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Post by Terry on Mar 25, 2009 17:12:06 GMT -8
Now that winter is at an end (I HOPE) I have completed the restoration of The U.S.D. DA Navy Approved Reg, and the 71.2 galvanized tank that I got from my cousin last fall. The tank passed all inspections with flying colors and I thought it was all set and ready to go until I noticed what appears to be a minor leak. Just to see how it looked; I mounted the reg on the tank today and turned on the air and, while doing so I could hear a small leak coming from the valve. I did some checking and it did not seem to be coming from the seal (old nylon washer style - not an O-Ring) between the tank valve and the reg; but sounded more like it was coming from the area where the bonnet screwed into the valve body. I've never done any work on one of these valves; so I'm open to all comments and suggestions. I've checked the diagrams in "Basic Scuba" and am wondering if it's simply a matter of tightening down the bonnet more; or if it could be one of the washers that are leaking. I should also state that the valve does not leak when it is shut off; but only when I have the air turned on. Thanks for any info or suggestions! Terry
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Post by cnotthoff on Mar 25, 2009 17:26:14 GMT -8
if valve is usd (they used that teflon/nylon gasket for a few years) , i've been through hundreds of them. contact me at cnotthoff@hotmail.com for more info. once i know what you got, i can point you in the right direction.
charlie
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Post by SeaRat on Mar 27, 2009 17:30:17 GMT -8
Terry,
These are pretty simple valves. If it is the bonnet on the J-valve portion, some were sealed with an O-ring, and some older ones a gasket. The diagram I have for the USD (which I think you've seen in Basic Scuba) showed two gaskets. It is Item #28, Part #0502-08, Stem washer (2).It's possible that it is just dirt that is causing the leak. I'd take it apart and look. If you need components, it looks like Charlie has them. Good luck.
John
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Post by duckbill on Mar 27, 2009 18:16:57 GMT -8
If it only leaks when the air is turned on, I assume the leak is at the on/off valve, not the J-valve? You really should submerge the unit to locate the exact place of the leak.
Either way, there is the bonnet which you can try tightening. To use a standard width wrench you will need to first remove the valve handle.
If that doesn't stop the leak, you can remove the bonnet and check the washer. IIRC, it will be a rather thick washer that looks like nylon. It should be fairly snug on the shaft of the valve. If it isn't, you may need a new one. The shaft itself could also be worn. Clean it all up, check the mating surfaces for nicks, carefully lap if necessary (reclean), snug everything back down and recheck it.
Of course, safety mandates that the cylinder be depressurized for any valve work.
-Terry
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Post by cnotthoff on Mar 28, 2009 17:26:39 GMT -8
actually it only leaks when valve is on because the valve seat works. all those sections of valve are downstream of that seat.
no o-rings around stems of those old usd valves. if you use a washer/o-ring combo as many modern valves have, you won't be able to open valve wide enough, causing a restriction to flow at depth. on the reserve side, it may cause reserve to remain open (not hold back last 300 psi) in the up position.
i'm pretty sure i still have some of those old stem washers.
what do you guys use to remove the stem nut so you can get at the bonnet?
charlie
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Post by duckbill on Mar 28, 2009 17:40:11 GMT -8
I've been meaning to make a tool just for that, but until then I cross two screwdrivers together. Works fine but can scratch the chrome if they slip.
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Post by Terry on Mar 29, 2009 11:07:11 GMT -8
Hey guys: Thanks for all your posts, and the schematic I received from Charlie; they've been a great help! ;D I haven't had much time to look at this reg lately; but I've been paying close attention to your posts. Today I finally had some time and I was going to submerge this tank with reg attached to try to determine where the leak was coming from. For this test I was going to attach a single hose reg for the purpose of eliminating any freeflow that I would encounter if I used a two hose reg if I had any problems keeping the mouthpiece and LP diaphragm at the same level. I attached this reg, and as soon as I turned the air on I could hear a very definite leak. So; I shut everything down then checked to make sure that the reg was attached properly and that the yoke was tight and then turned the air back on. As soon as I turned the air on it began to leak again. I then took the reg off and attached my pressure gauge making sure the bleeder valve was closed, and as soon as I turned the air on I could once again hear a minor leak. I then turned the tank valve off and left the bleeder valve closed and watched the pressure slowly drop from the 2100 psi that was in the tank. I now suspect that the problem is the nylon outlet washer (part #11 in Basic Scuba); which is also the same as part #10 in the schematic that Charlie sent me. If this is the case then hopefully I won't have to tear this valve down at all. So; does anyone have any suggestions on how to remove this nylon washer without damaging it, and where to get a replacement if I need one? As always; I'm open to all of your helpful suggestions and comments. Also; it appears that I'll have some time to work on this problem since "Ole Man Winter" made a return to Michigan and I woke up to about 8" of fresh snow; after we FINALLY got rid of what we had. Many "THANKS" again! Terry
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Post by scubadiverbob on Mar 29, 2009 15:21:30 GMT -8
If you have deminsions, inside dia, outside dia, width, they would be pretty easy to turn on a lathe. I'd asume they were made of Nylon-6,6. If you have a machine shop where you live, they might make one for next to nothing. Hardware stores might sell them; though, most carry a lot of stuff in mm now-a-days. Back then even wetsuits were in inches. If you know deminsions please post them.
duckbill - could you measure the one on your dacor tank valve?
Robert
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Post by duckbill on Mar 29, 2009 18:43:48 GMT -8
Before I do that....
Terry, I really suggest you do a submerged test. The air could just as well be leaking out through the valve. At the very least, you could use some soapy water and a brush.
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Post by cnotthoff on Mar 30, 2009 10:00:01 GMT -8
have any of you replaced that washer with what used to be called a "split o-ring" ? they're about the same size as the nylon washer, flat on one side, and rounded on the side towards the regulator. i used to have a drawer of them. not sure where to get them now.
charlie
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Post by Terry on Mar 31, 2009 14:22:39 GMT -8
Well I finally managed to find the time to do a submerge test, and sure enough the leak is coming from the nylon outlet washer. I submerged the tank with a pressure gauge attached and it read 2100 psi, and carefully checked the bonnet area where the valve is turned on and off, and also the bonnet area at the j-valve reserve and no leaks. I also checked the end with the plug cap and washer, and the pressure relief plug and washer and also no leaks. The only area I detected a minor leak was where the reg attaches to the valve; so it was pretty apparent that the leak was in the area of the nylon washer. Now all I have to do is obtain a replacement and hopefully the problem will be solved. After examining the old nylon washer it sure doesn't appear that there is much hope of removing it without damaging it; they sure aren't as easy to remove as an o-ring. THANKS again for everyone's help! ;D Terry
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Post by duckbill on Mar 31, 2009 19:15:03 GMT -8
Those hard teflon seals are notorious for leaking. Too bad it couldn't be resurfaced in place.
Maybe you could remove it , take measurements and have some made. Is it so bad you couldn't dive it as it is now?
You might want to try tightening the reg on as much as you reasonably can (with the air shut off), and rotate the reg on the seal, then retighten. You might be able to get that last bit of seal that way.
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Post by scubadiverbob on Apr 1, 2009 7:31:53 GMT -8
I have access to a machine shop. Send me specs. and I'll turn you some. Just have to get teflon or nylon bar stock. I really think the original ones were nylon. Teflon would probably work. Ok, don't repeat this as gasses are given off when my specialty tool is used. Soldering Irons melt nylon. I didn't say that! I always make sure I have adaquate vintalation when I use my specialty tool. Being an electronic tech I have all the stuff to suck rosin and gasses away while soldering (just incase OSHA reads this). Just like wearing a shorty in 52 degree water (which I do quite often); I'm not recommending anyone do anything I would do.
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Post by Terry on Apr 1, 2009 17:09:57 GMT -8
Well those nylon washers are also of some concern over at the VDH website. Since I'm not the sharpest crayon in the box when it comes to computers and attaching links I'll just tell you how to find the post. Go to the VDH website; then the forum; then the vintage diving forum and check out the post: "What size o-ring for 1953 U.S. Divers J valve". I found it quite interesting, and it may very well explain why I have that air leak; not to mention that I learned something regarding the procedures that were used to attach the reg back then to avoid a leak. Since I just turned 62 recently; I guess this proves that you can teach an old dog some new tricks! I began diving back in 1963 at the age of 16 and most of the tanks by then were using the o-ring which we are now using today and I never had any experience using any of those tanks that had valves with the nylon washer; so I don't recall the procedure described in the above mentioned post at VDH. I also found Terry's (Duckbill) question interesting about the washer somehow being resurfaced while left in place; interesting idea and maybe with the right tool that could be done. ScubadiverBob also had a great idea of having these reproduced; but unfortunately I do not have the tools to properly measure this washer; nor do I want to remove mine until I know exactly what is going back in to replace it. There are enough of these valves still being used though, and I bet there would be a market for them. Thanks again Guy's! Terry
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Post by boiler81 on Apr 1, 2009 17:46:57 GMT -8
I started the thread over at VDH and would be interested in a washer if someone made them.
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