ARB RD102 User Manual

RD102

DANA 35, 27 SPLINE, 3.54 & UP

INSTALLATION GUIDE

Copyright © 2002 by ARB Corporation Limited

Part No. 2102102

Revision Date 21/01/04

No liability is assumed for damages resulting in the use of the information contained herein.
ARB Air Locker Air Operated 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 Central and South American enquiries [e-mail]
Other international enquiries [e-mail]

www.arb.com.au

Table of Contents:

1 Introduction 3

1.1

Pre-Installation Preparation 3

1.2

Tool-Kit Recommendations 4

1.3

2 Removing the Existing Differential 6

3 Installing the Air Locker 12

3.10

3.11

4 Installing the Air System 28

5 Mounting & Connecting the Electrical System 33

6 Testing & Final Assembly 38

Assembly Type Identification 5

2.1

Vehicle Support 6

2.2

Differential Fluid Drain 6

2.3

Removing the Axles 7

2.4

Marking the Bearing Caps 8

2.5

Checking the Current Backlash Amount 9

2.6

Removing the Differential Center 10

3.1

Insuring Adequate Oil Drainage 12

3.2

Installing the Carrier Bearings 14

3.3

Approximate Backlash Shimming 15

3.4

Mounting the Ring Gear 17

3.5

Drilling and Tapping the Bulkhead Port 18

3.6

Assembling the Seal Housing 19

3.7

Pre-Load Shimming 20

3.8

Reinstalling the Bearing Caps 23

3.9

Checking the Backlash 24
Setting Up the Bulkhead Fitting 25
Profiling the Seal Housing Tube 27

4.1

Mounting the Solenoid 28

4.2

Running & Securing the Air Line 30

4.3

Connection to the Bulkhead Fitting 31

5.1

Mounting the Actuator Switch(es) 33

5.2

Wiring the Actuator System 34

6.1

Leak Testing 38

6.2

Reinstalling the Axles 38

6.3

Testing the Air Locker Actuation 41

6.4

Re-Sealing & Filling the Differential 41

6.5

Post-Installation Check List 42

7 Parts List 43

7.1

Exploded Assembly Diagram 43

7.2

Itemized Parts List 44

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 differential housing spreader, to facilitate removal of the carrier.
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 3.3)

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 for pressure fittings

(e.g., LOCTITE #567 Teflon paste)

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.

4

1 Introduction

A

B

‘C’ CLIP

1.3 Assembly Type Identification

IMPORTANT:

Sections 2 and 6 of this installation guide have been written to
accommodate two different Dana 35 applications:

A The ‘C’ clip retained axle shaft (Refer to Fig.1.)
B the non-‘C’ clip type axle shaft (Refer to Fig.2.)

To eliminate confusion, you should identify which figure your axle
matches with. The section numbers within the guide that refer ONLY
to the ‘C’ clip type have been suffixed with an ‘ A ’, and those that refer
ONLY to the non-‘C’ clip type have been suffixed with a ‘ B ’.

PLEASE IGNORE ALL SECTIONS WHICH

DO NOT APPLY TO YOUR APPLICATION

Figure 1.

Figure 2.

5

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

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

your oil, on your drain plug, or in the bottom of the
housing which may indicate a worn bearing or
differential component.

c Clean any loose dirt from around the differential cover flange area,

the filler plug area, and the drain plug (if any) to avoid
contaminating the differential cavity with abrasive particles.

c Position a fluid drain reservoir under the differential.
c If a drain plug exists, remove it and completely drain all differential

oil from the housing.

c If no drain plug exists then the oil can be drained by loosening the

cover bolts and gently prying the cover away at the bottom until oil
runs out.

HINT : If a drain plug does not exist then it would be a good

idea to drill and tap for a tapered oil drain plug to assist
with future oil changes.

c Once drained, remove the differential cover plate.

6

2 Removing the Existing Differential

2.3 Removing the Axles

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 tubes may result in excessive wear and/or failure of your

differential and axle shafts. ARB strongly recommends that you have

your axle assembly inspected for concentricity and straightness before

2.3.1 A Removing ‘C’ Clip Retained Shafts

c Remove both of the rear wheels and brake drums/rotors according

to you vehicle manufacturer’s service manual.

c Rotate the differential carrier using the drive shaft until you have

clear access to the cross shaft retaining pin.

installing your Air Locker.

c Completely remove the retaining pin by unscrewing it.
c Rotate the differential carrier again until you can completely remove

the cross shaft from the differential.

c Tap the axle shafts inward to unseat the ‘C’ clips from their pockets

in the center of the differential side gears.

c Using needle nosed pliers, remove both ‘C’ clips from the

differential.

c Tap the axle shafts outward until the splines are disengaged from

the differential side gears.

c Gently slide the axle shafts out of the axle tubes until they can be

completely removed from the vehicle.

NOTE : The oil seals are delicate and can be easily damaged.

Support the weight of the axle shafts when drawing
them out of their sockets in the housing.

2.3.2 B Removing Non-‘C’ Clip Semi-Floating Shafts

c Remove both of the rear wheels and brake drums/rotors according

to your vehicle manufacturer’s service manual.

c Remove the axle retaining nuts holding the retaining plate to the

axle tube assembly.

NOTE : The axle retaining nuts and bolts are not

recommended for re-use and should be re-placed at
the time of reassembly.

7

2 Removing the Existing Differential

c Pull the axle free of the axle bearing using a slide hammer.
c Gently slide the axle shafts out of the axle tubes until they can be

completely removed from the vehicle.

NOTE : The oil seals are delicate and can be easily damaged.

Support the weight of the axle shafts when drawing

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.3.)

HINT : Many installers choose to make one punch mark on

them out of their sockets in the housing.

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 3.

8

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 authorized

ARB installer for more information.

c Set a depth indicator on one of the ring gear teeth as in figure 4.

Figure 4.

c While supporting the pinion gear by holding the drive shaft 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.

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

9

2 Removing the Existing Differential

2.6 Removing the Differential Center

IMPORTANT:

YOU MUST SPREAD THE HOUSING ON DANA 35 MODELS

Spreading the differential housing with a differential case

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

cast iron Dana 35 differential housings. Improper pre-load will

result in undue bearing wear, increased stresses in the

differential center, increased running noise, and ultimately, ring

and pinion gear damage.

c Remove both bearing caps.
c Carefully spread the housing (Fig.5.) enough to remove the

differential center. (Refer to your vehicle’s service manual).

NOTE : Do not spread the housing more than 0.50mm [0.020”].
NOTE : Be sure not to mix up the left and right hand bearing

cups and master shims. Later it will be necessary to
know which cup and shim came from which side.

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

be removed by pulling forward on the differential carrier.

Figure 5.

NOTE : The differential center is heavy and quite difficult to

handle when covered in oil. Take care not to drop it.

c Relieve any tension on the spreader immediately after the

differential has been removed.

10

3 Installing the Air Locker

3.1 Insuring Adequate Oil Drainage

IMPORTANT:

Some axles were manufactured with poor oil drainage between

the axle tubes and the differential housing. This can often result

in one of the axle tubes filling up with differential oil while

running. In most cases this will result in a blocked air vent which

will cause the differential housing to pressurize and expel oil

from the axle seals at the wheels or force oil into the air system

of the Air Locker, eventually expelling oil at the solenoid valve.

This is a design flaw which was corrected by most automakers in

the later releases of their axle assemblies. If no lower drainage

points are present in the differential housing then it is critical

that you modify the housing to include them.

c Inspect the differential housing for the presence of adequate

drainage in both axle tubes (refer to Fig.6.).

Figure 6.

c If no drainage exists then two slots should be created in the bearing

seat face of both axle tubes; one on the upper side of the tube, and
one on the lower side. Figure 7. shows an example of an axle
housing with no existing oil drainage.

11

3 Installing the Air Locker

Figure 7.

Figure 8.

NOTE : Cover the differential housing cavity and the axle tube

openings with a rag to protect them from metal filings.

12

3 Installing the Air Locker

c If no drainage slot is present at the upper left-hand side (refer to

Fig.6.) of the housing at all, then a slot (not a hole) will have to be
created here as clearance for the seal housing tube
(Refer to Section 3.8 Reinstalling the Bearing Caps).

c If drainage exists but is inadequate then slots or holes should be

cut into the housing on the upper and lower side of the tubes where
required.

NOTE : Figure 9. shows upper and lower drainage slots cut

into a bearing seat which had no existing drainage at
all before modification.

Figure 9.

c Remove any sharp edges left behind by the modifications that

could break off and fall into the cavity.

c Make sure any grinding dust, filings or drill chips left behind by

cutting the drainage slots are completely cleaned out of the
housing.

c Check that the axle air vents are clear and working correctly.

13

3 Installing the Air Locker

3.2 Installing the Carrier Bearings

c Apply a thin film of high pressure grease to both bearing journals of

the Air Locker to prevent seizing.

c Using a bearing press or arbor press, press one of the bearing

cones (supplied with the Air Locker kit) onto one bearing journal of
the Air Locker (refer to Figure 10.) until the bearing seats firmly
against the bearing journal shoulder.

Figure 10.

c Invert the Air Locker and press the other tapered roller bearing

cone onto the opposite bearing journal of the differential carrier until
the bearing seats firmly against the bearing journal shoulder.

NOTE : Do not add any shims between the bearings and the

bearing seat. Shimming of the Air Locker will be
performed with the supplied shim kits and/or the
original master shims (if any) on the outside of the
carrier bearings.

14

3 Installing the Air Locker

3.3 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.

c Secure the original differential to a work bench.
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.

Figure 11.

c Assemble the original bearing cup onto the cone of the right-hand

side of the original differential carrier.

c 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 outer face of the
bearing cup to the ring gear mounting face (shown as ‘A’ in Figure

11.) and record this measurement as ‘A’.

NOTE : Be sure to measure using the bearing cup that

originally came off of the right-hand side.

15

3 Installing the Air Locker

c Assemble the new bearing cup and master shim (supplied with your

Air Locker kit) onto the right-hand side of the Air Locker (as shown
in Fig.12.) and measure the total distance ‘B’.

NOTE : The shim pack ‘C’ should not be installed at this time.

Figure 12.

c Record this measurement as ‘B’.
The thickness of the shim pack ‘C’ should make the distance ‘B’ on the

Air Locker closely match the distances ‘A’ on the original differential
(within 0.1mm [0.004”] ).

c Use the following calculation to find the desired thickness of ‘C’:

A – B = C (Replacement Shim Pack)

HINT : If your calculations are correct then the following

equation will also be true:

A – B – C = ZERO

16

3 Installing the Air Locker

c Select shims from the shim kit supplied with your Air Locker to

make the thickness ‘C’ as determined above.

c Place this shim pack between the master shim and the bearing cup.
c Re-measure the new distance ‘B’ from the Air Locker (now

including the shim pack ‘C’) to make sure that it matches the
distance ‘A’ on the original differential.

NOTE : NEVER machine the Air Locker.

3.4 Mounting the Ring Gear

IMPORTANT:

Newer OEM Dana 35 ring and pinion sets use 7/16” bolts.

The flange holes of the Air Locker must be reamed from

Ø3/8” to Ø7/16” to suit.

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

of the Air Locker to prevent seizing.

c 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 between the ring gear and the Air
Locker flange.

HINT : Stoning the ring gear mounting face before

installation will remove any high spots around the
threads.

c Heat the ring gear to between 80 and 100°C [175 - 212°F] in hot

water or in an oven 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 gear and bolt holes with compressed air (if wet).
c Install the ring gear onto the Air Locker by aligning the bolt holes

and then gently tapping it around in a circle with a soft mallet.
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. 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.

17

3 Installing the Air Locker

3.5 Drilling and Tapping the Bulkhead Port

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

NOTE : Higher ratio gearing uses deeper (thicker) ring gears

with teeth that extend much further. Make sure the
intended hole location is far enough away from the
ring gear teeth that the air line will not be at risk of
contact with the current or future ring gears.

c Mark a spot on the top of the outside shell of the differential

housing approximately 30mm [1.25”] in as shown in Figure 13.

Figure 13.

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 a

11.2mm [7/16”] drill.

c Tap the hole from the outside using a ¼” NPT pipe tap.
c Remove any sharp edges from the hole that may chip-off and fall

into the housing.

c Carefully remove the rags and inspect with a service light inside the

housing to insure no metal filings are left behind.

18

3 Installing the Air Locker

3.6 Assembling the Seal Housing

Figure 14.

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

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

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

other conditions which might cause leaks.

c 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.

c 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.

c Assemble one of the two master shims (included with the Air

Locker shim kit) onto the stepped face of the seal housing with the

rounded edge of the shim facing out.

NOTE : No shims other than the single master shim should be

assembled onto the seal housing at this time.

c Carefully install the seal housing (master shim towards the

center) by sliding it all of the way onto the bearing journal with a

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

19

3 Installing the Air Locker

3.7 Pre-Load Shimming

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 ‘D’ in Figure 14.

c Insert and hold the Air Locker into the differential housing.

IMPORTANT:

Some Dana 35 pinion gears extend so far into the differential

cavity that they make contact with the body of the Air Locker.

If this is the case then the end of the pinion gear will have to

be carefully ground or machined away until at least 0.5mm

[0.020”] of clearance exists. This will not adversely effect the

strength of the pinion gear.

Clean all grinding particles from the pinion gear & differential

housing after modifications.

NEVER MODIFY THE AIR LOCKER TO CREATE CLEARANCE.

c Insert the remaining master shim from the Air Locker shim kit

between the right-hand bearing cup and the bearing seat of the
axle housing with the rounded edge of the master shim facing away
from the center.

c Insert the shim pack determined earlier as ‘C’ between the bearing

cup (right-hand side) and the master shim.

c Insert the original master shim from the right-hand side of the

original differential back into the housing between the Air Locker
master shim and the bearing seat of the axle housing.

c Push (or lightly pry) the Air Locker hard across to the right-hand

side, and measure the maximum gap (also called the ‘end float’)
between the outside of the seal housing and the inside face of the
axle housing with an automotive feeler gauge. (Fig.15.)

20

3 Installing the Air Locker

Figure 15.

c Consult your vehicle manufacturer’s service manual to determine

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

PRE-LOAD + END FLOAT = SHIM PACK

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

the feeler gauge to determine a shim amount for ‘D’ in Figure 14.

c Create a shim pack ‘D’ from the shims supplied with your Air

Locker.

NOTE : Do not add shims between the bearing cone and the

c Remove the Air Locker from the axle housing.
c Install the shim pack ‘D’ between the master shim and the seal

housing as shown in Figure 14.

c Spread the differential housing again (Refer to Section 2.6).
c Re-install the Air Locker assembly into the axle housing without the

original master shim from the right-hand side.

c Rotate the seal housing until the tube is positioned in the center of

the oil drainage notch of the axle housing.

bearing seat and NEVER machine the Air Locker.

c While holding the Air Locker into the axle housing, lightly tap the

original right-hand master shim into place on the right-hand side
between the Air Locker master shim and the bearing seat of the
axle assembly. (Refer to Figure 16.)

21

3 Installing the Air Locker

Figure 16.

NOTE : If the master shim is too tight to fully install then the

spreader tension may need to be increased. Do not
spread the housing more than 0.50mm [0.020”].

c Release all spreader tension.
c Check that some backlash can be felt between the ring and pinion

gears. No backlash would be an early indication of incorrect shim
thickness.

22

3 Installing the Air Locker

3.8 Reinstalling the Bearing Caps

IMPORTANT:

The Air Locker master shim must be assembled between the

stepped side of the seal housing and the bearing cup.

NOT HAVING THE MASTER SHIM IN PLACE

HERE WILL CAUSE BEARING FAILURE.

c Using a soft instrument such as a piece of wood, bend the seal

housing tube outward and away from the position of the bearing
cap and into the drainage groove area. (Fig.17.)

Figure 17.

NOTE : The seal housing tube should lay as low in the seal

housing groove as possible.

c Install the bearing caps oriented as they were marked before they

were removed, and tighten the bearing cap bolts. It is not
necessary to torque them down at this time.

c Check that some clearance exists between the bearing cap and the

seal housing tube. If not, the bearing cap should be removed and
the tube re-bent for adequate clearance.

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

specified in your vehicle manufacturer’s service manual.

23

3 Installing the Air Locker

3.9 Checking the Backlash

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

Figure 18.

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 18.

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.

24

3 Installing the Air Locker

3.9.1 Re-Shimming the Backlash

NOTE : This step is only necessary when adjusting for

incorrect backlash.

c Remove the bearing caps.
c Remove the differential as before.
c To decrease the amount of backlash, reduce the shim thickness ‘C’

(Fig.12.) and increase the shim thickness ‘D’ (Fig.14.) by the same
amount. Reverse this step to increase the backlash.

c Remount the differential as before.
c Release spreader tension (if applicable).
c Check backlash again as before.

3.10 Setting Up the Bulkhead Fitting

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 Insert the free end of the seal housing tube into the bulkhead fitting

until it protrudes approximately 8mm [5/16”] through the other side.

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

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

c While still 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.19.), 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.19.)

25

3 Installing the Air Locker

Figure 19.

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.

26

3 Installing the Air Locker

3.11 Profiling the Seal Housing Tube

c Completely remove the differential spreader.
c Without using sharp, jagged tools such as pliers (usually your

hands are the best tool for this job), gently bend the seal housing
tube so that it runs along the inside of the differential housing as
shown in Figure 20.

Figure 20.

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.

27

4 Installing the Air System

4.1 Mounting the Solenoid

4.1.1 Connection to an ARB Air Compressor (Fig.21.)

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 21.

28

4 Installing the Air System

4.1.2 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 reengage 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.

29

4 Installing the Air System

4.2 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.
(Not necessary on IFS installations)

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
your line from getting snagged.

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.

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 which 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, always trim the line to length with

a sharp knife to avoid distorting the tube where it plugs into the
push-in fitting.

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.

30

4 Installing the Air System

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.

4.3 Connection to the Bulkhead Fitting

c In the case of an IFS axle assembly or in the case that the axle

assembly has been completely removed from the vehicle, the
assembly will have to be remounted in order to position the
bulkhead fitting in its correct location for air line access.

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.22.)

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 22.

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

31

4 Installing the Air System

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
the tubing.

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

32

5 Mounting & Connecting the Electrical System

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

33

5 Mounting & Connecting the Electrical System

Figure 23.

5.2 Wiring the Actuator System

5.2.1 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. 24.)

NOTE : Refer to your ARB Air Compressor Installation Guide

for details on configuring your installation.

34

5 Mounting & Connecting the Electrical System

IDENTIFICATION

ARB AIR COMPRESSOR WIRING LOOM

Figure 24.

SWITCH

TERMINAL

Figure 25.

UP

35

5 Mounting & Connecting the Electrical System

5.2.2 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 26. and 27., depending
on whether one or two Air Lockers will be installed in the vehicle.

5.2.2.1 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 26. 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 25. for the correct switch terminal

identification and switch orientation.

SINGLE Air Locker SYSTEM

Figure 26.

36

5 Mounting & Connecting the Electrical System

DUAL

SYSTEM

5.2.2.2 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 27. 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 25. 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 27.

37

6 Testing & Final Assembly

6.1 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

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

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.

compressor tank O-ring seal.

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

persists.

6.2 Reinstalling the Axles

c Unscrew and remove the long cross shaft retaining pin using a

5mm hex key.

NOTE : The long cross shaft retaining pin is the pin located

exactly one quarter turn of the differential from the ‘C’
clip access window. Rotate the differential using the
drive flange.

38

6 Testing & Final Assembly

Figure 28.

6.2.1 A Reinstalling ‘C’ Clip Retained Shafts

c Remove the long cross shaft.

Figure 29.

c Rotate the differential until the ‘C’ clip access window is in full view.
c Insert both axles fully into the housing and gently tap them inward

as far as they will go.

NOTE : To prevent damage to the oil seals, support the weight

of the axle shaft when inserting them.

c Using needle nosed pliers, insert one of the ‘C’ clips onto the

groove in the axle shaft by sliding it between the spider block and a
side gear. (Refer to Figure 30.)

NOTE : You may have to slide the axle shaft outward very

slightly to adequately line up the groove.

39

6 Testing & Final Assembly

c Pull outward on the axle shaft to seat the ‘C’ clip into the side gear.
c Repeat the ‘C’ clip installation steps on the second axle shaft.
c Re-insert the long cross shaft.
c Using an automotive feeler gauge, check the maximum distance

between the axle shaft and the cross shaft. This measurement is
what is known as the end float.

c Refer to your vehicle manufacturer’s service manual for the

appropriate end float amount. ‘C’ clips may need to be substituted
with others of a different thickness to achieve correct end float if too
tight or too loose.

c Insert and tighten the retaining pin with a 5mm hex key.
c Reconnect the drive shaft to the differential drive flange.
c Reassemble the remainder of the differential assembly

(e.g., hubs, brakes, wheels, etc.) to the vehicle according to your
vehicle’s service manual.

Figure 30.

6.2.2 B Reinstalling Non-‘C’ Clip Retained Shafts

c Insert and tighten the retaining pin with a 5mm hex key.
c Reconnect the drive shaft to the differential drive flange.
c Reassemble the remainder of the differential assembly

(e.g., hubs, brakes, wheels, etc.) to the vehicle according to your
vehicle’s service manual.

40

6 Testing & Final Assembly

6.3 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’.

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 While supporting the drive shaft flange, 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.

6.4 Re-Sealing & Filling the Differential

NOTE : Consult the ARB Air Locker Operating & Service

Manual for recommendations on differential lubricant
specifications.

c Replace the differential cover using gasket sealant or a new

standard differential cover gasket for your make of vehicle.

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 which may

collect dirt or other abrasive particles.

41

6 Testing & Final Assembly

6.5 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:

___________________________
___________________________
___________________________
___________________________

42

7 Parts List

7.1 Exploded Assembly Diagram (See itemized parts list overleaf)

Figure 31.

43

7 Parts List

7.2 Itemized Parts List

(See exploded diagram figure 31.)

AIR LOCKER MODEL No. : RD102

ITEM # QTY

01 1 SPLINED SIDE GEAR 131601H
02 1 SPIDER BLOCK 070801
03 1 LONG CROSS SHAFT 061302
04 1 SIDE GEAR 131501H
05 2 SIDE GEAR THRUST WASHER 151011
06 2 COUNTERSUNK SCREW 200213
07 2 CROSS SHAFT RETAINING PIN 120601
08 2 SEAL HOUSING O-RING 160235
09 1 SEAL HOUSING ASSEMBLY 081801
10 2 SHIM KIT SHK003
11 2 TAPERED ROLLER BEARING 160109
12 1 FLANGE CAP ASSEMBLY 028504
13 1 BONDED SEAL 160701
14 1 CLUTCH GEAR 050803
15 8 RETURN SPRING 150107
16 1 SHORT CROSS SHAFT 061402
17 3 PINION GEAR 140801H
18 3 PINION THRUST WASHER 151112
19 1 DIFFERENTIAL CASE 013104

* 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 (REAR) 180211
* 10 CABLE TIE 180301
* 1 WARNING LABEL 210101
* 1 BUMPER STICKER 210102
* 1 OPERATION & SERVICE MANUAL 210200

* 1 INSTALLATION GUIDE 2102102

* Not illustrated in exploded view.

DESCRIPTION PART #

44