ARB RD131 User Manual

INSTALLATION GUIDE

RD131

TOYOTA 8” IFS, 50mm BRNG

Part No. 2102131

Revision Date 02/10/06

Copyright © 2006 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 enquiries [e-mail]
North & South American enquiries [e-mail]
Other international enquiries [e-mail]

1

Table of Contents:

1 Introduction 3

Pre-Installation Preparation 3

1.1

Tool-Kit Recommendations 4

1.2

2 Removing the Existing Differential 5

Vehicle Support 5

2.1

Differential Fluid Drain 5

2.2

Removing the Axles & Differential 5

2.3

Marking the Bearing Caps 6

2.4

Checking the Current Backlash Amount 6

2.5

Removing the Differential Carrier 7

2.6

3 Bench Measurement 8

Approximate Backlash Shimming 8

3.1

Calculation & Selection of Shims 9

3.2

4 Installing the Air Locker

4.10

4.11

5 Installing the Air System

6 Mounting & Connecting the Electrical System

7 Testing & Final Assembly

8 Parts List

Installing the Carrier Bearings 11

4.1

Mounting the Ring Gear 11

4.2

Assembling the Seal Housing 12

4.3

Calculation & Selection of Pre-Load Shims 13

4.4

Drilling and Tapping the Bulkhead Port 14

4.5

Drilling the Diff Housing for Seal Housing Tube 15

4.6

Final Backlash Checking 16

4.7

Profiling the Seal Housing Tube 17

4.8

Setting Up the Bulkhead Fitting 19

4.9

Bench Testing the Air Locker 21
Reinstalling the Differential and Axles 22

Mounting the Solenoid 23

5.1

Running & Securing the Air Line 25

5.2

Connection to the Bulkhead Fitting 26

5.3

Mounting the Actuator Switch(es) 27

6.1

Wiring the Actuator System 28

6.2

Leak Testing 32

7.1

Testing the Air Locker Actuation 32

7.2

Filling the Differential 33

7.3

Post-Installation Check List 34

7.4

Exploded Assembly Diagram 35

8.1

Itemized Parts List 36

8.2

11

23

27

32

35

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  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

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

wrenches, Allen keys, and drills.

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

pinion backlash.

 A standard automotive feeler gauge.
 Automotive brake tubing cutters to cut the copper tubing.
 A razor knife to cut the nylon tubing.
 A differential housing spreader, to facilitate removal of the carrier.
 A torque wrench. (See vehicle service manual for required torque

range.)

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

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

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

installation.

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

differential carrier bearing puller.

 A bearing press or arbor press.

1.2.2 Supplies

 Thread lubricant/sealant compound for pressure fittings (e.g.,

LOCTITE #567 Teflon paste)

 Thread locking compound (e.g., LOCTITE #272)
 Either a replacement gasket, or gasket sealant.
 A sufficient volume of differential oil to completely refill your

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

 A soap and water mixture to test for air leaks.
 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

 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.

 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

 Clean around the differential cover flange seal to prevent dirt from

entering the differential.

 Position a fluid drain reservoir under the differential.
 Remove fluid drain plug to empty all differential oil.

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

your oil which may indicate a worn bearing or
differential component.

2.3 Removing the Axles & Differential

 Disconnect the stub axles from the differential assembly according

to your vehicle’s service manual..

 Disconnect the drive shaft from the flange of the drive pinion.
 Remove the entire differential assembly from the vehicle.

NOTE : The differential housing is heavy and quite difficult to

handle when covered in oil. Do not drop it!

 Secure the assembly to a work bench, and remove the cover plate.
 Remove the axle assembly from the side of the differential housing.

IMPORTANT :

Collision damage or heavy off-road use of your vehicle in the past may

have resulted in some degree of bending in the axle. Any misalignment

of the axle tube may result in excessive wear and/or failure of your

differential and stub shaft. ARB strongly recommends that you have

your axle assembly inspected for concentricity and straightness before

installing your Air Locker.

5

2 Removing the Existing Differential

2.4 Marking the Bearing Caps

 Using a pointed center punch, gently mark the differential housing

and the bearing caps in a way that will enable you to correctly
position the cap during reassembly. (Fig.1.)

Figure 1.

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 authorized

ARB installer for more information.

6

2 Removing the Existing Differential

 Set a depth indicator on one of the ring gear teeth as in Figure 2.

Figure 2.

 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.

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

2.6 Removing the Differential Carrier

IMPORTANT:

Spreading the differential housing with a differential case

spreader is a step which is critical to set up bearing pre-load

when a differential is installed. Improper pre-load will result in

undue bearing wear, increased stresses in the differential carrier,

increased running noise, and ultimately, ring and pinion gear

damage.

 Unbolt and remove the bearing caps.
 Carefully spread the differential housing just enough to remove the

differential carrier (Refer to your vehicles service manual).

NOTE : Never spread the housing more than 0.5mm [0.020”]

 Once the housing has been adequately spread, the differential may

be removed by pulling forward on the differential carrier.

7

3 Bench Measurement

3.1 Approximate Backlash Shimming

In order to reproduce a similar pre-load and ring and pinion backlash
in your Air Locker to that of your original differential, measurements
need to be taken so that a shim thickness can be calculated.

 Secure the original differential to a work bench.
 Remove the bolts that hold the ring gear in place.
 Using a plastic or copper hammer, tap in a circle around the ring

gear to separate it from the differential carrier.

 Remove the original bearings and shims from the differential center

using a bearing puller.

NOTE : Keep the bearings and shims separated so that they

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

 Examine the bearing cups and cones from Fig. 3. for damage or

wear and, if necessary, discard them and replace with the same
size and type of bearings.

Figure 3.

 Using a caliper or similarly accurate measurement method

(i.e., able to take accurate measurements within 0.04mm [0.0015”]),
measure the distance from the shoulder of the bearing journal to
the ring gear mounting face (shown as ‘A’ in Fig.3.) and record this
measurement as ‘A’.

8

3 Bench Measurement

 Measure the thickness of the factory shim removed from the end of

the differential carrier (shown as ‘B’ in Fig.3.) and record this
measurement as ‘B’.

Figure 4.

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

ring gear mounting face (shown as ‘C’ in Fig.4.) and record this
measurement as ‘C’.

3.2 Calculation & Selection of Shims

Ideally, the measurement you recorded as ‘C’ from the Air Locker
differential will closely match ‘A’ on the existing differential (within

0.1mm [0.004”] ) and then the factory shim can be reused on this end,
however, quite often these measurements will vary slightly between
one factory differential and the next.

If this is the case you must create a new shim pack thickness by using
the measurements you recorded earlier to find a desired measurement
for ‘D’ in Fig. 4.

Use the following calculation:

A + B – C = D

(Replacement Shim Pack)

9

3 Bench Measurement

HINT : If your calculations are correct then the following

equation will also be true:

A + B – C – D = ZERO

 Create a shim pack to match the thickness calculated as ‘D’.
To achieve the desired shim thickness you can:

• Machine down the factory shim thickness.

• Add shims between the factory shim and the bearing cup.

HINT : A selection of shims of this size have been supplied

with your Air Locker kit.

• Purchase new factory shims at the desired thickness.

• Use a universal shim kit available from most drive train

specialists.

• Add small amounts of shim between the bearing cone and the
bearing seat.

NOTE : NEVER machine the Air Locker.

10

4 Installing the Air Locker

4.1 Installing the Carrier Bearings

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

film of high pressure grease to both bearing journals.

 Press one of the tapered roller bearing cones onto one of the

bearing journals of the Air Locker until the bearing seats firmly
against the bearing journal shoulder.

 Invert the Air Locker and press the second bearing cone onto the

opposite bearing journal until the bearing seats firmly against the
bearing journal shoulder.

NOTE : Never re-use any bearings which are damaged or

worn.

4.2 Mounting the Ring Gear

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

of the Air Locker to prevent seizing.

 Thoroughly clean any thread locking compound or other foreign

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.

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

stone before installation will remove any high spots
around the threads

.

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

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.

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

attention to the threaded holes.

 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.

11

4 Installing the Air Locker

 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.

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

according to your vehicle manufacturer’s specified torque.

4.3 Assembling the Seal Housing

 Make sure the grooves and airway of the seal housing are clean

and free from any contaminants (e.g. water, dirt, metal filings, etc.).

Figure 5.

 Inspect the seal housing O-rings (supplied) for dirt, damage or

other conditions which might cause leaks.

 Generously lubricate the O-rings with oil prior to assembly, then

insert them into the grooves of the seal housing.

NOTE : When assembling the O-rings, be careful not to leave

them twisted when seated in the grooves as this could
cause excessive wear and leakage.

12

4 Installing the Air Locker

 Lubricate the seal housing running surface on the Air Locker carrier

with oil. Assemble the bearing cup onto the left-hand side of the Air
Locker.

NOTE : No shims should be assembled onto the seal housing

at this time. The bearing cup should sit directly

 Carefully install the seal housing by sliding it all of the way onto the

bearing journal with a gentle twisting motion. This will allow the O­rings to engage gently.

4.4 Calculation & Selection of Pre-Load Shims

In order to pre-load the tapered roller bearings in your Air Locker,
measurements need to be taken so that a value can be calculated for
the shim thickness ‘E’ in Figure 5.

against the seal housing.

 Hold the bearing cup and shim pack ‘D’ (Fig.4.) in place, and insert

the Air Locker into the housing.

 Push the Air Locker hard

across against the bearing and shim pack
‘D’, and measure the gap between the end of the seal housing
assembly and the bearing seat of the differential housing with a
feeler gauge.

NOTE : This ‘end float’ measurement determines the shim

thickness necessary to achieve ‘neutral pre-load’.
Adding more shim than this measurement becomes
the actual ‘pre-load’.

 Consult your vehicle manufacturer’s service manual to determine

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

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

the feeler gauge to determine a shim amount for ‘E’ in Figure 5.

PRE-LOAD + END FLOAT = SHIM PACK

 Select suitable shims from the shim kit supplied with your Air

Locker to make up a shim pack of this thickness. (Refer to section

3.2 for methods of shim adjustment).

 The seal housing will have to be removed in order to add shim pack

‘E’. Ensure that the seal housing is re-installed correctly.

13

4 Installing the Air Locker

4.5 Drilling and Tapping the Bulkhead Port

An air line port must be drilled and tapped through the differential
housing to mount the bulkhead fitting into.

 Mark a spot on the exterior of the differential cover plate in the

position shown in Figure 6. (i.e., toward the bottom in the center of
the flat area that will be accessible from the outside and clear of all
moving components inside).

Figure 6.

 Secure the differential cover plate to a work bench.
 Drill an 11.2mm [7/16”] diameter hole through the differential

housing square to the outside surface.

 Tap the hole from the outside using ¼”NPT thread tap.
 Remove any sharp edges that may chip off from around the hole

and fall into the housing.

 Thoroughly clean the cover plate to remove any filings from drilling.

14

4 Installing the Air Locker

4.6 Drilling the Diff Housing for Seal Housing Tube

A hole must be drilled through a tab inside the diff housing to cable tie
the seal housing tube to for support.

 Mark a spot on the tab as shown in Figure 7.
 Cover the drive pinion with rags to protect it from any metal filings

and drill a 5mm hole through the tab (Fig. 8.)

 Debur the hole and remove the rags, ensuring not to get any metal

filings in the drive pinion.

Figure 7.

Figure 8.

15

4 Installing the Air Locker

4.7 Final Backlash Checking

 Spread the differential housing again (Refer to section 2.6).
 Hold shim packs ‘D’ (Refer to section 3.2) and ‘E’ (Refer to section

4.4) in position on the Air Locker.

 Reinstall the Air Locker into the differential housing, ensuring that

the seal housing is positioned so that the tube will clear the bearing
cap.

NOTE : If the carrier is too difficult to install with the added

 Place the bearing caps in place to align the seal housing.
 Relieve all tension on the housing spreader.

shim pack then the spreader tension may need to be
increased. Do not spread the housing more than

0.50mm [0.020”].

 Tighten all bearing cap bolts with a torque wrench to the torque

specified in your vehicle manufacturer’s service manual.

 Set a depth indicator on one of the ring gear teeth as in Fig. 9.
 While supporting the pinion gear by holding the drive flange, 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.

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

Figure 9.

 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.

16

4 Installing the Air Locker

4.7.1 Re-Shimming the Backlash

NOTE : This step is only necessary when adjusting for

 Reapply the spreader to the differential housing.
 Remove the bearing caps.
 Remove the differential.
 To increase the amount of backlash, reduce the shim thickness ‘D’

(Fig.4.) and increase the shim thickness ‘E’ (Fig.5.) by the same
amount. Reverse this step to decrease the backlash.

 Remount the differential as before.
 Release spreader tension.

incorrect backlash.

 Check backlash again as before.

4.8 Profiling the Seal Housing Tube

 Without using sharp, jagged tools such as pliers (your hands are

the best tool for this job), bend the seal housing tube so that it runs
between the bearing cap and diff housing, around the ring gear,
and points out of the diff inline with the position of the bulkhead port
in the cover plate. Assure that the tube adequately clears all
moving parts of the differential assembly. Less than 10mm [3/8”]
should be considered too little clearance (refer to Figures 10. & 11.
for suggested tube shape).

 Using the supplied cable tie, attach the seal housing tube to the

housing through the previously drilled hole. Trim the cable tie to
length. This will support the tube from vibration.

Figure 10.

17

4 Installing the Air Locker

Figure 11.

 Install the differential cover plate onto the differential housing using

2 bolts (hand tight only) to hold the cover in place.

 Rotate the differential center a few turns to make sure the tube is

not contacting the center at any point.

 Mark a position on the protruding length of tube approximately 8mm

[5/16”] from the bulkhead port (Fig. 12.).

Figure 12.

18

4 Installing the Air Locker

 Remove the cover plate.
 Using an automotive brake line tubing cutter, trim the tube at the

position marked.

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

this will leave metal filings in the air system.

 Reinstall the differential cover onto the differential housing by firstly

inserting the free end of the seal housing tube through the bulkhead
port from the inside. No gasket sealant or gasket is required at this
time.

 Install 2 bolts hand tight to hold the cover in place.

4.9 Setting Up the Bulkhead Fitting

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

outside of the housing).

 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.

 Insert the small drilled end of the center compression nut over the

extended tube as shown in the assembly diagram (Fig.13.), 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.13.)

19

4 Installing the Air Locker

Figure 13.

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.

20

4 Installing the Air Locker

4.10 Bench Testing the Air Locker

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

the seal housing tube, the Air Locker should engage.

 Check all fittings and the seal housing for air leaks.
 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 (ARB part # ALTG01).
Once 620 KPA [90 PSI] is reached close the valve,
disconnect the air hose, and watch to see if there is any
drop in pressure. If so, this will indicate an air leak.
(Fig.14.)

Figure 14.

 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.

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

persists.

 If a leak is found at the seal housing, carefully remove the seal

housing assembly and examine the O-rings. 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.

21

4 Installing the Air Locker

4.11 Reinstalling the Differential and Axles

 Apply gasket sealant (or a gasket) to the differential cover plate and

reinstall it onto the housing.

 Tighten all cover bolts according to the torque specifications in your

vehicle manufacturer’s service manual.

 Replace the stub axle seals if necessary.
 Reassemble and reinstall the differential assembly according to

your vehicle service manual.

NOTE : Be careful not to damage the stub axle oil seals when

inserting the axles.

 Reinstall the driveshaft.

22

5 Installing the Air System

5.1 Mounting the Solenoid

5.1.1 Connection to an ARB Air Compressor (Fig.15.)

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

tank.

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

the port and tighten.

 Apply Teflon paste to the free end of the nipple.
 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.

 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 15.

23

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
of a genuine ARB Air Compressor, however, the
can be operated on any alternate air source that meets each of the
following guidelines:

 Must supply a minimum of 85PSI [586kPa].
 The supply must never exceed 105PSI [724kPa].
 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 reengage your Air
Locker(s) without the air source having to
regenerate (e.g., without the compressor turning
on to refill the tank).

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

matter.

Air Locker(s), ARB strongly recommends use

Air Locker air system

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

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

from the effects of vibration and shock.

 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.

24

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
source. Plan ahead carefully when running the air line and always
follow these guidelines:

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

 Avoid leaving large lengths of air line hanging underneath the

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

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

Air Locker is unique to your vehicle and the position of your air

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

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

lines will account for axle travel and should help keep
your line from getting snagged.

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

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

surfaces that may damage the air line over time.

 Do not run the air line around tight bends which may kink the air

line and restrict or block the air flow.

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

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

 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.

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

possible.

 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.

 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.

25

5 Installing the Air System

5.3 Connection to the Bulkhead Fitting

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

(Fig.16.)

 Insert the outer compression nut over the air line.
 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 16.

 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

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

the tubing.

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

support tube are now permanently attached.

 Assemble the support spring over the outside of the outer

compression nut.

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

26

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:

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

simply dangle from the wiring loom during vehicle use.

 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.

 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.

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

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

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

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

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

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

 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.17.) may be purchased from your ARB Air Locker
distributor to suit 1, 2, or 3 switches.

27

6 Mounting & Connecting the Electrical System

Figure 17.

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.18.)

NOTE : Refer to your ARB Air Compressor Installation Guide

for details on configuring your installation.

28

6 Mounting & Connecting the Electrical System

ARB AIR COMPRESSOR WIRING LOOM

Figure 18.

NOTE : ARB wiring loom #180405 shown. Consult the

compressor installation guide for the diagram to suit
your compressor model.

SWITCH

IDENTIFICATION

TERMINAL

Figure 19.

UP

29

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 20. and 21.,
depending on whether one or two Air Lockers will be installed in the
vehicle.

6.2.2.1 Single Air Locker System

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

solenoid should be wired according to Figure 20. regardless of
whether the Air Locker has been installed in the front or rear axle of
the vehicle.

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

switch.

NOTE : Refer to Figure 19. for the correct switch terminal

identification and switch orientation.

SINGLE Air Locker SYSTEM

Figure 20.

30

6 Mounting & Connecting the Electrical System

6.2.2.2 Dual Air Locker System

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

recommends that the switches and solenoids be wired according to
Figure 21. For safety reasons, this configuration allows SOLENOID
2 to be actuated only if SOLENOID 1 is already on.

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

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

NOTE : Refer to Figure 19. for the correct switch terminal

identification and switch orientation.

 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.

DUAL Air Locker SYSTEM

Figure 21.

31

7 Testing & Final Assembly

7.1 Leak Testing

 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.

 Actuate the Air Locker(s).
 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.

 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.

 Check that leaky fittings have been adequately tightened.
 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:

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

axle stands, a chassis hoist, etc.)

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

Locker switch ‘OFF’.

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

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

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

supply up to its maximum pressure.

32

7 Testing & Final Assembly

 Rotate one wheel by hand.
 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.

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

symbol on the switch cover should light up.

 Rotate the same wheel again.
 Both wheels should rotate together.
 Turn the switch off again.
 Rotate the same wheel.
 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.

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

inserting if it is a threaded type plug).

 Wipe differential housing clean of any oil or grease which may

collect dirt or other abrasive particles.

33

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.

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

and were set with an accurate torque wrench.

 Differential fluid complies with ARB recommendations and has

been filled to the correct level.

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

snagging.

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

well away from danger of accidental engagement.

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

Locker(s) are engaged.

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

understand the ARB Air Locker Operating & Service Manual.

 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:

___________________________
___________________________
___________________________
___________________________

34

8 Parts List

8.1 Exploded Assembly Diagram

Figure 22.

(See itemized parts list overleaf)

35

8 Parts List

8.2 Itemized Parts List

(See exploded diagram Figure 22.)

AIR LOCKER MODEL No. : RD131

ITEM # QTY DESCRIPTION PART #

01 2 SEAL HOUSING O-RING 160207
02 1 SEAL HOUSING ASSEMBLY 081806
03 1 SHIM KIT SHK009
04 1 BONDED SEAL 160702
05 1 CLUTCH GEAR 050806
06 1 SPIDER BLOCK 070201
07 1 LONG CROSS SHAFT 060204
08 1 SIDE GEAR 131311R
09 2 COUNTERSUNK SCREWS 200213
10 3 CROSS SHAFT RETAINING PIN 120601
11 2 TAPERED ROLLER BEARING
12 1 FLANGE CAP ASSEMBLY 027310
13 8 RETURN SPRING 150113
14 1 SPLINED SIDE GEAR 131411R
15 2 SHORT CROSS SHAFT 060403
16 4 PINION GEAR 140701R
17 4 PINION THRUST WASHER 151110
18 2 SIDE GEAR THRUST WASHER 151010
19 1 DIFFERENTIAL CASE 013010

* 1 BULKHEAD FITTING KIT (O-RING TYPE) 170105
* 1 PUSH-IN FITTING (5mm to 1/8” BSPP) 170201
* 1 AIR LINE (5mm DIA X 6m LONG) 170301
* 1 NIPPLE, (1/8” to 1/8” BSPT) 170501
* 1 SOLENOID VALVE (12V) 180103
* 1 SWITCH 180209
* 1 SWITCH COVER (FRONT) 180210
* 10 CABLE TIE 180301
* 1 CABLE TIE (4.8 x 200mm) 180302
* 1 WARNING LABEL 210101
* 1 BUMPER STICKER 210102
* 1 OPERATING & SERVICE MANUAL 210200
* 1 INSTALLATION GUIDE 2102131

* Not illustrated in exploded view.

NOT SUPPLIED

36