ARB Air Locker Installation
for a model RD59 Air Locker to be installed in a Dana 35-C axle
- Raise and support the vehicle.
- Remove the wheels and tires.
- Remove the brake components from the axle.
- Remove the differential housing cover and drain the lubricant.
- When removing the differential housing cover, leave one of the top bolts loosely in place until all of the oil is drained from the housing. This will allow you to control the rate that the oil will flow from the housing.
- Rotate the differential case so that the pinion mate gear shaft lock screw is accessible. Remove the lock screw and the pinion mate gear shaft from the case.
- Force the axle shafts in toward the center of the vehicle. Remove the axle shaft C-clip lock from the axle shaft.
- Remove the axle shafts.
- Use care to prevent damage to the axle shaft bearing, which will remain in the axle shaft tube.
- This is a good time to inspect the roller bearing contact surface on the axle shaft for signs of brinelling, spalling and pitting. If any of these conditions exist, the axle shaft and bearing must be replaced.
- Remove both of the differential bearing caps.
- Note the installation reference letters stamped on the bearing caps and housing machined sealing surface. These must be re-assembled exactly as removed.
- Mount the differential spreader to the differential housing.
- Separate the housing enough to remove the case from the housing. Measure
the distance with a dial indicator.
- Caution: Do not spread housing more than 0.38 mm (0.015") to prevent damage.
- Remove differential carrier (Fig. 1).
- When fitting an ARB Air Locker, a replacement bearing and shim pack supplied with the kit is used on the right hand side, but the original bearing and standard shims are used on the left hand (crown wheel) side.
- Remove old bearings and shims from the differential carrier and identify left and right. Assess condition of bearings and shims and replace as necessary, remembering that only one bearing and shim pack will be re-used. Note that the shims on the crown wheel side may need to be changed to achieve correct backlash.
- Remove the ring gear from the old differential carrier.
- Fit the ring gear to your new ARB Air Locker differential carrier (Fig.
3).
- Note: Heat the ring gear in hot water or in an oven to 175-212 degrees fahrenheit to facilitate assembly, ensuring the mating surfaces are clean before assembly.
- Torque ring gear bolts to vehicle makers specifications using Loctite 290 on threads before tightening.
- Mark the differential housing for a convenient hole location for the brass
bulkhead fitting. While this location is not critical, the hole should be in
the upper part of the differential housing toward the right hand side of the
vehicle.
- This will allow the plastic air line to be run over the top of the axle housing, and provide clearance for the bulkhead fitting and copper tube on the inside of the differential housing from the differential.
- Drill a 7/16" diameter hole and tap a 1/4" NPT thread. Use cloth to protect the pinion gear and pinion bearings from swarf (Fig. 2).
- The differential carrier may now be trial assembled into the differential housing. Re-install the ring gear side as per a standard differential carrier. On the air inlet side the procedure is: bearing inner, bearing outer, O-rings, seal housing, adjusting shims and the 2.5mm spacer washer. Assemble the differential carrier as above and as shown in Figure 5, but do not fit seal O-rings at this stage.
- Set backlash approximately, but do not set bearing preload. Place the differential carrier assembly into the differential housing with the seal housing tube protruding straight out.
- Select the non-ring gear side bearing cap and measure the hole location
for the seal housing tube. Drill the bearing cap with a 1/4" bit for
the seal housing tube (Fig. 6).
- Note: Makes sure backlash is within +/- 0.010" of the correct tolerance to ensure that the seal housing tube hole location is correct.
- Bend the seal housing tube to protrude through the tapped hole for the bulkhead fitting in the differential housing, ensuring that there is ample clearance from the differential carrier and ring gear. Mark the tube at a point flush with the outside of the housing.
- Remove the differential carrier from the differential housing. Remove the seal housing, cut the tube with a tube cutter as marked, deburr and clean.
- Clean all parts of the differential assembly. Assemble the differential
carrier as directed in step #5, now fitting seal housing with O-rings
(Fig. 7).
- Lubricate O-rings with oil prior to assembly (Fig. 4).
- Set the differential carrier preload and backlash in accordance with
vehicle manufacturer's recommendations.
- Note: New shims have been provided in .003", .005", .010", and .030". Original shims are also available in these sizes.
- Install the crown wheel side bearing cap and torque to vehicle manufacturer's specifications.
- Screw the lower compression nut into the bulkhead body. Screw the bulkhead
body into the tapped hole from the OUTSIDE of the housing, feeding
the tubing up through the inside.
- Note: To obtain an oil tight seal, use a thread sealant on the external thread of the bulkhead body.
- Slide the 3/16" (or 1/8") ferrule over the copper coated bundy
tubing. Screw in the central compression nut (making sure that the end with
the thread undercut is down) and torque up, ensuring that the ferrule is
tight on the tube.
- Refer to the Compressor Installation Instructions for the correct procedure for fitting the blue plastic tubing using the remaining bulkhead fitting components.
- Slide the axle shafts into the carrier (Fig. 8). Install the C-clips and withdraw the axle shafts (Fig. 9). Insert the cross shaft retaining pin and screw (Fig. 10).
- Install the second bearing cap and torque up all bearing cap bolts to the vehicle manufacturer's specifications.
- Install the differential cover on the differential housing using a new
gasket and sealant.
- Be sure to clean the old sealant from the differential housing and differential cover mating surfaces prior to re-assembly of the differential cover.
- Take care not to over tighten the screws as this may cause the differential cover to distort.
- Refill axle housing with good quality differential oil, referring to the
vehicle manufacturers' specifications for the oil type and quantity.
- Although the Air Locker does not require any special gear oil, ARB recommends using a limited slip differential oil to maximize the life of all differential components.
- Install brake components to the axle.
- Install wheels and tires.
Steve
Nantz of Moab Off Road removes the open differential carrier from the rear axle
of "Project ZJ".
With
the axle shafts, differential carrier, and ring gear removed, the 7/16"
hole can be drilled for the brass bulkhead fitting. If the pinion gear is not
being upgraded at this time, a cloth should be used to protect the pinion gear
and pinion bearings from swarf when drilling. It's also wise to cover the axle
tubes at the same time.
When
fitting the ring gear to your new ARB Air Locker differential carrier, be sure
not to damage the bolt threads. The use of Loctite 290 on the threads will
ensure a tight fit for years to come.
A
high-quality lubricant such as "Sil-Glyde" should be used on the
O-rings to assure longevity.
When
fitting the ARB Air Locker to your differential housing, the stock shim setup on
the ring gear side of the differential assembly will usually be reused.
Instead
of drilling a 1/4" hole in the bearing cap for the copper seal housing
tube, the experts at Moab Off Road have an alternative method. Here, Steve Nantz
uses a die grinder to cut a notch in the bearing cap. (NOTE: Using the
"notch" technique can jeopardize structural integrity of the bearing
cap if done incorrectly. ARB recommends drilling a 1/4" hole for most
applications.)
With
the seal housing in place, the bearing cap fits easily around the copper seal
housing tube.
With
the ARB Air Locker properly installed, and the preload and backlash set to
manufacturer's recommendations, it's now time to re-insert the axle shafts in
the axle housing.
To
reinstall the rear axle shafts, first lubricate the bearing bores and seal lips
with gear lubricant. Next, insert the axle shafts through the seals and bearings
until they are visible in the "window" located on the ARB Air Locker
differential. Now the C-clips can be installed on the ends of the axle shafts.
Once
the C-clips are installed, withdraw the axle shafts and insert the cross shaft
retaining pin. Align the hole in the shaft with the hole in the ARB Air Locker
differential and install the lock screw.
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