Lock nuts on a manifold...

[Stoo]

I posted about this in another thread, but since it concerns a bit of Scubapro gear, I thought I'd ask here too!

I recently had some doubles in being hydro'd etc, and the when I went to use one set, I noticed that the centre bar in the manifold, with the isolator knob, was moving. On inspecting the two lock nuts, I discovered that both of them had split and so spun around pointlessly on the bar.

I asked the guys at shop that reassembled them about replacement nuts (which they couldn't supply) but they told me that the nuts were technically not required, and that in some circles (i.e. cave diving) these nuts were typically left loose or even removed, allowing a little give in the manifold.

I'm not cave certified, but I have been diving doubles exclusively for about 25 years, and this is the first I'd heard of this. The guy who owns the shop is a friend of mine (and former student) so I have no reason not to believe him, but I figure your opinion is best.

It is a Scubapro branded manifold, and it's probably 15 - 20 years old.

So, do I need to worry about this? Or am I good to go? And should a Scubapro dealer be able to order these two nuts?

Thanks

 

[Stoo]

Helloooooo.... Is anyone there?

 

[SeaCobra]

IMHO, you need to worry about this. Why on earth did both nuts split? I cannot imagine how this happened. In a certain, and very small, segment, of the tec community, mostly cave divers they do leave those nuts loose. However, most people do not. They position the isolation knob where they want it and then gently snug up the locking nuts.

 

[Tortuga68]

Makes me wonder if the bands/manifold width are set right...

Anyway, while it's true that some people who dive in overhead environments like them loose, so that of they bump it there's no stress, most people, in my experience, have them snugged up. You don't really want to reach back to isolate and find the knobs pointing at your ass

 

[Fishpie]

I've always left them loose with no problems.
I cannot see any way that those nuts could split.

 

[chrpai]

I'm pretty sure he was looking for the scubapro opinion. He got our opinions in the other thread.

 

[616fun]

I'm pretty sure he was looking for the scubapro opinion. He got our opinions in the other thread.

It's not a ScubaPro specific question. All manifolds have these nuts.

I'm in the camp of leaving these loose. I usually just finger tight them after I locate my manifold whee I want it. I've never torqued them down. They have never been an issue (I've owned Dive Rite, Thermo, and Blue Steel manifolds).

Those bolts splitting would be a concern to me. They should be robust enough to withstand any pressure being exerted on them if the manifold and tanks are properly put together.

 

[Tortuga68]

I'm pretty sure he was looking for the scubapro opinion. He got our opinions in the other thread.

I didn't post in the other thread so...

 

[Stoo]

I didn't post in the other thread so...

No worries... But yes, I was sort of interested in the "official" reply. I'm a little disappointed that they haven't replied to be honest. I don't really see the point in a company participating in a forum if they aren't going to participate!

I have every intention of replacing the nuts. My assumption is that the bolts were split when they were over-tightened at the shop. I know they weren't split prior, because I disassembled the set. So far, the dealer hasn't gotten a response to his inquiry about getting replacement nuts. I suppose the manifold was manufactured by some unknown company so it might be tricky to sort that out.

Someone told me that these nuts and threads are the same on all brands of manifolds. Does anyone know that for certain? That would make things easier I suspect...

 

[Superlyte27]

I'd question how these goobers got the nuts to split. That seems a feat in itself. I'm not sure its a safety issue, but I'd be pissed if my manifold didn't come back the way I sent it out. Whether the nuts are important or not (and to me, they are) I'd want them there. What happens if you ever go to sell the manifold. The buyer is going to want his nuts.