Problem - my ARB 3.5mm copper line (3.5mm "O" ring type) has sucked out of the bulkhead & into the diff. I suppose it happened when the temps dropped down into the single digits & the oil got thick. I thought I had blown the seals but upon further inspection I noticed the real problem.

Now the question is, why did it happen & how do I stop it from happening again!

Did the installer not taper the hole he tapped into the diff so when the fitting is tightened it won't bite down on the copper line? As in...did he over-tap it? Is that even how it works?? (I.E. tapered hole - 3.5mm line pushed through brass bung - bung tightened - bung clamps tubing?)

All that's holding the 3.5mm copper tubing in place now is the friction of the compressed "O" ring against it.

Should I buy "Bulkhead Fitting Kit, 5 to 3.5mm - #170108" as shown on this PDF doc PDF of ARB bulkheads?

Any advice, help, admonitions? I don't want my line sucking out again.

 

First, what is the REAL problem? Air leak?

Second, from your rather criptic description, it sounds like it's working the way it's supposed to. The two brass parts of the bulkhead fitting compress the oring against the tube.

Lastly, don't order/pay for the parts if you need them. Call ARB and ask them to send them to you (along with some spare large orings).

 

Firstly, thanks for trying to help TC, I appreciate it.

In reply to the first part of your question - "what is the REAL problem? Air leak?" I thought I was clear & not at all cryptic but I'll cut the text from my opening post & paste it here to clear that up: "my ARB 3.5mm copper line (3.5mm "O" ring type) has sucked out of the bulkhead & into the diff."

Obviously if the copper line isn't attached it's leaking into air the diff (or was before I put it back into the bulhead & re-attached it).

- "it sounds like it's working the way it's supposed to. The two brass parts of the bulkhead fitting compress the oring against the tube."

That answers my basic question, only the pressure of the o-ring against the 3.5mm copper line is holding it in the bulkhead & that obviously ain't cuttin' it; at least it didn't for me. I have contacted ARB btw; I did that first. I emailed them though instead of calling & I haven't heard back yet.

In my searches on the WWW I have read where this has happened to other people when the temps drop well below freezing; but I didn't find many. That made me question Why it happened, gotta be a reason & I know I had the o-ring tight enough....maybe a tad too tight. When I took it apart the o-ring was still intact but deformed from the pressure.

I'm quite sure after perusing Zuk's site, the ARB install instructions & the web at large, the only sure fix will be the pressure fittings #170108 listed in the PDF I linked to.

 

If it's pulling back through, the copper line might be too short, or you didn't have the bulkhead fitting tight enough. Mine has actually compressed the copper line.

 

I didn't install the seal housing & have never installed one but I doubt it's too short. When I pushed it back through into the fitting, the 3.5mm copper went well past the end of the bulkhead fitting....but I could be wrong.

I also had the original fitting pretty tight BUT I didn't have it as tight as it would go, I do now. I was afraid of destroying the O-ring but since I now have several spares I went ahead & put some elbow into it.

Also; I heard back from ARB, they gave timid response but they have to feel out what's going on, I understand that. I'm sure I'll have another response from them when I get home today. I'll get it figured out even if I have to put a true compression fitting on, which if I have to pull the chunk for new seals anyway (I have an air leak I haven't traced very far) I'll do.

Thanks for clearing up how these O-ring bulkheads work TC; I wasn't sure & couldn't tell with certainty from pictures.

 

Well my system held air pressure for an hour & fifty minutes today after I chased down all my leaks from installing the manual switches. The tech @ ARB says their engineers just came up with a new bulkhead & he said he'd send it to me if I wanted it.

I told him to do so if it would solve the issue with the 3.5mm copper tubing being sucked (ripped) out of the bulkhead by the cold diff oil. Hopefully it will be bulletproof.