ARB locker issue

[Woodscaper]

My rear ARB does not always ingage! the compressor is working, the locker switch is working, the line holds pressure, but still the rear end does not lock up??? Any suggestions would be apperciated, Thanks.

[Geno]

Pull the housing vent tube off listen for air escaping. If air hissing can be heard you rolled or tore the "O" ring off the engagement gear, I did it once. Air lockers should only be engaged with full 90 psi in the line and vechile not moving, when engaged with less than operating air pressure the move gear trys to move to engage but jerks back and forth some and rolls/tears the "O" ring, and yes it has to come all apart to replace it. the part is not real expenisive , just the labor part is. If no hissing is heard the unit needs to be inspected for the engagement gear jammed / tweeked in the housing ( engageing switch while 1 wheel spinning and the other not) those are the only things I have seen to cause a air locker to not work, oops, there always is the engae gear is broken also, Burn-outs on pavement or on rocks. I have owned 2 air lockers and the 4 runner in my garage has 2 in it also. My best guess:2c:

[Mporter]

This happened to the ARB in Pete's rig, I still don't know if he got it fixed.

[Brody]

What Geno described is the state of my rear 2000 Taco ARB. I noticed this when it did the same thing, pulled the vent line and found air coming from it. That means the O rings are toasted.

When I had another ARB over here with and engagement problem, i pulled the line to check to see if it was getting pressure. It had oil in it , but was also getting air. Just not enough. I pulled the line at the compressor, leaving the line off at the diif, and pumped carb and choke cleaner or brake cleaner through it until I got rid of the oil. I then checked the diff fluid as either too little or too much will adversely affect the ARB. I then buttoned it all back up and all was well.

You may also have a crack in the air line that runs to the back. If you are running the ARB blue lines, these are notorious for getting a crack right where they come out of the fitting, either on the compressor or differential side. This is easily fixed by simply clipping a bit of line off and reinstalling the fitting.

Most of the times, it is the external stuff rather than the internal with the ARB. If you have air coming out of the diff vent line, then you are dealing with the internal junk and probably the O rings. Check everything else first

[RidgeRunner]

What Pete said. The ARB that was in my old Jeep would start acting up and I was because gear oil would get into the airline. Pulling the line off at the diff and turning on the compressor would clean the oil out of the line as a temp fix. Only had to do it every couple months. The current owner called me yesterday asking some questions about the same problem. Prolly just needs new O rings.

Check the easy stuff first before you tear into the diff.

[Alpine Spirit]

This would be odd and rare but once on Cliffhanger in Moab I had my bare arb blue line pop my retainer strap and then it got just close enough to melt and seal it shut perfectly. It didnt leak but when we pulled it off the diff no air came out and we tracked it back about 6 feet. Put in a splice and on we went.

On a side note you can get 5mm splices from fastenal insanely cheap. Just buy a whole bag, same price as an ARB fix kit.

[Woodscaper]

Ok thanks for the ideas. If I do end up tearing into the diff, is it like installing it all over again? Or do I just need to make sure it goes back together the same way it came out???

[Molley]

it goes back together just like it came out no shimming cause you arent changing gears and also a good time to drill a drain hole in bottom of housing if you dont have one ,, do you smell burnt oil under hood or see a liittle puff of smoke or is hood a little wet right above your compressor when you switch unit off ? = oil in line i have same trouble . i blow oil out of line and all is well for months .. fun times arb

[Woodscaper]

I finaly getting around to looking at the ARB, The line holds pressure and no air leaking from the vent tube. I pulled the air line from the diff housing and blew it out. it seems to have oil in the air line inside the housing. How do I clear the line from the housing in to the actuator??

[Brody]

For the last question (which actually is something that happens with ARB lines on a more or less regular basis), take the lines off at both the axle and the compressor ends, then take brake or carb cleaner (carb cleaner works best), stick the little red hose that you always lose down into the line and keep shooting it in in spurts until the line blows clear. Then shoot some compressed air down the line from a separate air source. This will clear the line(s).

I just recently did this on Alex's Jeep and he had been experiencing the same issue. All it was was a clogged line that diff oil had backed up into. The lines are so small and the oil so thick, that the compessor switch will register that you have 90psi and cut off, all without any air getting back to the differential.

My rear Taco diff ARB has the more expensive and PITA problem that Geno described...Plenty of air getting to the diff through the line, it just happens to blow right out the vent tube....O Rings...and not a clever design on ARBs part for an easy fix...

[Woodscaper]

I cleared the blue line, but what about the copper line inside the diff ???? Will the carb cleaner ruin the o rings ?? or will the o rings seal the carb cleaner from entering the diff. ?? Can I just hit the fitting with the air gun and blow it out ?? Dumb ?'s, sorry dont want to EF up the $700 POS/ARB

[Woodscaper]

I just blew it out with some air, I hope it works.

[Brody]

Good question. In my experience with the ARBs, what I described with simply clearing the blue line works well. What I wouldn't do is to force air down into the copper line past the 90psi mark, which is all the psi that the compressor will do, anyway. In which case, simply hooking up the line from the compressor will do the same thing. Bowing the O rings inside the ARB, well, simply blows, to say the least, and you enter a whole new realm of ARBness that you don't want to be in. As far a screwing up the ARB other than the internal O rings, it would be pretty hard to do as they are stout units.

If anything, I would do two things in this order (unless Geno provides something better. He is better than I am with this stuff...):

Before you hook up the blue line to the axle, get both rear wheels off the ground and spin the tires to see if you can't 'burp' the copper line clear. This may or may not do a damn thing.

Still with the rear wheels in the air, hook the blue line up, actuate the compressor, and then spin the rear wheels by hand. Deactivate the ARB compressor, take the blue line off again and see if the line got more diff fluid in in. If it did, clear the line like before. Note: if this is the case, you may want to drain a little diff oil from the diff. The ARB takes up a lot of room and thay are real picky about how much fluid makes them happy...Too much doesn't work nearly as well as a bit low with the ARBs..

My guess is that simply clearing out the blue line of the fluid blockage will do the trick.

[Jim]

Air lockers should only be engaged with full 90 psi in the line and vechile not moving, when engaged with less than operating air pressure the move gear trys to move to engage but jerks back and forth some and rolls/tears the "O" ring, and yes it has to come all apart to replace it.

Engagement into taken to heart. What about moving/not-moving for dis-engagement? Does it matter re o-ring "roll" / issues if moving when it disengaging?

[Woodscaper]

Well I blew out the line as I stated above, Road tested it and still not engaging. I tried foward and back as well as no load but it stil would not lock up. I have not checked the psi of the air line yet but that will be my next test, to make sure the compressor is working properly. If that checks out I will need to tear into the center section and inspect the damm thing. I gatta learn how to sooner or later I geuss. Thanks for the suggestions.

[Geno]

Hello, when disengageing, turn of axle switch off and then drive straight as possible for about 1 tire revolution, the engage gear should slide easyily move into the free wheel position. If the truck is in a bind - drive out of the bind with the ARB still "engaged", if you un locked it in a bind on it -it will clunck/snap/pop as it disengages,. that is not good,hard on gears and the case itself, I have had air lockers since 1988 ( bought first one from Jerry at Predator 4x4 when he had to buy his first 25 air lockers to set up his distributorship, cost for a dana 44 then about $393.00 ) My little tweaks are what I have found keeps ARBs working and working on demand, considering I just bought my first jeep with front and rear ARBs,( my 4th and 5th air lockers ) I will use this knowlage to keep these units working for years to come. Another item, ARBs like clean oil, if it gets contanmaned , change it as soon as possible ,they do not like dirt or water ( tears & nicks those small "O" rings on the bearing for the engage ment gear) as for the copper tube, Pull the blue line and clean it out, carb clean OK ( NO BRAKE CLEAN) I do not know if the rubber seals in the ARB are rubber or polyurathen ,( factory ARB / aftermarket) and air ( 90-95 psi, never higher, that will blow out the "O" ring) then re attach blue feed line, air up compressor and engage, and roll wheels and see the rear wheels engage ( sorry ,Axle in air) and dis-engage a couple of times. If all works well great... get your favorite drink.. If still does not work , pull the cover and re-do test, the "O" rings need some kind of oil/lube to seal in the air so do not clean the ARB , just do engage / dis-engage test again and hopefully you will see the problem. If it still does not engae , double check the copper tube is not damadged ( smashed flat/ kinked) , if it still does not engage ,it needs to come out for a bench test . there is a hole that goes from the bearing, "copper tube" is attached too, into the center of the ARB to move the gear, dirty oil and contaminints have been know to get in there, and block the air way. I know this is long and I did not have spell check, but, I am trying to give you the most complete service test on a ARB, this is the way I do the ones I work on. side note, MY first 2 air lockers, front and rear dana 44s in my 1973 bronco, I know broncos very well had them for over 21 years. If you have any questions feel free to PM me, help for Front range 4x4 members is always good.

[Woodscaper]

Thanks Geno, this is helpfull info. I will carve out some time to dig into again.

[Serious Offroad]

Sounds like a bad/worn-out engagement ring.

You'll have to open up the locker to tell though.

Pics if you do.

Let me know if you need replacement parts as well.

[Geno]

Hello, I saw 2 questions on how to install new "O" rings into the arb airlocker. When you do the first set- up of the air locker, you install the unit with bearing pre-load then install the "O" rings on the final re- assembly.So "no" you do not need to remove the bearings. to replace the "O" rings only, Here is how , Drain oil, take apart what ever is needed to get the axles removed, un hook blue air line from the top/front of housing, remove outer compresion nut and Ferrule, remove cover or if pumkin unit(Ford 9in, toyota) pull the pumkin out, unbolt main bearing caps, depending on how tight the case preload is ,you might need a case spreader, or you might be able to get the case out by prying the air locker out,(( 9in unturn lock rings , do not forget to mark lock rings so when reassembling they are in the exact same position to keep preload and backlash correct)).. ( BE VERY CAREFULL REMOVING CARRIER) as you pull it out a second person helping needs to guide out the seal housing( where brass air tube hooks to case) the shim pack and the master shim and keep them together and in order ( do not forget which way the brass tube faces). When unit is out you remove master shim , then shim pack ,then the seal housing , then the bearing race, you now have access the "O" rings, You do not have to remove the bearing , next CLEAN , then clean again, Look very closely for any, dirt nicks, sharp edges, burrs, and any parts of the old "O" rings, This is right out of the install manuel (next Lubricate the "O" rings with oil (NOT GREASE) then stretch them over the bearing journal and release them into the grooves) DO NOT ROLL THE O-RINGS into the seal housing as this will damadge them. place on the bearing race, next install the seal housing over the "O" rings by gently applying a downward twisting motion, this will alloy the "O" rings to gently engage. assemble the cleaned and re assembled shim pack and the master Shim ( thick end shim). Get your second pair of hands to help hold the brass tube straight out of the housing and put on the shim pack and master shim and drop carefully into the housing , if you are using a case spreader ,releaese spreader now, if not ,,and you need to tap the case down because of the preload, carefully use a brass driff and hammer and only tap ONLY on the bearing races, NEVER on the seal housing!! (( 9in move the lock rings back to the pre marked positions)) reinstall bearing main caps and re-torque to spec. slide in axles and do a function check right now once or twice is all you need (( 9 in test and look into openings )) If all is well finish putting it all together. This is assuming the "O" rings are /were the problem. If upon disassembly there is metal parts in bottom of housing or visiable case damadge a different process will be needed to diagnose the problem with the ARB. I have never put air to a arb while on a bench, It can be done to check for function with the seal housing over the "O" rings ,but there is a chance the seal housing might try to pop off the arb, so make sure you have a way to hold it on securly, remeber you are putting 90 psi to it, when you air down to only 15-20 psi it keeps your tires inflated with your whole truck on them.SAFETY FIRST. I know again this is very long and I still do not have spell check here, But I hope this helps.
Gene

[Geno]

Hello, all, I was informed the above "O" ring install is only for the Dana 44/60 applications, since I do not have a ARB in a toyota or ford 9in ( pumkin type unit) I assumed they were all the same type set-up. I am sorry that I put up some incorrect information. You will have to pulled off and pressed back on the seal housing with a bearing puller and press on unit, I believe you still do not have to reset up the unit and the preload and backlash should not change from the "O" ring replacement. Gene

[Brody]

You are forgiven, Gene. We still love ya!

Mine is going to a local drivetrain shop for the press off/press on treatment. I will run some gear lube to double check backlash, but that I can do....at least on a Ford 9" and Yota stuff....With mine, it is only the outer over sleeve on the bearing that needs to come off, so checking the backlash is redundant, but to me, it's like re-torquing lug nuts when the wheels have come off, only more work to get to. Mine has already been all the way apart one, sans stripping the gears off and looking at it now, my gears are still very happy. I can't believe the older 94 V6 axles and gears compared to the axles and gears in the newer Taco rear...with the same engine, too....Beefy. (Not you, Jeff!)

[Beefy]

You are forgiven, Gene. We still love ya!

Mine is going to a local drivetrain shop for the press off/press on treatment. I will run some gear lube to double check backlash, but that I can do....at least on a Ford 9" and Yota stuff....With mine, it is only the outer over sleeve on the bearing that needs to come off, so checking the backlash is redundant, but to me, it's like re-torquing lug nuts when the wheels have come off, only more work to get to. Mine has already been all the way apart one, sans stripping the gears off and looking at it now, my gears are still very happy. I can't believe the older 94 V6 axles and gears compared to the axles and gears in the newer Taco rear...with the same engine, too....Beefy. (Not you, Jeff!)

My ears were ringing. :D