ARB RD94 User Manual

RD94

INSTALLATION GUIDE

ISUZU IFS, 17 SPLINE

Part No. 210294

Revision Date 11/11/03

Copyright © 2002 by ARB Corporation Limited

No liability is assumed for damages resulting in the use of the information contained herein.
ARB Air Locker Locking Differentials and Air Locker are trademarks of ARB Corporation Limited.
Other product names used herein are for identification purposes only and may be trademarks of their respective owners.

ARB 4x4 ACCESSORIES

Corporate Head Office

42-44 Garden St Tel: [phone]
Kilsyth, Victoria Fax: [phone]
AUSTRALIA
3137

Australian enquires [e-mail]
North and South American enquires [e-mail]
Other international enquires [e-mail]

www.arb.com.au

1 Introduction 3

1.1

Pre-Installation Preparation 3

1.2

2 Removing the Existing Differential 5

3 Bench Measurement 8

4 Installing the Air Locker 11

4.10

4.11

5 Installing the Air System 25

6 Mounting & Connecting the Electrical System 29

7 Testing & Final Assembly 34

8 Parts List 37

Tool-Kit Recommendations 4

2.1

Vehicle Support 5

2.2

Differential Fluid Drain 5

2.3

Removal of Axles and Differential 5

2.4

Marking the Bearing Caps 6

2.5

Checking the Current Backlash Amount 7

2.6

Removing the Differential Carrier 7

3.1

Measurement for Pre-Load Shimming 8

3.2

Calculation & Selection of Shims 10

4.1

Installing the Carrier Bearings 11

4.2

Mounting the Ring Gear 12

4.3

Drilling & Tapping the Bulkhead Port 13

4.4

Assembling the Differential Carrier 14

4.5

Modifying the Bearing Cap 16

4.6

Final Air Locker Assembly 17

4.7

Final Backlash Checking 18

4.8

Profiling the Seal Housing Tube 19

4.9

Setting up the Bulkhead Fitting 21
Bench Testing the Air Locker 23
Reinstalling the Axles 24

5.1

Mounting the Solenoid 25

5.2

Running & Securing the Air Line 27

5.3

Connection to the Bulkhead Fitting 28

6.1

Mounting the Actuator Switch(es) 29

6.2

Wiring the Actuator System 30

7.1

Leak Testing 34

7.2

Testing the Air Locker Actuation 34

7.3

Filling the Differential 35

7.4

Post-Installation Check List 36

8.1

Exploded Assembly Diagram 37

8.2

Itemized Parts List 38

1

2

1 Introduction

IMPORTANT :

BEFORE ATTEMPTING TO DISMANTLE YOUR VEHICLE FOR THIS

INSTALLATION, PLEASE READ THIS INSTALLATION GUIDE IN ITS

ENTIRETY, AS WELL AS ALL APPLICABLE SECTIONS OF YOUR

VEHICLE MANUFACTURER’S SERVICE MANUAL.

1.1 Pre-Installation Preparation

This booklet is to be used in conjunction with your vehicle
manufacturer’s service manual. ARB endeavors to account for every
possible variation in vehicle model when publishing its installation
guides, and guides are updated regularly as new model information
becomes available, however, the rapid and globally varied release of
some vehicles makes it difficult to insure that your vehicle model has
been accurately accounted for. In the case of any technical
discrepancies between this guide and your service manual, we
strongly advise that you adhere to the specifications and techniques
as documented in your service manual.

Although your ARB Air Locker comes complete with all the step by
step instructions you will need to supplement your vehicle
manufacturer’s service manual and install your new differential, ARB
recommends that you have your Air Locker installed by a trained
professional. Many ARB distributors around the world have been fully
instructed in Air Locker installations by ARB, and have gained a wealth
of experience and skill from years of performing similar installations.

Once you begin this installation your vehicle will be immobile until all
steps of the installation are complete. Make sure your Air Locker kit is
the correct model for your vehicle and that it contains all of the parts
listed on back cover of this booklet. Also be sure you have
appropriately equipped yourself with all the necessary tools, parts, and
materials to complete this installation (see section 1.2 Tool-Kit
Recommendations), and that you have allowed for an appropriate
amount of vehicle down time.

HINT : Place a mark inside each of the c symbols as

you complete each step. It is very important NOT to
miss any of the steps!

3

1 Introduction

1.2 Tool-Kit Recommendations

Below is a list of tools and supplies you may need to complete this
installation. Requirements for your vehicle may vary. Please consult your
vehicle service manual for additional recommendations.

1.2.1 Tools

c Standard automotive sizes (metric and/or imperial) of sockets,

wrenches, Alan keys, and drills.

c A dial indicator or other suitable measuring tool for checking ring &

pinion backlash.

c A standard automotive feeler gauge.
c A razor knife to cut the nylon tubing.
c A torque wrench. (See vehicle service manual for required torque

range.)

c A lubricant drain reservoir.
c Suitable measuring tools to measure a differential for pre-load

and/or backlash shimming. (See Section 3 Bench Measurement)

c A 11.2mm [7/16”] drill and ¼” NPT tap for bulkhead fitting

installation.

c An automotive bearing puller (2 jawed is recommended) or a

differential carrier bearing puller.

c A bearing press or arbor press.

1.2.2 Supplies

c Thread lubricant/sealant compound (e.g., LOCTITE #567)
c Thread locking compound (e.g., LOCTITE #272)
c Either a replacement gasket, or gasket sealant, for your differential

cover.

c A sufficient volume of differential oil to completely refill your

housing. (see the ARB Air Locker Operating and Service Manual
for recommended lubricants)

c A soap and water mixture to test for air leaks.
c Teflon paste.
c A selection of differential bearing shims to set-up pre-load and

backlash. (See section 3 Bench Measurement)

4

2 Removing the Existing Differential

2.1 Vehicle Support

c Safely secure the vehicle on a hoist. We recommend supporting

the vehicle on a chassis hoist to keep the differential area at a
convenient working height and to leave the wheels and axles free
to be rotated and removed.

c Once supported off the ground, release the parking brake and

leave the vehicle in neutral. Chock the wheels if necessary.

2.2 Differential Fluid Drain

c Clean around the differential drain plug to prevent dirt from entering

the differential.

c Position a fluid drain reservoir under the differential and loosen the

differential drain plug.

c Completely drain all differential fluid.

HINT : This is a good time to check for metal particles in

your oil and in the bottom of the housing which may
indicate a worn bearing or differential component.

2.3 Removal of the Axles and Differential

c Remove the front wheels from the vehicle.
c Disconnect the drive shaft from the flange of the differential.
c Remove the front axle assembly according to your vehicle

manufacturer service manual.

HINT : By removing the CV retaining clip from the left hand

hub assembly, removing the front right hand side
spindle/knuckle assembly and separating the mounting
bracket from the CV on the right hand side, it may be
possible to remove the front axle assembly without
removing the control arms.

NOTE : Rubber oil seals can be easily damaged. Support the

weight of the axle when extracting it across the edges
of the seals.

c Remove the differential housing from the axle case and secure it to

a workbench.

5

2 Removing the Existing Differential

2.4 Marking the Bearing Caps

c Using a pointed center punch, gently mark the bearing caps in a

way that will enable you to know which cap is ‘LEFT’ and which cap
is ‘RIGHT’, which way is ‘UP’ and which way is ‘DOWN’.
(Fig.1.)

HINT : Many installers choose to make one punch mark on

the left hand side of the left hand bearing cap and one
similar punch mark on the housing at close proximity to
the cap mark. The right hand side is then designated
with two punch marks on the right hand side of the cap
and two similar punch marks on the housing.

Figure 1.

6

2 Removing the Existing Differential

2.5 Checking the Current Backlash Amount

IMPORTANT:

This step is a precautionary measure recommended by ARB due to

the fact that some after market ring and pinion sets have been

manufactured to run with different backlash settings than those

specified by your vehicle manufacturer. Although ARB must

recommend you set backlash according to your service manual

guidelines, we also advise that you compare the backlash

measurements taken here to the recommended backlash settings in

your vehicle service manual. Measurements found to be outside of

your service manual recommendations may indicate the need to

deviate from those settings in order to achieve quiet running with a

good contact mark.

Refer to your vehicle service manual or your local authorised ARB

c Set a depth indicator on one of the ring gear teeth as in figure 2.

installer for more information.

Figure 2.

c While supporting the pinion gear by holding the drive shaft, rotate

the differential in both directions while observing the maximum
variation in depth from the indicator (i.e., the highest value minus
the lowest value). This value is referred to as the ring and pinion
backlash.

c Rotate the differential center 90° and measure again for accuracy.
c Record the average of all measurements.

2.6 Removing the Differential Carrier

c Remove the bearing caps from the differential housing.
c Carefully remove the differential carrier from the differential

housing.

7

3 Bench Measurement

3.1 Measurement for Pre-Load Shimming

When fitting an ARB Air Locker, the original bearing types are used on
both sides of the Air Locker, however, in order to reproduce a similar
backlash and pre-load to that of your existing differential,
measurements need to be taken so that the correct shim thickness
can be determined for each side.

c Secure the differential to a workbench.
c Remove the bolts that hold the ring gear in place.
c Using a plastic or copper hammer, tap in a circle around the ring

gear to separate it from the differential carrier.

c Remove the original tapered roller bearings and shims from the

differential carrier using a bearing puller. (Fig 3.)

NOTE : Keep the shims separated so that they can be

identified as to which end of the differential they came
from.

Figure 3.

HINT : Check the condition of the bearing for wear and

replace if necessary.

c Using a calliper or similarly accurate measurement method

(i.e., able to take accurate measurements within 0.04mm [0.0015”]),
measure the distance from the bearing shoulder to the ring gear
mounting face (shown as ‘A’ in Figure 4.) and record this
measurement as ‘A’.

8

3 Bench Measurement

c Measure the thickness of the shim pack removed from the ring gear

side of the differential carrier (shown as ‘B’ in Figure 4.).and record
this measurement as ‘B’.

c Measure the distance from the Air Locker bearing shoulder to the

ring gear mounting face (shown as ‘C’ in Figure 5.) and record this
measurement as ‘C’.

Figure 4.

Figure 5.

9

3 Bench Measurement

3.2 Calculation & Selection of Shims

The thickness of the shim pack required for the Air Locker (shown as
‘D’ in Figure 5.) can now be determined by substituting the
measurements taken into the following equation.

A + B – C = D

HINT : If your calculations are correct then the following

equation will also be true:

A + B – C – D = ZERO

To make a shim pack to match the measurement you calculated as ‘D’
you can:

§ remove shims from the shim pack you measured as ‘B’.

§ add some shims from the shim pack you removed from the right

hand side of the original differential to the shim pack you
measured as ‘B’.

§ supplement your original shims with shims purchased from your
vehicle manufacturer.

§ Use a universal shim kit available from most drive train
specialists.

NOTE : Never re-use any shims that are damaged or worn.

10

4 Installing the Air Locker

4.1 Installing the Carrier Bearings

c With the Air Locker well supported in an arbor press, apply a thin

film of high-pressure grease to the ring gear side-bearing journal,
and assemble the newly established shim pack (thickness ‘D’ in
Fig.5.) onto the bearing journal.

c Press a tapered roller bearing cone onto the bearing journal of the

differential carrier until the bearing seats firmly against the shim
pack.

NOTE : Never re-use any bearings that are damaged or worn.

c Invert the Air Locker and apply a thin film of high-pressure grease

to the seal housing side bearing journal.

c Press an original bearing cone onto the Air Locker bearing journal,

taking care not to damage the O-ring grooves. (Figure 6.)

Figure 6.

NOTE : Do not add any shims between the seal housing

bearing and the bearing seat.

11

4 Installing the Air Locker

4.2 Mounting the Ring Gear

c Apply a thin film of high-pressure grease to the ring gear shoulder

c Thoroughly clean any thread locking compound or other foreign

NOTE : Rubbing the ring gear mounting face with a flat oil

c Heat the ring gear to between 80 and 100°C (175 - 212°F) in an

of the Air Locker to prevent seizing.

matter from the holes of the ring gear, the threads of the ring gear
bolts, and the mating surfaces of the ring gear and the Air Locker
flange.

stone before installation will remove any high spots
around the threads.

oven or in hot water to slightly expand the gear and facilitate
assembly.

NOTE : NEVER HEAT GEARS WITH A FLAME! This could

damage the hardened surface of the gear and result in
premature wear or failure.

c Dry the ring gear with compressed air (if wet), paying particular

attention to the threaded holes.

c Install the ring gear onto the Air Locker by aligning the holes in the

flange with the tapped holes in the ring gear, then gently tapping it
around in a circle with a plastic or copper hammer.

NOTE : Avoid using the bolts to pull down the ring gear as

this puts excess strain on the bolts and the differential
flange.

c Apply a thread-locking compound to the thread of each ring gear

bolt before inserting it.

NOTE : Do not apply threading compound directly into the

threaded hole as this could prevent the bolt from
reaching its full depth.

c Tighten the ring gear bolts in a star pattern with a torque wrench

according to your vehicle manufacturer’s specified torque.

12

4 Installing the Air Locker

4.3 Drilling and Tapping the Bulkhead Port

A port must be drilled and tapped through the differential housing to
allow the seal housing tube through the housing to connect with the air
line from the air compressor.

c Mark a spot for the bulkhead port on the left hand (seal housing)

side toward the top of the differential housing that is in an area that
will be well clear of the ring gear, the differential, and any other
obstructions that may snag the seal housing tube (Fig.7.).

HINT : The mark shown in figure 7. should be copied as

closely as possible.

Figure 7.

Figure 8.

c Cover the drive pinion and axle tube areas with a rag to protect

them from metal filings.

c Drill through the housing square to the outside surface using an

11.2mm [7/16”] drill. (Fig.8.)

c Tap the hole from the outside using a ¼’’ NPT tapered pipe thread

tap.

c Remove any sharp edges from the hole that may chip-off and fall

into the housing.

c Very carefully remove rags and inspect with a service light inside

the housing to ensure no metal filings are left behind.

13

4 Installing the Air Locker

4.4 Assembling the Differential Carrier

c Place the bearing cup over the bearing cone on the seal housing

side (Fig 9.)

Figure 9.

c Slide the seal housing into place against the bearing cup (stepped

side out).

NOTE : The grooves in the bearing journal under the seal

housing, will house the O-rings in the final assembly
but they will not be installed now to avoid damage to
the O-rings.

NOTE : The shim pack cannot be installed at this time as the

required thickness (shown as ‘E’ in Figure 9.) has yet
to be determined.

c Hold the bearing cup in place on the ring gear side.

14

4 Installing the Air Locker

c Holding the assembled components in place at each end, insert

and hold the Air Locker into the differential housing with the seal
housing tube pointing straight out of the housing.

c Install one bearing cap on the ring gear side. The bearing cap on

the seal housing side will need to be drilled as clearance for the
seal housing tube.

NOTE : It is very important to make sure the punch marks

made on the differential housing while removing the
differential are matched to the punch marks on the
bearing cap. The bearing cap must be replaced
exactly as it was removed. (Refer to section 2.4)

c Install the bearing cap bolts finger tight.
c Push the Air Locker hard across to the ring gear side, and measure

the gap (end float) between the seal housing and the bearing bore
edge with a feeler gauge.

c Consult your vehicle manufacturer’s service manual to determine

the carrier bearing pre-load amount specified for your vehicle.

c Add the specified pre-load amount to the measurement taken with

the feeler gauge to determine a shim amount for ‘E’ in Figure 9.

PRE-LOAD + END FLOAT = SHIM PACK

c Select suitable shims from the supplied shim kit to make up a shim

pack of this thickness.

15

4 Installing the Air Locker

4.5 Modifying the Bearing Cap

c A hole must be drilled in the seal housing bearing cap for the seal

housing tube to pass through.

c Measure and mark a location on the bearing cap that would allow a

6.35mm [¼’’] hole to be drilled with 1mm [0.039”] clearance from
the edge of the hole and the machined bearing recess. (Fig.10.)

Figure 10.

NOTE : Take time and double check when taking your

1mm

measurements, as bearing caps are custom fitted to
the axle housing and cannot be replaced.

c Hold the bearing cap steady for drilling in a soft jawed vice clamp.

NOTE : Do not apply too much clamping pressure with the

vice. The bearing cap may be damaged.

c Using a pedestal drill, drill a 6.35mm [¼’’] hole through the bearing

cap where the position has been marked.

c Debur both ends of the drilled hole to remove any sharp edges.

16

4 Installing the Air Locker

4.6 Final Air Locker Assembly

c With the seal housing removed clean all parts of the differential

assembly. It is very important to make sure the seal housing
grooves are free from any contaminants (eg: water, dirt, metal
fillings, etc.)

c Lubricate the O-rings with oil (prior to assembly), then stretch them

over the bearing journal and release them into the grooves.

NOTE : Do not roll the O-rings onto the seal housing as this

will damage them.

c Place the bearing cups onto their respective bearing cones.
c Install the seal housing over the O-rings by gently applying a

downward twisting motion. This will allow the O-rings to gently
engage.

c Assemble the shim pack over the seal housing tube and onto the

seal housing spigot (Figure 9.).

c Point the seal housing tube straight out of the housing, hold the

shims, seal housing and tapered roller bearing cups in place, and
insert and hold the Air Locker into the differential housing.

c Install the bearing cap on the ring gear side.

NOTE : When installing the bearing cap be careful not to

damage the shims.

c Check to see if the bearing cap on the seal housing side fits over

the tube without fouling and fits properly in place.

NOTE : Do not forget to check the bearing caps are turned the

correct way around.

c Install all bearing cap bolts and torque to manufacturer’s specs.

17

4 Installing the Air Locker

4.7 Final Backlash Checking

c Set a depth indicator on one of the ring gear teeth as in

Figure 11.

c While supporting the pinion gear by holding the drive shaft, rotate

the differential in both directions while observing the maximum
variation in depth from the indicator (i.e. the highest value minus
the lowest value). This value is referred to as the ring and pinion
backlash.

c Rotate the differential center 90° and measure again for accuracy.

Figure 11.

c Refer to your vehicle service manual for the specified maximum

and minimum amounts of backlash. If the backlash is not within the
specifications then the differential will have to be removed and re­shimmed.

4.7.1 Re-Shimming the Backlash

NOTE : This step is only necessary when adjusting for

incorrect backlash.

c Remove the bearing caps.
c Remove the differential.
c To increase the amount of backlash, reduce the shim thickness ‘D’

(Fig.5.) and increase the shim thickness ‘E’ (Fig.9.) by the same
amount. Reverse this step to decrease the backlash.

c Remount the differential as before.
c Check backlash again as before.

18

4 Installing the Air Locker

4.8 Profiling the Seal Housing Tube

The seal housing tube will need a low profile that hugs the bearing cap
in order to ensure clearance with the axle case when reinstalled into
the axle assembly.

c Without using sharp, jagged tools such as pliers (usually your

hands are the best tool for this job), bend the seal housing tube so
that it closely follows the profile of the differential housing and
protrudes through the bulkhead port in the differential housing
(Fig.12. and Fig. 13.).

Figure 12.

Figure 13.

19

4 Installing the Air Locker

c Check that the contour of the tube will not interfere with the Air

Locker or the ring gear.

Figure 14.

NOTE : Check to ensure there is running clearance between

the cylinder cap of the Air Locker and the bearing
cap/differential housing (Fig.14.). If there is no
clearance, the bearing cap and the differential housing
may need to be ground down slightly until some
clearance exists.

NOTE : It is also a good idea to keep the tube away from the

bearing caps or any other part of the differential
casting as any contact due to vibration or shock may
wear the tube and eventually cause a leak.

20

4 Installing the Air Locker

4.9 Setting up the Bulkhead Fitting

c Trim the seal housing tube that is extended outside the differential

housing to approximately 20-25mm [0.8-1.0”] of extension using an
automotive brake line tubing cutter.

NOTE : Never use a hacksaw for trimming the steel tube as

this will leave metal fillings in the air system.

c Apply thread sealant to the threads of the bulkhead body.
c Screw the bulkhead body into the tapped hole, and tighten.
c Wipe the area clean of any excess thread sealant (inside and

outside of the housing).

c From the outside of the housing, assemble the small O-ring over

the top of the short length of seal housing tube protruding through
the bulkhead fitting.

c While holding the seal housing tube into the bulkhead fitting, insert

the small drilled end of the center compression nut over the
extended tube as shown in the assembly diagram (Fig. 15.), and
screw it into the bulkhead body, and lightly tighten.

NOTE : Be sure to insert the correct end of the center

compression nut into the bulkhead body. The thread
has been partially relieved on the bulkhead side of the
center compression nut to visually identify its
orientation. (Fig. 15.)

21

4 Installing the Air Locker

Figure 15.

NOTE : Excessive tightening of the center compression nut is

not necessary to form a good seal around the tube
and may damage the O-ring, the seal housing tube, or
the threads of the compression nut.

NOTE : Make sure the seal housing tube is all of the way into

the center compression nut while you are tightening
it.

c Again check that no part of the seal housing tube comes in contact

with the moving differential components. Less than 8mm [5/16”]
should be considered too little clearance. Gently bend the tube
away from moving parts if necessary.

22

4 Installing the Air Locker

4.10 Bench Testing the Air Locker

c To test the Air Locker; when 620kPa [90 PSI] shop air is applied to

the seal housing tube, the Air Locker should engage.

c Check all fittings and the seal housing for air leaks.
c Rotate the differential carrier by turning the pinion flange whilst

applying air pressure.

NOTE : An accurate way to test for air leaks is to fit a shut-off

valve to an air pressure gauge, once 620 KPA [90 PSI]
is reached shut the valve off, disconnect the air hose,
and watch to see if there is any drop in pressure, if so,
this will indicate an air leak. (Fig.16.)

Figure 16.

c If a leak is found to be present, spray a soap and water mixture

onto the bulkhead air fitting. Bubbles should appear at any leak
points.

NOTE : Do not spray this soapy mixture inside the differential.

c Check that leaky fittings have been adequately tightened.
c Disassemble, clean threads, and reapply thread sealant if leaking

persists.

c If a leak is found at the seal housing, remove the Air Locker and

carefully remove the seal housing assembly, and examine the O­rings. Be very careful with the O-rings and check for defects,
damage, wear, or presence of foreign material in the O-ring
grooves. Replace if necessary.

23

4 Installing the Air Locker

4.11 Reinstalling the Axles

c Reinstall the differential housing into the axle case using gasket

sealant where necessary.

c Reinstall the front axle assembly according to your vehicle

manufacturer’s service manual.

NOTE : Be careful not to damage the axle oil seals with the

spline of the axle.

c Reconnect the drive shaft onto the flange of the differential.
c Reassemble the brakes and wheels to the vehicle according to your

vehicle manufacturer’s service manual.

24

5 Installing the Air System

5.1 Mounting the Solenoid

5.1.1 Connection to an ARB Air Compressor (Fig.17.)

c Remove one of the 1/8” BSP plugs from its port in the compressor

tank.

c Apply Teflon paste to the nipple (1/8” X 1/8” BSP) and insert it into

the port and tighten.

c Apply Teflon paste to the free end of the nipple.
c Assemble the inlet port side of the solenoid (stamped with a ‘1’)

onto the nipple and tighten. The solenoid should be rotated into a
position that does not obstruct any other ports on the compressor
tank.

NOTE : The solenoid exhausts compressed air through the

center of the black retaining cap when the Air Locker
is disengaged. Make sure this orifice cannot be
obstructed.

c Apply Teflon paste to the threads of the 5mm push-in fitting and

assemble it into the solenoid outlet port (stamped “2”) and tighten.

ARB

Air Compressor

Figure 17.

25

5 Installing the Air System

5.1.2 Connection to an Alternate Air Source

For ease of installation, quality of air supply, and a high level of
dependability from your Air Locker(s), ARB strongly recommends use
of a genuine ARB Air Compressor, however, the Air Locker air system
can be operated on any alternate air source that meets each of the
following guidelines:

c Must supply a minimum of 85PSI [586kPa].
c The supply must never exceed 105PSI [724kPa].
c The Air source should have a tank capacity that enables it to

actuate the Air Locker(s) in one charge so that no hesitation
is experienced when locking one or two differentials.

HINT : A good way to insure that you have the necessary

capacity is to make sure you can engage, disengage,
and then re-engage your Air Locker(s) without the air
source having to regenerate (e.g., without the
compressor turning on to refill the tank).

c Must supply clean air, free of rust, dirt, water, or other foreign

matter.

c Must match the 1/8” BSP porting of the Air Locker solenoid.

c Mount solenoid within close proximity of the air supply and secure it

from the effects of vibration and shock.

c Connect the air supply to the 1/8” BSP inlet port of the solenoid

(stamped “1” on the solenoid body) using thread sealant.

IMPORTANT :

ARB cannot warrant your Air Locker(s) against damage caused

as a result of using an alternate air supply. If you have any

doubts as to the suitability of your air system to use in an Air

Locker system, consult your ARB distributor.

26

5 Installing the Air System

5.2 Running and Securing the Air Line

The path taken by the air line from your air source (i.e., compressor) to
your Air Locker is unique to your vehicle and the position of your air
source. Plan ahead carefully when running the air line and always
follow these guidelines:

c Account for axle travel when running the line from the axle to a

fixed point on the vehicle. Leave enough slack in the air line to
allow for maximum suspension travel in both directions.

c Avoid leaving large lengths of air line hanging underneath the

vehicle where they may get tangled on rocks, sticks, etc.

HINT : Cable tying the air line to one of your flexible brake

lines will account for axle travel and should help keep

c Run the air line all the way from the compressor to the differential

before trimming either end of the line to length. This will save
complications that may arise if the air line has to be removed.

your line from getting snagged.

c Make sure the line does not contact sharp edges or abrasive

surfaces that may damage the air line over time.

c Do not run the air line around tight bends that may kink the air line

and restrict or block the air flow.

c Keep the air line well away from your vehicle’s exhaust

components. Air lines will melt if subjected to extreme heat.

c Do not run more air line than necessary. Excess line volume

created when coiling the left over hose, using unusually large
diameter hose, etc., will increase drain on the compressor tank
resulting in the compressor running more often than needed.

c Support the air line by tying it back with cable ties wherever

possible.

c At the solenoid end of the air line, trim the line to length with a

sharp knife.

NOTE : To remove the air line from the push-in fitting; while

holding the flange of the fitting out, push the air line
into the fitting as far as possible, then press the flange
inward, then pull the air line free of the fitting.

c To attach the air line to the push-in fitting of the solenoid; insert the

line firmly into the fitting, pull outward on the flange of the fitting
while holding the line as far into the fitting as possible, and then
gently pull outward on the air line to clamp the line in place.

27

5 Installing the Air System

5.3 Connection to the Bulkhead Fitting

c Trim the air line to length using a sharp knife.
c Insert the support spring over the end of the air line - small end first.

(Fig.18.)

c Insert the outer compression nut over the air line.
c Insert the 5mm [0.197”] ferrule over the end of the air line. Leave

approx. 5mm of tubing between the ferrule and the end of the tube.

Figure 18.

c Insert the support tube all the way into the end of the air line.

HINT : If the support tube is too difficult to insert, place the

end of the air line into a cup of boiled water to soften

c Insert the tube end all the way into the center compression nut.

the tubing.

c Screw on the outer compression nut and tighten. The ferrule and

support tube are now permanently attached.

c Assemble the support spring over the outside of the outer

compression nut.

c Secure any loose sections of tube with a cable tie.

28

6 Mounting & Connecting the Electrical System

6.1 Mounting the Actuator Switch(es)

Air Locker actuator switch(es) can be easily panel mounted inside the
vehicle in a 21mm x 36.5mm [0.83” x 1.44”] rectangular cutout.

NOTE : Only attach the cover plate to the face of the switch

once the switch has been mounted and wired correctly
as the cover plates are designed to be difficult to
remove.

For reasons of safety and for ease of operation, the Air Locker
actuator switch(es) should be mounted in a location picked to best suit
the operator. Make sure you have taken the following points into
consideration:

c Switch(es) MUST be mounted and should never be allowed to

simply dangle from the wiring loom during vehicle use.

c Switch(es) should be within easy reach of the driver. Ideally, any

Air Locker switch should be able to be operated without physical
effort or distraction to the driver.

c Switch(es) should be mounted within the line of sight of the driver

so that switch position (‘ON’ or ‘OFF’) can be visually determined
by the rocker position and the illumination state.

c The position of the switch(es) should best eliminate any possibility

of accidental operation by the driver or one of the passengers.

c Switch cutout position(s) must be located in an area with a

minimum of 50mm [2”] of clearance behind the face of the cutout.

c Switch(es) should not be mounted where they will be exposed to

water (e.g., in the lower section of an inner door panel).

c ARB recommends that you apply the Air Locker Warning Sticker

(ARB part # 210101) within close visual proximity of the switch
location.

NOTE : If no adequate position can be found on existing

dashboard panels, a surface mounted bracket
(Fig.19.) may be purchased from your ARB Air Locker
distributor to suit 1, 2, or 3 switches.

29

6 Mounting & Connecting the Electrical System

Figure 19.

6.2 Wiring the Actuator System

6.2.1 Connection to an ARB Air Compressor

When wiring the Air Locker actuator switch(es) and solenoid(s) to an
ARB Air Compressor, all connections can easily be set up directly from
the supplied wiring loom. (Fig.20.)

NOTE : Refer to your ARB Air Compressor Installation Guide

for details on configuring your installation.

30

6 Mounting & Connecting the Electrical System

IDENTIFICATION

ARB AIR COMPRESSOR WIRING LOOM

Figure 20.

SWITCH

TERMINAL

Figure 21.

UP

31

6 Mounting & Connecting the Electrical System

6.2.2 Connection to an Alternate Air Source

When connecting the actuation switch to an alternate air source, the
switch(es) should be wired according to figures 22. and 23., depending
on whether one or two Air Lockers will be installed in the vehicle.

6.2.2.1 Single Air Locker System

c If only one Air Locker is to be installed in the system, the switch and

solenoid should be wired according to figure 22. regardless of
whether the Air Locker has been installed in the front or rear axle of
the vehicle.

c Attach the appropriate switch cover (i.e., ‘FRONT’ or ‘REAR’) to

the switch.

NOTE : Refer to Figure 21. for the correct switch terminal

identification and switch orientation.

SINGLE Air Locker SYSTEM

Figure 22.

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6 Mounting & Connecting the Electrical System

DUAL

SYSTEM

6.2.2.2 Dual Air Locker System

c If two Air Lockers are to be installed in the system, ARB

recommends that the switches and solenoids be wired according to
figure 23. For safety reasons, this configuration allows SOLENOID
2 to be actuated only if SOLENOID 1 is already on.

c Attach the “REAR AIR LOCKER” switch cover to SWITCH 1, and

the “FRONT AIR LOCKER” switch cover to SWITCH 2.

NOTE : Refer to Figure 21. for the correct switch terminal

identification and switch orientation.

c Configure SOLENOID 1 as the air line leading to the rear axle Air

Locker, and SOLENOID 2 as the air line leading to the front axle Air
Locker.

Air Locker

Figure 23.

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7 Testing & Final Assembly

7.1 Leak Testing

c With the vehicle parked and the engine off, turn the compressor on

and wait until the air system is fully charged.

NOTE : With the Air Locker(s) disengaged, the air source (i.e.,

compressor) should not have to recharge over time.
Intermittent recharging without Air Locker use usually
indicates a leak at the solenoid fittings or at the
compressor tank O-ring seal.

c Actuate the Air Locker(s).
c The compressor should not come on again for a period of at least

15min. Air system recharging within that time period would indicate
that a leak is present in the system.

NOTE : If an alternate air source (e.g., an air cylinder or a belt

driven air pump) is used instead of a compressor, the
air system will have to be leak tested with a pressure
gauge and a shut-off valve in series before the
solenoid input.

c If a leak is found to be present, spray a soap and water mixture

onto all air fittings in the system while the compressor is fully
charged. Bubbles should appear at any leak points.

c Check that leaky fittings have been adequately tightened.
c Disassemble, clean threads, and reapply thread sealant if leaking

persists.

7.2 Testing the Air Locker Actuation

To test that your air system, electrical system, and your Air Locker
differential is functioning correctly:

c Support the vehicle such that the wheels are free to rotate (e.g., on

axle stands, a chassis hoist, etc.)

c Leave the parking brake off, the transmission in neutral, and the Air

Locker switch ‘OFF’.

34

7 Testing & Final Assembly

c Turn the ignition to the ‘ON’ position (leaving the motor off). The

large illuminating symbol on the Air Locker switch cover should be
‘OFF’.

c Turn the compressor (or alternate air source) on to charge the air

supply up to its maximum pressure.

c Rotate one wheel by hand.
c The wheel should rotate freely and the opposite wheel should be

turning in the opposite direction without any resistance or
mechanical noise from within the differential.

c Turn the Air Locker switch to the ‘ON’ position. The illuminated

symbol on the switch cover should light up.

c Rotate the same wheel again.
c Both wheels should rotate together.
c Turn the switch off again.
c Rotate the same wheel.
c The wheels should again rotate in opposite directions.

7.3 Filling the Differential

NOTE : Consult the ARB Air Locker Operating & Service

Manual for recommendations on differential lubricant
specifications.

c Refill the differential until level with the filler hole.
c Rotate the differential center 2 full turns.
c Check the oil level and add oil if necessary.
c Replace filler plug (apply thread sealant to filler plug before

inserting if it is a threaded type plug).

c Wipe differential housing clean of any oil or grease that may collect

dirt or other abrasive particles.

35

7 Testing & Final Assembly

7.4 Post-Installation Check List

Now that the Air Locker installation has been completed, ARB
recommends that you take the time to complete the following check list
just to insure that you haven’t missed any of the vital steps.

c The air system has been leak tested.
c Thread locking compound was used on the ring gear bolts.
c All torque settings comply with the vehicle manufacturer’s specs

and were set with an accurate torque wrench.

c Differential fluid complies with ARB recommendations and has

been filled to the correct level.

c All air lines and wiring have been securely cable tied to resist

snagging.

c Switch(es) have been securely mounted within operator reach, yet

well away from danger of accidental engagement.

c Switch(es) function properly and illuminate to indicate that Air

Locker(s) are engaged.

c All operators who are to use the Air Locker have read, and fully

understand the ARB Air Locker Operating & Service Manual.

c The Air Locker Warning Sticker has been located within close

proximity of the actuator switch(es).

INSTALLATION PERFORMED BY:

DATE OF INSTALLATION:

ODOMETER READING:

ARB AIR LOCKER SERIAL No:

___________________________
___________________________
___________________________
___________________________

36

8 Parts List

8.1 Exploded Assembly Diagram

(See itemized parts list overleaf)

Figure 24.

37

8 Parts List

8.2 Itemized Parts List

(See exploded diagram figure 24.)

AIR LOCKER MODEL No. : RD94

ITEM # QTY

DESCRIPTION PART #

01 1 FLANGE CAP 021804
02 1 CLUTCH GEAR 050501
03 1 DIFFERENTIAL CASE 011905
04 4 PISTON SPRING 150102
05 3 CROSS SHAFT RETAINING PIN 120401
06 1 LONG CROSS SHAFT 061101
07 2 SHORT CROSS SHAFT 061201
08 1 PISTON (Polyamide) 040601
09 1 U-RING 160303
10 1 CYLINDER CAP 030901
11 2 SEAL HOUSING O-RING 160210
12 6 CYLINDER CAP RETAINING BOLT 200207
13 6 TAB WASHER – 6mm 150402
14 - TAPERED ROLLER BEARING

NOT SUPPLIED

15 1 SEAL HOUSING 081605
16 1 SHIM KIT SHK003
17 1 SPLINED SIDE GEAR 131007R
18 4 PINION THRUST WASHER 151107
19 4 PINION GEAR 140502R
20 1 SPIDER BLOCK 070502
21 1 SIDE GEAR 130907R
22 2 SIDE GEAR THRUST WASHER 151005

* 1 BULKHEAD KIT, O-RING TYPE, 3.5-5mm 170105
* 1 PUSH-IN FITTING,5mm (R1 5 1/8”) 170201
* 1 AIR LINE (5mm DIA X 6m LONG) 170301
* 1 NIPPLE, 1/8” BSP,MALE TO MALE 170501
* 1 SOLENOID VALVE 180103
* 1 ACTUATOR SWITCH 180209
* 1 SWITCH COVER (FRONT) 180210
* 10 CABLE TIE 180301
* 1 WARNING LABEL 210101
* 1 BUMPER STICKER 210102
* 1 OPERATING & SERVICE MANUAL 210200

* 1 INSTALLATION GUIDE 210294

* Not illustrated in exploded view.

38