ARB RD106 User Manual

RD106

NISSA

N C200, 31 SPLINE

INSTALLATION GUIDE

Part No. 2102106

Revision Date 19/01/05

Copyright © 2003 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 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

2 Removing the Existing Differential 5

3 Bench Measurement 10

4 Installing the Air Locker 13

4.10

4.11

4.12

5 Installing the Air System 31

6 Mounting & Connecting the Electrical System 36

7 Testing & Final Assembly 41

8 Parts List 45

Tool-Kit Recommendations 4

2.1

Vehicle Support 5

2.2

Differential Fluid Drain 5

2.3

Removing the Axles 5

2.4

Marking the Bearing Caps 6

2.5

Checking the Current Backlash Amount 7

2.6

Spreading the Differential Housing 8

2.7

Use of the Thrust Block 9

3.1

Measurement for Pre-Load Shimming 10

3.2

Calculation & Selection of Shims 12

4.1

Insuring Adequate Oil Drainage 13

4.2

Installing the Carrier Bearings 16

4.3

Mounting the Ring Gear 17

4.4

Drilling & Tapping the Bulkhead Port 18

4.5

Assembling the Differential Carrier 19

4.6

Approximating the Backlash for Tube Position 20

4.7

Modifying the Bearing Cap 22

4.8

Air Locker Final Assembly 26

4.9

Final Backlash Checking 26
Profiling the Seal Housing Tube 28
Setting Up the Inner Bulkhead Fitting 29
Reinstalling the Axles 30

5.1

Mounting the Solenoid 31

5.2

Running & Securing the Air Line 33

5.3

Connection to the Bulkhead Fitting 34

6.1

Mounting the Actuator Switch(es) 36

6.2

Wiring the Actuator System 37

7.1

Leak Testing 41

7.2

Testing the Air Locker Actuation 41

7.3

Re-Sealing & Filling the Differential 42

7.4

Post-Installation Check List 43

8.1

Exploded Assembly Diagram 45

8.2

Itemized Parts List 46

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 Automotive brake tubing cutters to cut the steel tubing.
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 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 cover plate seal to prevent dirt from

entering the differential.

c Position a fluid drain reservoir under the differential.
c Remove the differential drain plug and completely drain all

differential fluid.

c Once drained, reinstall the drain plug finger tight to prevent drips

coming out of the housing and dust getting in.

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 Removing the Axles

c Remove the axles as indicated in your vehicle manufacturer’s

service manual. In the case of IFS differential assemblies this will
require the removal of the entire assembly first.

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

installing your Air Locker.

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 authorized

ARB installer for more information.

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

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.

7

2 Removing the Existing Differential

2.6 Spreading the Differential Housing

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 center,

increased running noise, and ultimately, ring and pinion gear

damage.

c Unbolt and remove the bearing caps from the differential housing.

HINT : Be sure not to mix up the left and right hand bearing

caps. Later it will be necessary to know which cup
came from which bearing and which shim came from

c Carefully spread the housing (Fig.3.) enough to remove the

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

which side.

NOTE : Do not spread the housing more than 0.50mm

[0.020”].

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

be removed by pulling forward on the differential carrier.

Figure 3.

NOTE : Keep the shims separated so that they can be

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

c Release all spreader tension immediately after removing the

differential carrier.

8

2 Removing the Existing Differential

2.7 Use of the Thrust Block

IMPORTANT:

This model of Air Locker was manufactured to replace

Nissan differentials which employ either of the two distinctly

different methods of retaining the axle shafts.
1 Full Floating Axles
2 Semi-Floating Axles

Depending on which axle type you have, you may be required

to install the thrust block included with the Air Locker

kit before final assembly.

4.3.1 Full Floating Axles

Full-floating axles are completely supported and therefore do not
require a thrust block at all.

4.3.2 Semi-Floating Axles

Semi-floating axles are only retained inward at the wheel end of the
axle shaft and are supported in the center of the axle assembly by a
thrust block. You can easily identify this by looking through the axle
splines of your original differential carrier to see if a thrust block was
used.

If this is the case then you will have to insert the thrust block (supplied
with the Air Locker kit) into the differential center just before inserting
the Air Locker into the axle housing.

HINT : A wad of thick grease on the thrust block should keep

it from sliding around during installation.

9

3 Bench Measurement

3.1 Measurement for Pre-Load Shimming

When fitting an ARB Air Locker, a variable shim pack (supplied) is
used in conjunction with the original bearing on the right hand side of
the differential (as pictured in Fig.12.) in order to achieve the correct
ring and pinion backlash and carrier bearing pre-load once the Air
Locker has been installed. Because of this, the original shim from this
side will not be reused.

The original bearing type and shim type are used on the left hand (ring
gear) side of the Air Locker (as pictured in Fig.5.). Measurements will,
however, need to be taken to determine the correct shim thickness for
this side in order to reproduce a similar backlash and pre-load to that
of your existing differential.

The large spacer on the outside of the ring gear side shim must be
retained and re-fitted when the Air Locker is installed.

NOTE : Keep the shims separated so that they can be

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

c Secure the 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.

c Remove the original bearings from the differential center using a

bearing puller.

c Using a caliper or similarly accurate measurement method

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

c Measure the thickness of the shim (not the spacer) 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’.

10

3 Bench Measurement

Figure 4.

Figure 5.

11

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:

§ Either machine the ring gear side shim, or purchase a new one
of the correct thickness from your Nissan dealer.

§ Add shims between the master shim and the seal housing.

§ Use a universal shim kit available from most drive train

specialists.

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

12

4 Installing the Air Locker

4.1 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.

13

4 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.

14

4 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.

15

4 Installing the Air Locker

4.2 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 onto the bearing
journal.

c Press the 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 which are damaged or

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

to the seal housing side bearing journal.

c Press the second bearing cone onto the opposite bearing journal,

taking care not to damage the O-ring grooves. (Figure 10.)

worn.

Figure 10.

NOTE : Do not add any shims between the seal housing

bearing and the bearing seat.

16

4 Installing the Air Locker

4.3 Mounting the Ring Gear

IMPORTANT:

Your Air Locker was manufactured to replace differentials using

12mm [0.472”] diameter ring gear bolts. Ring gears with smaller

bolts should ONLY be installed using cylindrical spacers to

reduce the clearance between the bolts and the Air Locker flange.

(not supplied)

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 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.

c 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.

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.

17

4 Installing the Air Locker

4.4 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 right 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.

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

them from metal filings.

Figure 11.

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

11.2mm [7/16”] drill. (Fig.11.)

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 insure no metal filings are left behind.

18

4 Installing the Air Locker

4.5 Assembling the Differential Carrier

c Relieve all tension on the housing spreader.
c Place the bearing cup over the bearing cone (Figure 12.).

Figure 12.

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.

c Install the supplied master shim onto the seal housing.

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

required thickness (shown as ‘E’ in Figure 12.) has yet
to be determined.

19

4 Installing the Air Locker

c Hold the bearing cup in place on the ring gear side.
c Holding the master shim and tapered roller bearing cup 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 or slotted as clearance
for the seal housing tube.

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 master shim and the housing 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 12.

PRE-LOAD + END FLOAT = SHIM PACK

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

pack of this thickness.

c Remove the Air Locker and assemble the shim pack onto the seal

housing spigot behind the master shim (Figure 12.).

c Spread the differential housing again (Refer to section 2.6).

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

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

0.50mm [0.020”].

c Reinstall the Air Locker as before (i.e., with only one bearing cap).
c Release all spreader tension.

4.6 Approximating the Backlash for Tube Position

If the backlash is not close enough to the specified amount, the tube
position cannot be accurately measured to modify the bearing cap for
tube clearance. This must be checked before hand.

20

4 Installing the Air Locker

c Set a depth indicator on one of the ring gear teeth as in figure 13.
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).

c Make sure backlash is less than 0.5mm.

NOTE : This backlash value is for the tube position only and

will not be used for final assembly.

Figure 13.

4.6.1 Re-Shimming the Backlash

NOTE : This step is only necessary when adjusting for

incorrect backlash.

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

(Fig.4.) and increase the shim thickness ‘E’ (Fig.12.) by the same
amount. Reverse this step to decrease the backlash.

c Remount the differential as before.
c Release spreader tension.
c Re-check backlash.

21

4 Installing the Air Locker

4.7 Modifying the Bearing Cap

A clearance for the seal housing tube must be made in the
bearing cap.

4.7.1 Marking the Tube Position

With the Air Locker in place and less than 0.5mm of backlash, an
accurate measurement for the seal housing tube clearance can be
made.

NOTE : Take time and double check when taking your

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

c With the seal housing tube pointing straight out, measure the

distance from a fixed position inside the differential housing to the
center of the seal housing tube. (Fig.14.)

Figure 14.

c Record your findings and recheck for accuracy.
c Remove the bearing cap from the ring gear side of the differential.
c Remove the Air Locker from the differential housing.
c Install the seal housing side bearing cap and hand-tighten the

bearing cap bolts.

22

4 Installing the Air Locker

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 Measure to the bearing cap from exactly the same position on the

differential housing that you took the previous measurements from.
(Fig.15.)

c Mark the tube position where the clearance is to be made for the

seal housing tube with a center punch.

Figure 15.

c Remove the bearing cap from the differential housing.
c Measure the distance from the center punch mark made on the

bearing cap to the closest edge of the bearing cap.

c If the center punch mark is greater than 5mm [3/16’’] from the

closest edge of the bearing cap, it is recommended that a small
hole be drilled through the bearing cap (Section 4.7.2). If less than
5mm [3/16’’] from the edge it is recommended that a notch is filed
into the side of the bearing cap to avoid break-through while drilling
(Section 4.7.3).

23

4 Installing the Air Locker

4.7.2 Drilling the Bearing Cap

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

NOTE : Do not apply too much clamping pressure with the

vise. The bearing cap may be damaged.

c Using a pedestal drill, drill a 5mm [3/16’’] hole through the bearing

cap where the seal housing tube hole has been marked.
(Fig.16.)

Figure 16.

c Remove the bearing cap from the vise, turn it upside down, and

re-clamp it in the vise.

c The drilled hole must be chamfered approximately 3mm [1/8”] to

remove any sharp edges that may chip-off and fall into the housing.
(Fig.17.)

24

4 Installing the Air Locker

Figure 17.

4.7.3 Notching the Bearing Cap

c Use a soft jawed vise clamp to hold the bearing cap steady.
c Using a 6.35mm [¼’’] rat-tailed file. File out a notch in the bearing

cap from the closest edge until an adequate notch has been cut
around the position of the punch mark. (Fig.18.).

Figure 18.

c File a chamfer around the inside edge of the notch to remove any

sharp edges from the notch that may chip-off and fall into the
housing.

25

4 Installing the Air Locker

4.8 Air Locker Final Assembly

c Remove the seal housing, shim pack, and master shim, and 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 and master shim.
c Point the seal housing tube straight out of the housing, hold the

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

the tube without fouling.

NOTE : Do not forget to check for the marks on the bearing

caps to insure they are turned the correct way around.

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

4.9 Final Backlash Checking

c Relieve all tension on the housing spreader.
c Tighten all bearing cap bolts with a torque wrench to the torque

specified in your vehicle manufacturer’s service manual.

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

Figure 19.

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.

26

4 Installing the Air Locker

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

Figure 19.

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.

4.9.1 Re-Shimming the Backlash

NOTE : This step is only necessary when adjusting for

incorrect backlash.

c Reapply the spreader to the differential housing.
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.12.) by the same
amount. Reverse this step to decrease the backlash.

c Remount the differential as before.
c Release spreader tension.
c Check backlash again as before.

27

4 Installing the Air Locker

4.10 Profiling the Seal Housing Tube

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.20.)

Figure 20.

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

gear, differential, or the cover plate.

28

4 Installing the Air Locker

4.11 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.21.), 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.21.)

Figure 21.

29

4 Installing the Air Locker

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.

4.12 Reinstalling the Axles

Reinstall the axles and brake assembly according to the guidelines set
forth in your vehicle manufacturers service manual.

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

spline of the axle when inserting them.

NOTE : If you have semi-floating axle shafts then carefully

check the axle end float to make sure you have
correctly installed the thrust block.

30

5 Installing the Air System

5.1 Mounting the Solenoid

5.1.1 Connection to an ARB Air Compressor (Fig.22.)

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 22.

31

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 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.

32

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
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, 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.

33

5 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.

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.23.)

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 23.

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

34

5 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.

35

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

36

6 Mounting & Connecting the Electrical System

Figure 24.

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. 25.)

NOTE : Refer to your ARB Air Compressor Installation Guide

for details on configuring your installation.

37

6 Mounting & Connecting the Electrical System

IDENTIFICATION

ARB AIR COMPRESSOR WIRING LOOM

Figure 25.

SWITCH

TERMINAL

Figure 26.

UP

38

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 27. and 28., 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 27. 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 26. for the correct switch terminal

identification and switch orientation.

SINGLE Air Locker SYSTEM

Figure 27.

39

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 28. 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 26. 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 28.

40

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’.

41

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 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.

42

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) have been 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:

___________________________
___________________________
___________________________
___________________________

43

7 Testing & Final Assembly

44

8 Parts List

8.1 Exploded Assembly Diagram

(See itemized parts list overleaf)

Figure 29.

45

8 Parts List

8.2 Itemized Parts List

(See exploded diagram figure 29.)

AIR LOCKER MODEL No. : RD106

ITEM # QTY

DESCRIPTION PART #

01 1 FLANGE CAP 020103
02 1 CLUTCH GEAR 050102
03 1 DIFFERENTIAL CASE 010105
04 4 PISTON SPRING 150101
05 2 CROSS SHAFT RETAINING PIN 120102

* 2 CROSS SHAFT RETAINING PIN 120302
06 4 SHORT CROSS SHAFT 060308
07 2 SIDE GEAR THRUST WASHER 151003
08 1 PISTON (Polyamide) 040103
09 1 BONDED SEAL 160701
10 1 CYLINDER CAP 030133
11 2 SEAL HOUSING O-RING 160208
12 6 CYLINDER CAP RETAINING BOLT 200205
13 6 TAB WASHER – 8mm 150401
14 - TAPERED ROLLER BEARING

NOT SUPPLIED

15 1 SEAL HOUSING 080802
16 1 SHIM KIT SHK004
17 1 SPLINED SIDE GEAR 130312H
18 4 PINION THRUST WASHER 151101
19 4 PINION GEAR 140101
20 1 SPIDER BLOCK 070101
21 1 THRUST BLOCK 110501
22 1 SIDE GEAR 130112H

* 1 BULKHEAD FITTING (O-RING TYPE) 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

* 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 2102106

* Not illustrated in exploded view.

46