Price and Compare Vehicles: It has been said that differential lockers are only for the hard-core off-road applications, but this is certainly not true. Any four-wheel drive becomes a joy to drive when fitted with ARB lockers, allowing you to tackle off road situations with confidence, at a much slower and safer pace. Unfortunately, conventional (open) differentials are usually fitted as standard equipment on most vehicles. On paved roads this system is very successful, giving predictable handling, even tire wear and requiring very little maintenance. However, in off road situations where traction surfaces vary greatly, this type of differential has a major limitation. When one wheel has greater traction than the other, all the power will be directed to the wheel with the least traction. For example, if one wheel is in the air and the other wheel is still on a hard surface, then all the power will be transferred to the wheel in the air. No power will go to the one on the ground and the vehicle will not move. In a 4x4, the two wheels that receive power are the ones with the least amount of traction. This means that your 4X4 will only be driving on two wheels when traction is needed most. To fully understand how the four-wheel drive system works, one must look at the axle’s differential. The differential lies in the vehicle’s axle housing and is designed to proportion the engines power to the axle shafts, which in turn drive the wheels. For a vehicle to turn, the outside wheels on each axle must turn at a faster rate than the inside wheels. The open differential allows the wheels to turn at different speeds, or independently of each other. This characteristic is desirable on pavement, but when you encounter a surface such as mud or snow, you may find yourself stuck, with only two wheels of your 4x4 spinning uselessly, trying to gain traction.
This is where the ARB Air Locker comes into play. The Air Locker is designed to replace the open differential in your axle housing with a much stronger locking differential that will allow the driver to lock the axle shafts together when needed. When activated, the Air Locker will evenly distribute power to both wheels on the ARB-equipped axle, thus providing 100% traction instantly! Since the ARB Air Locker is driver-controlled, it can be engaged or disengaged at the driver’s discretion. Unlike automatic locking differentials, the ARB Air Locker does not have any adverse effects on the vehicle’s handling characteristics when driving on pavement. This is the case with the Detroit Locker in the rear axle of our Blazer. After going around a corner, the Detroit will give a loud "bang" when the locker engages. Automatic locking differentials force the wheels on the locker-equipped axle to turn at the same speed even when driving on high-traction surfaces. Since the wheels on an axle need to turn independently of each other when driving around a corner, some undesirable characteristics are common with automatic locking differentials:
The ARB Air Locker is controlled pneumatically from the driver’s seat of the vehicle. Once the dash mounted button is pushed, compressed air actuates a piston inside the ARB differential which engages a locking gear, instantly locking the differential and sending power to both wheels…all within one tenth of a second! Another push of the dash mounted button bleeds the air through the solenoid valve allowing small heavy duty coil springs in the ARB differential to release the locking ring. With the ARB differential disengaged, the axle shafts are unlocked and the wheels are once again allowed to turn independently of each other. Compressed air is supplied by an ARB air compressor which can be mounted in any convenient location underneath the hood of the vehicle. The 12-volt compressor features a die-cast aluminum tank, oil-less operation, and a carbon-impregnated piston ring, making the unit virtually maintenance free. Supplied with the ARB air compressor is a wiring harness that makes installation a snap. A relay and pressure switch, air lines and fittings, industrial grade control switches, and all the necessary mounting hardware are also included with the compressor. Features of the ARB air compressor include:
ARB offers a tire inflation kit (Part # PUKT) to integrate directly into the ARB air compressor system. Included with the kit is an air hose with a quick-disconnect air chuck, and all the necessary hardware required to install the kit to your ARB air compressor. When equipped with the tire inflation kit, the ARB air compressor is capable of inflating a 33x12.50 tire from 15-32 p.s.i. in 4.5 minutes. Installation: Begin by draining the differential and removing the axle shafts. For the front axle, this requires removing the calipers, hubs, disk brakes and spindle. The differential cover is also removed.
After removing the shafts, the old carrier can be removed. The inside of the housing is then cleaned with brake cleaner. After cleaning the carrier, carefully mark, drill, and tap a hole for the air line bulkhead fitting. It's best to perform this step before installing the differential and before any bearings are in the carrier. While this location is not critical, the hole should be in the upper part of the differential housing toward the drivers side of the vehicle. This will connect the plastic air line to the top of the axle housing, and provide clearance for the bulkhead fitting and copper tube on the inside of the differential housing. A 7/16" bit and a 1/4" NPT tap is used for this. Be sure to remove any metal particles after this operation so you don't damage the Air Locker, gears or bearings. This is also a good time to remove the old differential gasket. We prefer a small wire wheel mounted to drill for this step.
The ring gear is removed from the old differential carrier and installed on the new ARB Air Locker differential carrier. You may have to heat the ring gear in hot water or in an oven to 175-212 degrees Fahrenheit to help in aid in this step. We then torque the ring gear bolts to the proper specifications. Be sure to use Loc-Tite 290 on threads before tightening. When installing 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 (passenger) side. The replacement bearing and shim pack is used to accommodate the seal housing which the copper tube runs out of. Install new bearings and shims on the differential. New bearings are good insurance for your new Air Locker. It is very convenient to replace the bearings while you have the differential apart anyway. Be sure the bearings are fully seated, and don't interfere with the air inlet collar. Once the bearings are in place, place the locker in the carrier housing and install the left cap but do not tighten. The seal housing tube on the right is set so that it's protruding straight out. The O-rings are lubricated with oil prior to assembly. The driver's side bearing cap is then marked to be notched. We found a cut off wheel to be a quick way to do this. After the cap is notched, it's installed and the caps are tightened.
The gear lash is checked by painting gear marking compound on at least 3 of the ring gear teeth. If re-using gears, it is best to try to match the pattern the gears had originally. With new gears, set them up to manufacturers specifications, which will mean the gear contact patch is centered on the teeth. When the pattern is right, torque the bearing caps and install the adjuster retainers. Apply pipe sealant to the bulkhead fitting and screw it into the hole you tapped earlier. Run the copper tubing from the differential to the bulkhead fitting. Install the copper tube in the bulkhead fitting using the supplied hardware. Care must be taken not to kink the copper tube. A final check was made so that it doesn't interfere with any objects. The axle shafts are installed next. Before we proceeded to install the rest, the ARB was manually tested using a spare piece of plastic tubing and our tool compressor which was set to 90psi. When air is compressed inside the differential, the ARB should be locked and both shafts should spin at the same time. After the successful test, the rest of the axle is re-assembled and gear lube is added.
Now it's time to install the compressor and electrical system. The compressor comes with a nice wiring harness and all the hardware necessary to mount it which makes the installation easy and professional looking. The compressor happened to fit perfect on the driver's side inner fender so we mounted it there. Since it was close to the jack, we made sure the jack could be removed with the compressor mounted in place. A mounting plate is supplied to give additional support to the mounting surface. The fact that ARB supplies all necessary hardware makes mounting the compressor one of the quickest parts of the installation.
Once the compressor is in place, the blue air line is routed. The line needs to be placed out of harms way, and must allow for axle droop. The air line is arguably the most vulnerable part of the locker, so take care in routing it. We made sure it wasn't touching sharp edges or any hot areas. Air line failure is most commonly attributed to the routing the line close to heat sources. The blue line was zip tied to several parts to avoid any problems. This routing should also protect the line from any trail hazards. Both ends of the blue line are fitted with the ARB fittings and installed. Once the air line has been routed, it's time to finish the electrical connections. The wiring harness comes in two pieces to allow the harness to be routed though the firewall. A neat feature of the harness is that it includes provisions for two Air Lockers. This easy work when adding a second ARB locker since you just have to plug in a another switch and second solenoid. To mount the switches in the dash, an aluminum piece was used which and is mounted in the ashtray. A rotary tool was used to cut the square shaped switch holes in the aluminum. This provides an "out of site" location when driving on the street but it's still within easy reach when the trail gets rough. This also prevents someone from accidentally bumping the switches. The ARB supplied switches are very attractive and includes lighting for easy to locate switches when driving at night.
We only installed the ARB in the front axle. If ARB made one for the 14 bolt full-floater, it would of been installed at the same time. They do make one for the 14 bolt semi-float. From what we hear, they will eventually make one available for the full float. Having a locker front and rear makes any vehicle almost unstoppable. The ARB Air Locker has a reputation for being mechanically strong. Based on the experience of this installation, it is clear that in order to take advantage of the mechanical strength, the air system must be carefully installed and protected. If not installed properly, failure could occur and/or the air line may be vulnerable to trail damage or wear. Also, the o-rings inside the differential can be easily damaged during installation or by debris in the differential oil. The installation is no more difficult than any other locker installation. Even though more steps are required to install this locker, the results are well worth the effort. The ARB Air Locker should provide reliable service even in the most extreme conditions. On the street, handling quirks of an automatic locker really makes the ARB shine. The ARB in the front is almost a must if you plan on driving on icy or snow packed roads. Any other brand of locker in the front would be dangerous in the winter. On any trail, it's nice to know that you can just "flip" the switch to engage the locker when it's needed. By using an ARB locker you know exactly what your axle is doing (open or locked). With ARB's patented design, you can actually have the best of both worlds.
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Below are some advantages that the ARB possesses:
