ARB Air Locker Install and Update

Details...

1. When we ordered the ring and pinion set from Randy's ring and pinion service we also ordered the optional install kit. The kit contains everything you would need to set up the new gears and uses quality Timken bearings.

2. The air hole in the locker is quite small. Although the locker needs 95 psi, it requires very little volume to engage the gears. Special O-rings are placed on each side before the ring is installed to maintain pressure and stop leakage.

3. We planned on installing 4:56 ratios in our differentials and this requires a different locker. Gear ratios up to 3:73 use one locker, while 3:73 and down (numerically higher) requires a different ring gear offset.

4. A special bearing on the air ring side is needed to provide room for the airline and comes with the locker. There was one bearing left over from our install kit.

5. There is no step number 5

6. Here the ARB supplied bearing is in place and you can see the O-rings installed on the locker.

7. A hole needs to be drilled and tapped into the axle housing for the airline pass through, and for the fitting to screw into. Make sure the hole is drilled away from the ring gear, and then clean out the housing to remove all the metal filings from drilling.

8. A hole needs to be drilled into the bearing cap on the side that the airline attaches to the locker. Make sure the hole is large enough so the brass air tube doesn't touch either side of the bearing cap. If the line touches the bearing cap, it could rub a hole in the line over time and create an air leak.

9. Care needs to be taken while bending the brass tube to fit through the hole in the housing. The tube is longer than needed to make it easier to push through. Note the size of the hole in the bearing cap compared to the tube size and that it is centered in the hole so it doesn't touch the bearing cap.

10. A slow twisting motion is best when installing the o-ring housing over the o-rings. It is a tight fit and if you fold over the o-rings when installing it the seals may fail and leak air. Use plenty of lubrication on this step.

The air locker is much talked about on any trip I have been on, from “don't bother” to “I wouldn't live without one.” There are always going to be differences of opinion on any trail upgrade you purchase, but the two we find most heated discussions are lockers and tire choice. I am always amazed about how mysterious lockers seem to be to people new to the sport. They are amazed at a locked truck’s capabilities, where seasoned drivers know these are products we would not live without. With all the talk about the benefits and downfalls of ARB air lockers, I decided to try one myself. Most of the complaints didn't necessarily involve the lockers, but from the leakage of air reaching the locker.

The first thing I talked to Tim Lund about (Technical manager at ARB USA), was what type of failures he sees the most. What we found was that some drivers, when attacking a hard obstacle would have a wheel spinning in the air under throttle and hit the engage button on the locker. Well, from my experience, I can tell you you’re going to be breaking more than air lockers if you keep doing this. I have been on the trail too many times when someone starts hopping their truck on some rocks and driveshafts, U-joints and axles go snap (been there myself). To me, this doesn't sound like a locker failure but driver error (we will all do that at some time).

The main air leakage seems to come from the O-rings on the side of the carrier itself. These differentials are not the “install in your driveway” kind. Care needs to be taken when installing the O-rings. If you force the ring housing over the O-rings, the O-rings can twist and create early failure. Be sure to use a twisting motion to slide the ring housing over the O-rings along with lots of lubricant.

When drilling the hole for the brass air line running from the ring housing, make sure the hole is large enough so the tube, once bent, does not contact the sides of the hole drilled in the bearing cap. Also take care when bending the pipe itself. Make sure you pressure-test the differential and rotate the carrier to make sure the O-rings are properly seated.

One other problem area is when using an alternate air supply you need to make sure you do not over-inflate the locker. The ARB needs very little volume, just pressure. You could probably inflate the locker with a 12-volt compressor and a small tank.

The install directions are specific to the ARB compressor, and do not tell you what the appropriate inflation pressure is. Tim Lund advised us that 95 psi is optimum, yet the locker can engage as low as 60 psi and as high as 110 psi.

As an enthusiast friend found out, 120psi is far too much. He asked a local shop where he purchased it if 120 psi was all right, and they misinformed him that it would be fine. This resulted in the O-rings blowing out. Now that he reset the pressure to 95 no more leakage has occurred. We have experienced the same result with no leakage or failure for the last six months since it was installed.

What I like about the air locker that we have installed in the front differential is I have retained the full turning radius while the locker is turn off, yet at the flick of a switch (before I go up an obstacle) I can have fully-locked differentials. I find I now drive in "three" wheel drive for 90% of the four wheeling I do. Once I have traversed an obstacle, I turn the locker off. I run the locker off a 3 gallon tank (see airline upgrade in the spring issue) so I can run 2-3 days without refilling the tank. This mostly because I use my system for airing up tires as well as running air tools.

My thoughts? I think the ARB is a very capable locker, with the main drawback being cost. Also, you will need a professional to install the locker to ensure a trouble-free installation. I suggest you ask and make sure the shop you plan to use has installed these differentials before you use their facilities. Another shop may be more expensive but it will be well worth your time. Our ARB air locker has been trouble free and a welcome addition to our trail CJ.