--------------------------~-~--

~TECHNICAL

PROCEDURE

Freightliner Vehicles equipped
with AIRTEK® Suspension System
SUBJECT: Pre-delivery Inspection and Preventive
Maintenance, Rear Shackle Bracket
and Front/Rear Spring Eye Connections
LIT NO: 17730-236
DATE: October 2013
REVISION: A

INTRODUCTION
This publication primarily focuses on proper pre-delivery inspection and preventive maintenance of rear
shackle bracket and front and rear spring eye components of AIRTEK® suspension systems as installed
on applicable Freightliner vehicles built after May 2010. This information is intended as a supplement to
Hendrickson Technical Procedure Literature No. 17730-243.
Following appropriate inspection and preventive maintenance procedures is important to help ensure the
proper service and operation of the AIRTEK system. Hendrickson recommends the AIRTEK system is inspected
at pre-delivery, the first l ,000 miles of service, and at the regular preventive maintenance intervals.
Carefully inspect the AIRTEK rear shackle brackets and front/rear spring eye connections using the following
instructions, refer to Hendrickson Literature No. 17730-243 for complete AIRTEK suspension inspection procedures, important safety notices, and preventive maintenance details, available at www.hendrickson-intl.com.

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.

SAFETY REMINDER
All applicable warnings and cautions 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 manufacturer's warranty.
Failure to follow the applicable safety precautions can result in personal injury and/or property damage.
Carefully read and understand all safety related information within the applicable Hendrickson publications, on all decals and those materials provided by the vehicle manufacturer before operating the
vehicle, or conducting any maintenance, service or repair.

HENDRICKSON RECOMMENDED PREVENTIVE MAINTENANCE INTERVALS
PRE-DELIVERY INSPECTION - First l 00 Miles/150 Kilometers or prior to VEHICLE IN-SERVICE
a. Visually inspect the suspension for proper assembly.
b. Visually inspect the overall condition of the rear shackle brackets, shackle plates, and front/rear spring
eye connections, front axle, leaf springs, and top pads for any damage.
c. Check all fasteners for proper torque with special attention to the following suspension connections: rear shackle bracket connections. front/rear spring eye connections, and clamp group
mounting hardware. Use a calibrated torque wrench to check torque in a tightening direction.
d. Verify the ride height is within specification by using Ride Height Gauge 457 45-159, for more details
refer to the Alignment and Adjustment Section, Hendrickson Literature No. 17730-243.

~HENDRICKSON
.

~ ~O?H~.uMs Oh Us®

'H
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AIRTEK® Suspension System for FreightlinerVehicles
INSPECTION - First 1,000 miles /1,600 kilometers of pre-delivery or suspension service
a. Visually inspect suspension components. Check for:
•
•
•
•

Proper suspension function
Signs of unusual movement, or loose or missing components
Signs of abrasive or adverse contact between components
Damaged, bent or cracked parts

b. Check all fasteners for proper torque with special attention to the following suspension connections: rear shackle bracket connections, front/rear spring eye connections, and clamp group
mounting hardware. Use a calibrated torque wrench to check torque in a tightening direction.

PREVENTIVE MAINTENANCE - On-highway, every 50,000 miles (80,000 km) or
six (6) months, whichever comes first
a. Visually inspect suspension components. Check for:
• Proper suspension function
• Signs of unusual movement, or loose or missing components
• Signs of abrasive or adverse contact between components
• Damaged, bent or cracked parts
b. Check all fasteners for proper torque value with special attention to rear shackle bracket and front/
rear spring eye connections. Use a calibrated torque wrench to check torque in a tightening direction.

COMPONENT INSPECTION
• Fasteners - Look for any loose or damaged fasteners on the entire suspension. Make sure all fasteners are tightened to the specified torque. Refer to Hendrickson Literature No. 17730-243 for torque
specifications. Use a calibrated torque wrench to check torque in a tightening direction.As soon as the
fastener starts to move, record the torque. Correct the torque if necessary. Replace any worn or damaged fasteners.
• Rear shackle bracket and front/rear spring eye connections - Check for loose or damaged mounting fasteners. Verify Hendrickson supplied fasteners are tightened to specifications per Hendrickson
Torque Specifications. If fasteners are not supplied by Hendrickson, see the vehicle manufacturer's
specifications. See the Shackle Bracket and Front/Rear Spring Eye Connection Inspection Section in
this publication.Also check hangers/shackle bracket for any signs of excessive wear or cracks. Replace
if necessary, refer to Component Replacement Section of Hendrickson Literature No. 17730-243 for
replacement procedure.
• Steel leaf springs - Look for cracks. Replace if cracked or broken. Check the front and rear spring eye
bushings for any wear or deterioration. Replace leaf spring assembly if any of the previous conditions
are observed, refer to Component Replacement Section of Hendrickson Literature No. 17730-243 for
replacement procedure.
• Wear and damage - Inspect all parts of suspension for wear and damage. Look for bent or cracked
parts. Replace all worn or damaged parts.
See the vehicle manufacturer's applicable publications for other preventive maintenance requirements.

SHACKLE BRACKET & FRONT/REAR SPRING EVE CONNECTION INSPECTION
VISUAL INSPECTION
In normal use these components will function satisfactorily, even though the components may show
some wear.
Some signs of a loose or worn connection that can result in component damage may include the following, also see Figure 1. If any of the below are present, then a Physical Inspection is necessary.
• The vehicle exhibits a popping or clunking sound • The rear spring eye is in contact with the
when turning.
shackle plates.
• The front spring eye is in contact with the frame • The rear shackle bracket and bushing assemhanger
bly is in contact with the shackle plate.
• Excessive lateral movement of the leaf spring.
2

17730-236

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AIRTEK® Suspension System for Freightliner Vehicles
PHYSICAL INSPECTION
1. Chock the wheels.
2.

Remove fasteners from the spring eye connection(s).

3.

Inspect the hanger, or shackle plate, shackle bracket and mating components, if any of the components exhibit any signs of damage or excessive wear, the component and/or mating components
require replacement,also see Figure 1. Refer to Hendrickson Literature No. 17730-243 for component replacement.
When component replacement is complete, continue with Torque Inspection.

4.

FIGURE l
INSPECT FOR INDICATIONS OF A LOOSE JOINT

Shackle Plate
Loose Joint
Worn Inside Leg

Shackle Plate

Front/Rear Spring Eye
Loose Joint, Elongated Hole
Worn Bushing Inner Metal
due to low clamp load

TORQUE INSPECTION

A

WARNING

LOOSE OR OVER TORQUED FASTENERS CAN CAUSE COMPONENT DAMAGE, LOSS OF VEHICLE CONTROL,
PROPERTY DAMAGE, OR SEVERE PERSONAL INJURY. MAINTAIN CORRECT TORQUE VALUES AT ALL TIMES.
CHECK TORQUE VALUES ON A REGULAR BASIS AS SPECIFIED.

1. Chock the wheels.
2. Verify the ride height is within specification by using Ride Height Gauge 457 45-159, for more details
refer to the Alignment and Adjustment Section, Hendrickson Literature No. 17730-243.

NOTE

17730-236

Any adjustment of the ride height will still require a loosening and re-torque of the two (2) spring eye
fasteners and the four (4) rear shackle bracket fasteners at the corrected ride height, regardless of
prevailing torque.
3.

If ride height is out of specification, adjust the ride height to the correct specification; refer to
Ride Height Adjustment in the Alignment and Adjustment Section of Hendrickson Literature No.
17730-243. Any adjustment of the ride height will still require a loosening and re-torque of the two
(2) spring eye fasteners and the four (4) rear shackle bracket fasteners at the corrected ride height,
regardless of prevailing torque, see Steps 7-9.

4.

Check prevailing torque load at the two (2) front spring eye fasteners and four (4) rear shackle
bracket fastener locations.

5.

Set the torque wrench to ~ 200 foot pounds and check the torque at all six locations as shown in
Figure 2. Use a calibrated torque wrench to check torque in a tightening direction.
• If no locknut movement is observed, increase torque wrench setting in 5 foot pound increments until the movement is observed, record torque value, proceed to Step 6.
• If locknut movement is observed, torque value was below 200 foot pounds, proceed to Step 6.

3

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AIRTEK® Suspension System for Freightliner Vehicles
FIGURE 2

6.

See the appropriate action below:

Freightliner vehicles built AFTER May 2010

• If the torque value is at or above
250 foot pounds and at the correct
received ride height, then no further
action is necessary.
• If the torque value is below 250 and
above 200 foot pounds, a re-torque is
necessary, see Steps 7-9.

i.ring

Eye Fastener
Tighten to 250 ft. lbs.

• If the torque value is below 200 foot .
pounds, disassemble the shackle/
spring eye joint and inspect all mating components for wear or damage, NOTE: *Spring eye bolts must be inserted outboard to inboard
replace as necessary. After compleside due to component interference.
tion, proceed to Steps 7-9.
• If a ride height adjustment was performed, re-torque is necessary, see Steps 7-9.
7. With the truck at the correct ride height, loosen the two (2) spring eye fasteners and four (4) rear
shackle bracket fasteners, see Figure 3.
FIGURE 3
STEERTEK NXT

Loosen Fasteners
DO NOT Remove

8. Re-torque all six (6) fasteners to~ 250 foot pounds of torque.
9. Remove the wheel chocks.
10. If after the above is completed and there is still clunking, contact Tech Services.
Refer any questions on this publication to Hendrickson Tech Services:
Toll-free U.S. and Canada
1.866.755.5968
Outside U.S. and Canada
1.630.910.2800

Ports Identification
truckports@hendrickson-intl.com
Technical Support
techservices@hendrickson-intl.com

1.630.910.2899

Additional Hendrickson
Product Information
www.hendrickson-intl.com

- - - - - - - - - - - - - - - - - www.hendrickson-intl.com

[ffillENDRICKSOR
Truck Commercial Vehicle Systems
800 South Frontage Road
Woodridge. IL 60517-4904 USA

17730-236 Rev A 10-13

1.866. 755.5968 (Toll-free U.S. and Canada)
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. Prciduct changes may have been made after the copyright date that are not reflected.
© 2013 Hendrickson USA1 L.L.C. All Rights Reserved

Printed in United Stoles of America