1967 US Divers Double J-Valve Question

[JamesBon92007]

I guess this is the place to ask...

I have a US Divers "Double Constant Air Reserve Valve" that appears to match the item number of 0518-00. The tanks it is on were originally hydroed in '67. Thanks to some thoughtful person I have downloaded the US Divers manual and have the diagram and parts list So, my question is: Does the "bonnet Reserve" (the next thing to remove after the nut and spring on the reserve part) have regular threads or backwards threads? It is very tight and I'm afraid of putting any more force on it until I'm sure which way it turns. This particular valve does have backwards threads on the manifold and one US Divers K-Valve I had has backwards threads on the valve bonnet.

The valve appears to be in very good condition but the reserve does not seem to work properly--it will allow air flow at 100 psi in the "Start Dive" position. It is stamped 500 psi.

Thanks.

 

[duckbill]

All of mine are right hand thread. They can be a real PITA to get apart. Try dripping vinegar in the threads and let it soak for a while. Keep checking to make sure the threads stay damp with vinegar until ready to try disassembly.

Some of the nuts are large enough in diameter that you will not be able to get a socket all the way down on it, and you can end up rounding the brass hex points quite easily. Just take it easy. If you are lucky, you may have one of the smaller diameter bonnets that a deep socket will fit down into the body well. Then you can get full contact on the hex and it is much easier to R&R these. Only one of mine has that style bonnet, but I sure wish they all did! It might be possible to turn a socket down to fit into the manifold body having one of the larger bonnets, but I have not tried that yet. (Captain?!)

When you do go to put it back together, do yourself a favor and apply silicone grease to the bonnet threads first to hopefully make it easier to disassemble the next time.

 

[JamesBon92007]

Thanks duckbill. But, by "right hand thread", you mean to loosen the nut you turn it counterclockwise? I've never been able to keep that right-hand/left-hand expression straight in my mind. What I call backwards would be to turn it clockwise to loosen.

The good news is that I can get a six-point 3/4" socket on the nut, I just have to have the rachet to where it doesn't seat all the way into the socket. But that's OK because any damage would be to the socket or the rachet, not the nut

The valve has a sticker on it that says it was serviced by a shop in N. Hollywood. It looks to me like it was serviced and never used again--really clean with no sign of corrosion etc. But I suspect the plunger inside may have been removed. At least I have the part number from the service manual.

 

[duckbill]

Thanks duckbill. But, by "right hand thread", you mean to loosen the nut you turn it counterclockwise?

Yep, that's the way.
You're lucky to have one with the smaller bonnet.

 

[Wayward Son]

right hand thread = leftie loosie, rightie tightie

 

[JamesBon92007]

The good news is that I can get a six-point 3/4" socket on the nut.

Um, make that 1/2". I was thinking about another valve...

Righty tighty! I'd never heard that until recently, but didn't associate it with lefthand/righthand threads.

 

[duckbill]

I thought those small bonnets were 1/2", but thought maybe they were 7/16", so didn't say. If you can, you should get a deep socket for it, especially if it is really in there tight. You don't want to bend or deform the threaded spindle.

 

[captain]

By all means use a 6 point socket. Left hand threaded items are usually marked with notches in the 6 flats of the nut. That particular manifold should be right hand thread. Really tight ones sometimes need a little persuasion from a propane torch.