Technical
Procedure

Trailer Suspension Systems
HT250US, HT300US and CXU

SUBJECT: Shock Mount Assembly Procedure

LIT NO: L725 
DATE: September 2018
REVISION: B

INTRODUCTION

The procedures in this document apply to shock bolt
replacement kits for Hendrickson HT™ SERIES HT250US,
HT300US and CONNEX™ CXU 23K/25K suspension
systems.
IMPORTANT: Hendrickson does not recommend
reusing fasteners. Bolt metal and threads
are stressed when tightened. Duplicating
clamp loads under torque is not assured
for used fasteners.
IMPORTANT: DO NOT apply additional lubricant
to fastener threads. Doing so will
reduce the friction between fastener
components which can lead to
overtightening, unpredictable clamp
loads and unreliable fastener
connections.
IMPORTANT: If the proper clamp load is not achieved,
shock failure may occur and may result
in damage to the suspension and/or its
components.
NOTICE: This procedure applies to
Hendrickson Genuine Parts used in
the performance of these procedures.
Hendrickson shock eyelets have a
solid inner metal insert that will
not crush under the specified clamp
loads.
For general safety and precautionary statements, refer
to Hendrickson literature number T12007, available at
www.Hendrickson-intl.com/TrailerLit.
For assistance in the United States and Canada, call
Hendrickson Trailer Technical Services at 866-RIDEAIR
(743-3247) or e-mail HTTS@Hendrickson-intl.com.

SHOCK MOUNT BOLT REPLACEMENT

Shock mount bolt kits can include replacement parts for
lower or both shock mount assemblies. These include
steps for assembling fasteners for both upper and lower
shock mounting brackets.
REMOVING SHOCK
1. If applicable, remove both the upper and lower
shock bolt hardware and the shock absorber.
2. Discard removed bolt(s) and related hardware.
UPPER SHOCK MOUNT BOLT REASSEMBLY
When replacing a shock, it is usually best to assemble
the shock to the upper mounting bracket first.
1. Insert the 31/4-inch shock bolt through the shock.
2. Thread the lock nut onto the upper shock mount
bolt.
NOTE: Do not torque bolts until both upper and lower
shock mounts are assembled.
3. Hold upper nut with 11/8-inch wrench and tighten
the upper shock bolt to 225±10 ft. lbs. (300±10
Nm) of torque.
4. Visually check all components to ensure fasteners
are tight.

LOWER SHOCK MOUNT REASSEMBLY
Use this procedure to install the lower shock mount
hardware (Figure 1).

6. Reaching through the rear of the suspension beam,
slide the third hardened flat washer (supplied with
the service parts kit) over the threads of the lower
shock bolt (Figure 1).
7. Thread the new torque-prevailing nut onto the
threads of the bolt.

Original

Spacer

8. Hand tighten the lower shock bolt.
NOTE: If the threads were drilled out, hold the
torque-prevailing nut with a 11/8-inch wrench
while tightening with tools.

Drilled

Lower shock
mount TORQ-RITE
shear-type bolt:
3
/4"-10 x 71/4"
Hardened
flat washers

Lower shock mount
block assembly
on inside of
suspension beam

New 3/4"-10
lock nut and
hardened
flat washer
(if required)

Figure 1: Lower shock bolt assembly

1. Inspect threads on the existing lower shock bolt
and lower shock mount block assembly (Figure 1).
If the threads are undamaged, skip to Step 3.
NOTE: Step 2 is required for suspensions built prior to
1999 with a 3/4"-16 x 51/4" lower shock bolt. It is
also required if the bolt broke in the nut during
removal.

Figure 2: TORQ-RITE® shear-type hex-head bolt

9. Using a Torx E20 ¾-inch drive socket and ¾-inch
impact wrench, tighten the TORQ-RITE sheartype hex-head bolt until the shear head feature
separates from the bolt head as shown in Figure 2.
This will occur at 225±10 ft. lbs. (300±10 Nm).
10. Visually check all components to ensure fasteners
are tight.
11. Discard any unused parts.

2. Using a 3/4-inch drill bit, drill out the broken bolt or
threads in the original nut (Figure 1).
3. Assemble the new 3/4"-10 x 71/4" TORQ-RITE sheartype hex-head bolt (Figure 2) onto the shock with
two harden flat washers and spacer as shown in
(Figure 1). New fastener hardware is supplied with
the service parts kit.
4. Insert threaded end of the bolt into the lower shock
mount block assembly.
5. If the threads of the lower shock mount block
assembly were not drilled out, skip the next two
steps.

Call Hendrickson at 866.RIDEAIR (743.3247) for additional information.
TRAILER COMMERCIAL VEHICLE SYSTEMS
2070 Industrial Place SE
Canton, OH 44707-2641 USA
866.RIDEAIR (743.3247)
330.489.0045 • Fax 800.696.4416

www.hendrickson-intl.com
L725 Rev B 09-18 ECN 31723

Rev A 01-18 ECN 30712

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

Hendrickson Mexicana
Circuito El Marqués Sur #29
Parque Industrial El Marqués
Pob. El Colorado, Municipio El Marqués,
Querétaro, México C.P. 76246
+52 (442) 296.3600 • Fax +52 (442) 296.3601

12-99

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.

© 2018 Hendrickson USA, L.L.C. All Rights Reserved

Printed in United States of America