Mitsubishi Tech: ARB Air Locker Installation

Before I start, all I can say about the ARB locker is Wow! This type of locker is the best thing for people who use their vehicles as daily drivers. The locker uses compressed air to activate a piston, which locks the differential via a large locking gear. When the air is turned off the solenoid valve in the compressor releases the air which releases the locking ring, returning the differential to it's normal "open" drive.

The amount of extra control you have with a locker is unbelievable: hills you would have questioned going up are tackled with ease. People have even started telling me that it's no fun to watch me tackle an obstacle because I make it look too easy. Where they would find it fun to see a vehicle stuck, with it's wheels spinning all over the place, I just power through without any problems.

You must remember that with extra control you are less likely to do damage to your body and suspension parts.

A close up of the compact ARB compressor, mounted under the hood

I placed my ARB compressor in the engine compartment behind the battery using a custom plate for the compressor to sit on. The air line passes down the side of the engine compartment and into the chassis (frame) of the vehicle as it minimizes the likelihood of something hitting it and cutting the air line. It then comes out near the rear differential and runs up along the supporting beam and then down into the hard line which connects to the differential housing. I also protected the air line by running it through a reinforced rubber hose, which also protects it from cuts. To the people who wheel and are thinking about getting a locker for their Pajero/Montero all I can tell them is to go for it and you will never regret it.

The compressor, in its new home behind the battery

My first Pajero was a 1993 2.6ltr. engine with rear leaf springs and drum brakes, which uses Locker RD-46. I had ordered the locker a few weeks before I was given a very good deal on a 1993 V6 3000cc pajero with coil springs and disk brakes. The locker arrived soon after and after a few emails with the ARB Technical Dept. who were very helpful I realized that the only difference between the locker for the disk brakes and drum brakes was that the locker for the drum brakes has a Thrust Block fitted while the locker for the disk brakes does not. It seems that the axles on the drum brake vehicle are slightly shorter than the axles on the disk brake vehicles because the only reason we could see for the use of the Thrust block was that it acted as a spacer in the Differential. I placed the locker on a table and then carefully removed the 8 locking Tab washer # 150401, I then removed the 8 cylinder cap retaining bolts # 200205 (to remove the bolts you have to use a 9mm tool as the heads of the bolts are different to what is normally used) once the bolts have been removed you

The switch for the ARB blends seamlessly into the interior

lift up the Cylinder cap # 303603 and then remove the U Ring # 160305 which then exposes the internal gears. Turn the locker over and remove Flange cap # 021202, then remove the Clutch gear # 050202 which also exposes the internal gears. Once this is done you need to lift the top gears either the splined side gear # 130408 or the side gear # 130208 then the Thrust Block can be easily seen in the middle of the gears inside the piston, you then need to carefully tap the long cross shaft # 060205 until it pushes pass the Thrust block (do not push it right through or the gears may slip out) then carefully push the Thrust block through and out the piston. Carefully tap the Cross shaft back making sure that the gears on the other side do not get damaged in the process, once it is back in place re-assemble the locker in the reverse order. Make sure you use Locktite on the retaining bolts and torque to 30ft. lbs.