Great ARB write up

[ChrisD]

Was trying to find more info regarding the ARB lockers, found this great thread.

Found this info very helpful

ARB FAQ

Is an ARB any less reliable than other lockers?

No, not if it installed and maintained properly. Sure, there are more parts and installation is trickier - but this true of many other components you'd never consider inferior because of their complexity. EFI is more complex, has more parts, and is more difficult to install than a carb - but no one in their right mind would choose a carb over EFI because there are more parts in an EFI system. A coil-over 4-link suspension is more complex than leaf springs - but for extreme use, it's clearly the better choice. Heck - there are more parts and greater complexity in a car than a horse-drawn buggy - but you don't see people running the Rubicon on wagon wheels!

Isn't the supplied blue plastic air line a weak link?

Yes, and it's supposed to be. It is what is known as an "engineered weak link." Yes it is weak and easy to break, because it is supposed to be. This is so that, if you snag an air line, it'll break and can easily be repaired in the field with a splice or a new ferrule in a couple of minutes. However, if you run stronger air lines (like stainless steel or hydraulic hose) and you snag a line, the line may not break. Instead you end up pulling the fittings out of the axle or the compressor. This is much more difficult to fix.

Having said that - proper routing of the air-line is critical and will go a long way to ensuring failure-free operation. Make sure you route it well, tie it down every 12" or less, and keep it away from heat, vibration, sharp edges, and the like. No two installations will be exactly the same - but common sense and a good plan will help. Routing it along-side flexible brake hoses is one good option. In terrain where there is a lot of brush, bushes, logs and other debris, abrasion damage to the line can be minimized by protecting it with a sleeve of vacuum hose or wiring loom - without loosing the desired weak-link feature.

How can I patch a hole in my air line?

Quite easily. The best way is to replace any damaged section with a new piece of line and some splice fittings. ARB supplies metric push-lock fittings for this purpose. In my experience, you can also splice a line with standard 3/16" compression fittings - the type that use a threaded body. a ferrule, and a compression nut. Since the ARB line is 5mm, which is slightly larger than 3/16", you may have to lightly sand the end of the air line with a piece of emery cloth or sand paper, to get the 3/16" ferrule to fit on - but once assembled it works quite well. Often, several varieties of air-line fittings can be found at heavy-duty truck parts suppliers or other outlets that cater to vehicles that use air brakes.

In a pinch, successful field repairs of the air line have been accomplished using epoxy, steel putty, JB weld, vinyl tube and super glue, and even the ubiquitous duct tape!

Will I / Why do I get gear oil coming up the air lines?

You should not have gear oil being forced up the air supply line. If you do have this condition - it is an indication that there is some sort of problem. A properly installed and functioning ARB will run at any angle and not cause gear-oil to come up the air line. The most common causes of this problem are:


- A blocked differential breather valve/line is allowing high temperatures to generate sufficient pressure inside the diff to force gear oil past the seals and up the air line.
- Warn, damaged, or improperly installed (twisted) o-rings in the seal housing are allowing gear oil up the air line when the air locker is unlcoked and pressure is vented to the atmosphere.

The easiest way to determine which problem is affecting you is to disengage the locker and drive normally for a week without using the locker. If you still get gear oil out the air line - a lack of sufficient axle housing venting is the likely cause. If you don't have any signs of oil after the week, engae and disengage the locker several times. If oil is now present, it indicates that the oil is travelling up the line when the locker is depressurized - meaning the seal housig o-rings are the likely culprit.

What are the most important things to watch out for when installing an ARB?

Care and cleanliness are obvious - as is reading the directions thoroughly first. In addition, special care should be taken to:

Thoroughly clean the seal housing before installing the o-rings. Sometimes excess packing grease can be present that can interfere with proper installation and operation.
Generously lubricate the seal housing, o-rings, and seal housing running surface before installing the seal housing.
Make sure the seal housing o-rings are not nicked, cut, twisted, deformed, or otherwise damages before and during installation.
Set and maintain sufficient carrier bearing preload to prevent damage to the seal housing.
Not over tighten any axle housing fittings.
Keep any and all debris, dirt, or foreign objects out of all fittings, air lines, and the locker itself.
Set up the gears properly and accurately after installing the ARB.
Carefully route the air-line away from heat, vibration, and sharp edges - tying it down securely every 12' or less.
Supply the ARB with clean, dry air between 85 and 105 psi.
Keep the gear oil clean while the locker is in service to minimize the chance of debris damaging the seal housing o-rings.


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