Interior Faceplate

R-017521-11

1

3

Composite Enclosure Box

R-017521-14

1

4

Stainless Steel Enclosure Box

R-017521-15

1

a

2" Liquid Filled Gauge with Straight Fitting for LC- NSI, SSI, LSI, RSI or ASI

R-017521-08

1

5

b

2" Liquid Filled Gauge with 90-Degree Fitting for
LC-UCO, USO, MSO, MCA, LCO, LSO, RCO, RSO, ACO or ASO

R-017521-09

1

6

Pneumatic Push / Pull Valve

R-017521-10

1

7

Pneumatic Air Toggle Switch

R-017521-06

1

8

Regulator

R-017521-04

1

9

Solenoid Valve

R-017521-12

1

10

Electric Override Switch

R-017521-05

1

Replacement Parts List

16

OM-H817

LC Auxiliary Lift Axle Control Kits

11

12

13

14

15

17

18

19

ITEM

DESCRIPTION

16

PART NUMBER

QTY.

11

Lift Axle Slave Assembly

R-017521-18

1

12

Slave Mounting Bracket

R-017521-03

1

13

Air Pilot Valve Slave Sub-Assembly (Ride Springs)

R-017521-17

1

14

Air Pilot Valve Slave Sub-Assembly (Lift Springs)

R-017521-16

1

15

Quick-Exhaust Valve

R-017521-02

1

16

Pressure Protection Valve

R-017521-13

1

17

Reverse Lift & Lock Valve Assembly

R-017519-00

1

18

Reverse Down & Lock Valve Assembly

R-017520-00

1

19

Reverse Caster Valve Assembly

R-017518-00

1

OM-H817

17

Replacement Parts List

LC Auxiliary Lift Axle Control Kits
SECTION 8

Frequently Asked Questions
NOTE

All brake plumbing installations must adhere to FMVSS-121 regulations. Modification to a vehicle’s pneumatic system may alter its compliance to FMVSS-121 regulations.

QUESTION

RESPONSE

1

Where do I install my Hendrickson
air kit control panel?

The Hendrickson air kit product line is available for Inside- and Outside-Mounting.
Your particular application will be dictated by regulations in your state(s) of
operation.

2

My axle goes down after the truck
is shut down and it raises the entire
chassis. Can I make the axle stay in
the up position?

All Outside-Mounted LC series air kits (excluding MCA, MSO) are set up to lower the
axle to the down position when power is off. This symptom is an indication that the
in-cab Electric Override Switch is in the LIFT position and the Outside-Mounted master
control's push / pull valve is in the LOWER position. Therefore, move the push / pull
valve to the LIFT position to immediately lift the axle.
There are two (2) options to have the lift axle stay in the UP position without having
to exit the vehicle to operate an Outside-Mounted control.
Option 1: With your current air kit installed, rewire the +12v DC power source from the
switch. Connect it to the battery instead of accessory ON power. Amp draw on battery
is 0.58a to 7 watts.
Option 2: Install the LC-MCA air control, which is designed to default to the lifted
position with the power off. Changing to the LC-MCA will keep the axle up when the
vehicle is shut down.

3

Can I plumb my air kit in-line with
my ride height control valve?

Complete vehicle assessment should be conducted considering primary suspension
load share and vehicle handling performance. Specific instances can be reviewed by
Hendrickson Technical Service Department.

4

At what pressure should the
regulator be set?

Typically 70‑120 psi. – All new lift axle and air control installations should be verified
at a certified scale to determine correct pressures for vehicle loading. See air
pressure load charts in the applicable Hendrickson Auxiliary Lift Axle Owner’s Manual
Literature No. OM-H754 (Steerable) or Literature No. OM-H757 (Non‑Steerable).
Improper vehicle loading can cause handling irregularities and component damage.

5

How do I identify my air kit?

For Inside-Mounted air kits,the identification tag is located on the back of the control
panel. For Outside-Mounted air kits, the identification tag is located on the inside of
the lid.

6

Why do steerable suspensions
require auto lift in reverse?

Due to the positive caster angle built into Hendrickson steerable lift axles they are
designed to track with the vehicle in forward motion. Moving in reverse the wheels
will lock sideways and scrub the tires imparting high stress on the axle and leading
to potential damage.

7

How does the reverse locking
option engage?

The reverse locking option requires both an axle with the lock straight optional
components installed and an air control specified to control the lock straight. The
relay in the air control kit is wired to sense the activation of the reverse lights when
the vehicle transitions to reverse gear. The relay will energize the lift axle control
solenoid to switch the valve to lift mode.

9

Why does my pressure gauge show
ride pressure when axle is raised?

The gauge will show a constant value for pressure dialed into the regulator. This
makes technicians and operators aware of both ride pressure and stored pressure,
which can cause severe personal injury and component damage.

Frequently Asked Questions

18

OM-H817

LC Auxiliary Lift Axle Control Kits
SECTION 9

Troubleshooting Guide
LC AUXILIARY LIFT AXLE CONTROL KITS
TROUBLESHOOTING GUIDE
PROBLEM

POSSIBLE CAUSE
Non-functioning master push / pull valve

Replace push / pull valve with Part Number R-017521-10.

Non-functioning master solenoid valve

Replace solenoid valve with Part Number R-017521-12.

Non-functioning relay

Replace electric override switch with Part Number R-017521-05.

Solenoid on master control is not being
energized

Connect one black wire to vehicle ground and the second black wire to backup
light power wire or Terminal 30 on supplied relay.

Kinked, pinched, or broken air line
Automatic lift does Supply air pressure insufficient to operate lift
not function
mechanism

Suspension does
not carry rated
load

OM-H817

Replace air line.
Verify that you are receiving 100 psi minimum at the master control; Use
calibrated gauge at supply line inlet.

Non-functioning Quick-Exhaust Valve on slave

Replace Quick-Exhaust Valve with Part Number R-017521-02.

Exhaust port(s) on master and / or slave are
plugged

Remove obstruction.

Air kit not properly plumbed

Confirm that air kit is plumbed per Figure 5-1, Plumbing & Wiring Diagram in
this publication.

Non-functioning master or slave control

Contact Hendrickson Warranty Department.

Non-functioning master push / pull valve

Replace push / pull valve with Part Number R-017521-10.

Non-functioning pneumatic toggle switch

Replace toggle switch with Part Number R-017521-06.

Non-functioning relay

Replace electric override switch with Part Number R-017521-05.

Electric override switch not properly installed

Confirm that the electric override switch is installed per this manual.

Kinked, pinched, or broken air line

Replace air line.

Supply air pressure insufficient to operate lift
mechanism

Verify that you are receiving 100 psi minimum at the master control; Use
calibrated gauge at supply line inlet.

Manual lift does
not function (push Non-functioning Quick-Exhaust Valve on slave
/ pull valve or
Exhaust port(s) on master and / or slave are
toggle switch)
plugged

Slow lift or lower
times

CORRECTION

Replace Quick-Exhaust Valve with Part Number R-017521-02.
Remove obstruction.

Air kit not properly plumbed

Confirm that air kit is plumbed per the plumbing schematic in this manual.

Non-functioning master or slave control

Contact Hendrickson Warranty Department.

Regulator turned down too low

Increase air pressure at regulator until desired load is carried at wheels.

Truck in reverse gear

Place transmission in forward gear or neutral.

Solenoid valve is energized

Place transmission in forward gear or neutral and confirm push / pull valve or
toggle switch are in LOWER mode (Excluding LC-NSI, RSI).

Insufficient air flow or volume being delivered
to master control

Confirm supply line size is 3⁄8" OD; increase air reservoir capacity.

Insufficient air flow or volume being delivered
to the air springs

Conform air line size is 3⁄8" to ½" going to air spring air lines.

Insufficient air pressure in ride springs

Increase pressure in ride springs by increasing regulator setting. Check pressure
in ride springs at air spring inlet.

Supply air pressure insufficient to operate lift
mechanism

Verify that you are receiving 100 psi minimum at the master control; Use
calibrated gauge at supply line inlet.

Kinked, pinched or broken air line

Replace air line.

Non-functioning air kit control panel

Contact Hendrickson Warranty Department.

Incorrect lift axle ride height

Contact Hendrickson Technical Service Department.

19

Troubleshooting Guide

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
H817 Rev A 04-19

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.

Printed in United States of America