"

160–180

16.

Brake Bolts

9⁄16"

90–110

17.

Bolt-on Brake Attachments

5⁄8"

160–180

7⁄16"

40–50

4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.

18.
19.
20.
21.

Air Spring Bolt (Lower)
Air Spring Nut (Upper)
Compliant Tie Rod (CTR)
Round Tube Tie Rod
Heavy-duty (HD) Tie Rod

Shift Chamber Attachment
Shift Chamber Yoke Attachment

5⁄8"

130–150

7⁄16"

70–90

5⁄8"

35–45
425–475
450–495

22.

Radius Rod Bolt

7⁄8"

23.

U-bolts

7⁄8"

NOTE: T orque values shown apply only if Hendrickson supplied fasteners are used. If non–Hendrickson fasteners are used, follow the torque
specification listed in vehicle manufacturer’s service manual.

OM–H754

15

Torque Specifications

Owner’s Manual – Steerable Auxiliary Lift Axle Systems
SECTION 8

Troubleshooting Guide
STEERABLE AUXILIARY LIFT AXLE SYSTEM
TROUBLESHOOTING GUIDE
PROBLEM
Not getting the
desired load on
the axle

POSSIBLE CAUSE

CORRECTION

Air control system not properly installed

a. Adjust the air pressure at regulator valve
b. Verify sufficient pressure to the air control system
Check plumbing of air system, refer to Hendrickson Publication No. OM‑H817

Mounted too high

Larger tire

Incorrect ride height specification

Change axle seat height
a. Check system pressure
b. Check air system plumbing, refer to Hendrickson Publication No. OM‑H817
c. Check air spring pressure

Improper air pressure to the ride bags

Lift air springs not getting proper air pressure
Unit not getting
the correct lift

Unit has vertical
hop

Interference with chassis, drive line or other
components
Unit not installed properly

Check installation with factory installation drawing

Not running sufficient load

Increase air system pressure

Unbalanced tires

Balance tires

Improper caster setting

Re–adjust caster if possible

Toe setting is incorrect

Axle out of alignment

Re–adjust toe setting, refer to Hendrickson Publication No. TP–H785
Re–torque to factory torque values, see Torque Specification
Section in this publication
Re–torque to factory torque values, see Torque Specification Section in this
publication
Re-align axle

Tires different size on each side

Use same size tires

Tires unbalanced

Balance tires

Air pressure in tires different from side to side

Equalize air pressure

Axle bolt connection loose
Axle shimmy

Inspect for interference

Pivot bolt connection loose

Stabilizers worn

Verify stabilizer resistance and replace as necessary

Axle does not
track forward

Toe setting

Set toe, refer to Hendrickson Publication No. TP–H845

Axle does not
track in reverse
(Reverse Caster
Only)

Inadequate air pressure to forward shift
Increase air pressure minimum (100 psi)
chambers
One or both forward shift chambers is damaged Replace chamber(s)
Hanger bracket mounted incorrectly on the frame
Remount frame rail bracket
rail
a. Contact Hendrickson Customer Service to spec out a unit with reverse
Installed unit is not designed to accommodate
caster if required or
the reverse castor option
b. Lift axle is in reverse, if reverse caster is not necessary

Axle in reverse
Incorrect air line plumbing
caster when lifted

Correct air plumbing, refer to Hendrickson Publication No. OM–H817

Actual product performance may vary depending upon vehicle configuration, operation, service and other factors.
All applications must comply with applicable Hendrickson specifications and must be approved by the respective vehicle manufacturer with the vehicle in its original, as-built configuration.
Contact Hendrickson for additional details regarding specifications, applications, capacities, and operation, service and maintenance instructions.

Call Hendrickson at 800.660.2829 or 800.668.5360 in Canada for additional information.

www.hendrickson-intl.com
H754 Rev F 03-19

SPECIALTY PRODUCTS AUXILIARY AXLE SYSTEMS
277 North High Street
Hebron, OH 43025 USA
800.660.2829
740.929.5600 • Fax 740.929.5601

Hendrickson Canada
250 Chrysler Drive, Unit #3
Brampton, ON Canada L6S 6B6
800.668.5360
905.789.1030 • Fax 905.789.1033

© 2019 Hendrickson USA, L.L.C. All Rights Reserved. All trademarks shown are owned by Hendrickson USA, L.L.C., or one of its affiliates, in one or more countries.
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.

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