ARB Install

By Paul Blaik

For years one of my final goals for my Jeep's build-up was locking differentials (or Lockers).  Even more than a lift, tires, etc... Lockers have a great impact on your vehicles off-road abilities.  For those who are not familiar with the purpose of lockers, I'll briefly explain their purpose.  A 4x4 vehicle, for the most part is only truly four wheel drive in perfect circumstances.  In order to allow for turning on surfaces (where one wheel needs to go faster than the other), an "open" differential has what is called "Spider Gears" which allow for this wheel differentiation.  Off road, or in situations where traction is less than desirable these "open" differential cause more problems than good.  If one wheel has lost traction completely, (eg: in mid air, or in sloppy mud) then the other wheel will completely stop spinning, even if it's on dry pavement!!!!  Hence the need for traction devices on off-road vehicles.

In deciding which Locker to purchase, I began the same type of evaluation, research process I did with my Lift.  As with most Jeep upgrades, part of the decision if practical/functional, the rest is personal preference/opinion.  Here's why I made my decision to purchase ARB air lockers as opposed to the numerous other options that are currently available.  Lockers are divided into two types; Manual & Automatic.  Automatic Lockers are more fool proof, cost effective and believed by some reliable .  Automatic lockers such as Detroit, Lock-rite, and such use a "clutch" mechanism to un-lock the axle shaft when turning on traction'd surfaces.  For some, or for trail destined vehicles a manual locker is a very good choice.  Little to go wrong, and requires no user input to operate, however in a "daily driver" type vehicle Automatic lockers may produce undesirable driving characteristics especially for drivers in the Northern hemisphere where ice and snow are prevalent throughout the winter.  As a result I opted for a Manual Locker.  A Manual Locker require driver input to operate.  When the driver feels it appropriate, he/she activates the Locker, hence locking the axle shaft's in one or both of the axles together so 25 % of the drive power is applied to each wheel.  The benefit of a Manual Locker comes on road though when the locker is off, it operates and handles the same as the "open" factory differentials. 

Installation:  As with everything on my Jeep, I try and install as much as possible.  I did not want to hire a company to install the Lockers.  Instead I enlisted the assistance of a close friend/mechanic who is also a Jeep enthusiast... Natalie.  Natalie had the technical know-how and the shop to make this job a doable upgrade.  I was somewhat familiar with the mechanics of the install from installing my axle and gears a year prior with my buddy Ted.  So with parts, manuals and enthusiasm in hand the installation began. 




A year ago when I put together my York OBA system I did so with intentions of having ARB air activated lockers sometime in the future.  I even installed the required 90 PSI regulator so that when the time came, the OBA system would be ready to go.  I prepared the electrical and air lines prior to going to Natalie's shop.  Seeing as electrical type projects are my specialty this process took no time...  I used other peoples sites and the supplied wiring diagrams to figure out how to wire the ARB's to my York system (since by default the ARB's are normally wired to, and powered by the available ARB electrical compressor). 



Stripping everything and getting the Jeep prepped for the install went smooth.  Having a lift makes the job a lot easier.  First take the wheels off, pull the axle shafts, drain & open the differential, remove the bearing caps (be carefull not to mix them up, it's important that they get put back on the right way), carefully pull the carrier out, clean and inspect the inside of the differential and axle seals.  My axle seals we're shot in the front axle, luckily I planned on changing them and had new one's ready to go.



The ARB comes with a special Timken bearing that is used on the air inlet side of the carrier, the solenoid's, a shim kit, wrap ties, air line, bulk head fittings, a locker switch, a sticker and a manual.  You are responsible for supplying or re-using the original bearing on the ring side of the ARB carrier.  As a result make sure you have access to a press and possibly a bearing puller.
  The two trickiest part of the install are, (1) Drilling or grooving the bearing cap for the to allow for the air line (2) forming the soft copper line without kinking it, when trying to get it through the hole you drill in the differential.  I took the advise of a fellow Jeeper "Gearman" on POR and chose to notch the bearing cap as opposed to drilling it as the instructions say.  If you drill the bearing cap, you could end up doing more harm than good.  If the hole is not perfect, you could damage the copper airline resulting in a non-working locker.  The manipulating of the soft copper line turned out to be the most difficult part of the install, taking the most amount of time (especially on the front diff.  Given the angle and space limitations of the Dana 30 differential, that tube was very difficult to get into the little hole :).  Needless to say, with a little care and patients, three of us were able to get it in :D  The rear Dana 44 was much easier since space allowed for an easier install.
 


Both differentials have to be drilled and tapped to allow for the bulk-head fittings to be installed, these fittings connect the blue air line to the inner copper line with an airtight seal.  We were surprised to see that the drilling and tapping went smooth, thankfully.

Natalie got stuck with all the work that required skill, I did all the gopher work.  Let's face it, although you can't learn without experience, gears cost a lot of money, through an ARB Locker into the mix.... and that's something you don't wanna mess with unless you know what your doing.  Natalie had the tools and the knowledge, so I just stood back and watched, helping out where I could.  Randy's Ring and Pinion website provided the differential set-up specifications.  The pinion preload had already been set-up when the gears were installed the year before, so backlash was out main concern. 

Once the backlash was set at .007" on both the Dana 30 and the Dana 44, the hard part's were done.  That's where I jumped in.  Attaching the airlines and beginning the re-assembly of my Jeep.  Axle shafts back in, brakes back on, tire on, blah, blah...  Nothing too hard.  Although the anticipation of the end result and the accumulated tiredness were starting to get to me.  Here's shot's of both axles completed just prior to putting the RTV, diff covers and oil in:


Once the covers were on, a quick test to ensure all worked, and voila it did :)  But man were we tired.  The install took from 12 PM to 11PM on a Saturday with no interruptions with all the right tools, and a mechanic who knew what he was doing. 

Cost:   I was able to get the ARB's for $975 Canadian ea, plus $95 Canadian for the wiring harness, and switch harness, plus $125 Canadian for required bearings and seals.  So all in all parts cost $2,500 Canadian plus I gave Natalie's garage a bit for their equipment usage. 

 

 

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