ARB locker head scratcher

Flyfish

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Oct 29, 2004
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Want to see if anyone can make any sense of this.... My ARB air line is unhooked at the bulkhead and the axle breather hole completely open so there’s zero pressure inside the axle housing. But when I drive, it’s forcing oil out of the copper air line at the bulkhead fitting.

What could there possibly be to create enough pressure to push oil up and out through the copper line? There should be nothing happening except oil splashing around inside.

Thanks much
 

discostew

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Sep 14, 2010
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Did you clean up the area annd make sure it's really coming out of the tube itself? Could it be splashing on the fittings they stack inside of the one that threads into the housing? I've got a couple apart at my shop, I could take some pictures of what it looks like in there.
 

Flyfish

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Oct 29, 2004
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Did you clean up the area annd make sure it's really coming out of the tube itself? Could it be splashing on the fittings they stack inside of the one that threads into the housing? I've got a couple apart at my shop, I could take some pictures of what it looks like in there.
It would make a puddle of oil so definitely more than splashing. I can’t say 100% from the tube itself. But I had a fitting on it, similar to a normal connection, but only a couple inches of air line that was taped off. Similar to the pic. So it was coming out of the blue line.

D5F653E6-0D55-4E23-B033-100C51397EB4.jpeg
 

Flyfish

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Figured if that much oil was going up and out of the blue line, it’s more than just getting lucky.
 

Flyfish

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My fittings look a lot different than that. I have no clue how that's happening.
That fitting/hose in the pic was just sitting out and showed the basic idea of what I was describing. I used the normal parts...


3D00034A-7A5B-4F92-BD1F-0F0C318CB758.jpeg
 
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Flyfish

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Oct 29, 2004
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Do you have the olive(ring) that slides over the copper line before it goes into the compression fitting?
Yep, and little o-ring around the copper line. Like I said, I used all the normal correct fittings. That other deal was just a convenient picture of some pieces that I grabbed to illustrate how the bulkhead had a mini air line fitted so tougher for oil to leak and wasn’t just open and oil could splash out.
 

discostew

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Sep 14, 2010
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I don't think I have an o ring on the copper line. I think maybe your not clamping down on the compression fitting and copper line tight enough. If I remember correctly, you have to clamp down on that and then feed it thru the fitting that screws into the outside of the case. If that was leaking air pressure into the housing I could see it building enough pressure inside the housing.
 

Flyfish

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Oct 29, 2004
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If that was leaking air pressure into the housing I could see it building enough pressure inside the housing.
You probably do have an o ring, the pic below should help. And regardless of fittings etc, I removed the factory axle breather so there’s just an open hole which makes it impossible for pressure to build up in the housing.. Thats why so much oil coming out of the little blue line, and on the top of the diff, made no sense to me.

E39CFD42-3982-4638-A36B-F8085FFCE16A.jpeg
 

Flyfish

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But just for clarity, there are two different setups. I have both. The fitting setup is irrelevant, but this is probably yours... 50B60314-2FFB-4AE4-8E6E-AD5E9800006F.jpg
 

discostew

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I have that one. I would reach out to ARB. I wonder if oil is in the circuits that are just supposed to be air. If that was the case the spring on the piston would push that oil out the air circuit. I have to believe it's happened before and ARB had to run it down.
 

discostew

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Found this, talking about the o rings

 

Flyfish

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I have that one. I would reach out to ARB. I wonder if oil is in the circuits that are just supposed to be air. If that was the case the spring on the piston would push that oil out the air circuit. I have to believe it's happened before and ARB had to run it down.
Good thought. That would seem like the only real possibility.. I know at one point they had issues with cracks in the housing which affected the piston and other internals.
 

Flyfish

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I put a solid cap on it just to see how bad oil wants to get out or find a different path. I’ll find out tomorrow!

And I’m gonna see what ARB has to say.
 

discostew

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I figure if the piston on the locker was full of oil it would still apply when you put air on it. But when the spring pushed the piston back it would pump oil into the air line. But it wouldn't have to keep pumping it, cause once it's dripping it could wick it or syphon it out for a while.
 

Flyfish

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Oct 29, 2004
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I figure if the piston on the locker was full of oil it would still apply when you put air on it. But when the spring pushed the piston back it would pump oil into the air line. But it wouldn't have to keep pumping it, cause once it's dripping it could wick it or syphon it out for a while.
Just figured with nothing hooked up, there shouldn’t be anything to push oil back through the copper housing seal line.
 

discostew

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Sep 14, 2010
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Just figured with nothing hooked up, there shouldn’t be anything to push oil back through the copper housing seal line.
Depends on if you applied the locker I guess. I think if it was applied the piston being returned to its at rest position by a spring, would push enough fluid to get the thing to wick oil. Once it does that it could make a pretty impressive puddle.
 

Icannap1

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Mar 3, 2015
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OC, CA
I had a the same issue on my D1 with ARB lockers there is a seal that when a little worn will allow gear oil to creep up out of the copper air line. I had replaced my vents on both diffs, transfer case, transmission, and ran them up to the back exterior of my snorkel to keep the vents clean and open while off-roading in dusty or wet areas and incase if this was the cause of the gear oil being pushed out of the air lines that go to the diffs. Somewhere on youtube I seen that being a common issue with an O-ring in the locker itself causing the issue, others have replaced the O-ring seams like a yearly thing on some and others replacing it once every 3-4 years depending on how many miles are driven. I just installed a brass inline mini ball valve you will need one for each diff when not in use close them and no fluid can creep past that point when you are planning to go off-roading open the valve and when you engage the locker the air will push the gear oil back thru the locker and engage the locker itself. I found that easier than tearing down your diff just to replace an O-ring. Hope that helps.