Air Is Hard To Turn On & Off

[Vintagediver]

First things first. I've had a good amount of experience working on my Voit & USD two hose regs; but ZERO experience when it comes to rebuilding or repairng any valves. The valve I'm beginning to have a problem with is The U.S.D. Constant Reserve "J" Valve; the valve which is shown in figure 3-47 (A) on page 181 of Basic Scuba the first edition. This tank and valve was originally my cousins and they date back to the mid 50's; in fact on the back side of the valve it is stamped 5-54; which I assume is a manufacture date. I acquired it several years ago; it passed all inspections with flying colors and I've been using it for the last several years but have recently noticed that it is becoming very hard to turn the valve handle (part 4 / #0501-11) when I want to turn the air on or off. I assume that this valve can be rebuilt; but I am not sure what to look for or suspect that is causing the problem. I'm not sure how soon I will do this; in fact it might be a winter project when it's not in use. I might also consider buying another one in good working order if there is one available, and use the one I have to learn from by tearing it down and bebuilding it. As always any info, warnings or suggestions from those of you who have worked on these will be greatly appreciated. Thank You! Terry

[antique diver]

Terry,
Look over a schematic, then tear into it. If you can rebuild a regulator you need not be afraid of a little old valve.

[8dust]

Well now I just feel worse...

I've pretty well got the single-stages down, and am getting better about fooling with my two stagers, but the one USD J-valve I redid leaks like it was made of sponge

air comes not just from one spot, but several... soooo good luck with that there Terry

If you get it down, come to Nashville and give me a lesson.

P.S. - good meeting you at Portage!

Fred

[Vintagediver]

Hey Fred it was good meeting you at Portage as well. As I said I haven't had any experience in rebuiding any valves YET; but I do plan on getting some. Hopefully I'll not have any problems with this one. I also believe Antique Diver has the right idea of looking over a schematic; which I've already done, and tearing into it. I'm not really concerned about tearing into it and putting it back together; I have the confidence in myself and my work to do that. The only concern I have is that after studying the schematic I am not able to really zero in on what might be making this valve so damn hard to turn when turning the air on or off. You can sure bet that I plan on finding out though. Thanks guys! Terry

[antique diver]

..... The only concern I have is that after studying the schematic I am not able to really zero in on what might be making this valve so damn hard to turn when turning the air on or off. You can sure bet that I plan on finding out though. Thanks guys! Terry

The moving parts need to be clean and have a little lubrication to reduce friction. They get dried out and dirty from age and use. They eventually need a real good cleaning up to get rid of corrosion and debris. Install new orings and possibly new teflon seals where appropriate on the shafts, all lubricated lightly with a good quality silicone grease. I lube the moving shafts well before installing orings or teflons. You will probably be surprised at how much better the valve will work after that.

As far as leaks developing, I have seen problems with that from reusing old seals and also from too little lube. It pays to watch closely during disassembly so you can be sure you get everything back in the right place. Also check a schematic... someone else may have been into it and put things back wrong before you obtained it. Give it a try, and if it doesn't work, give the specifics and ask for some help... makes for some interesting forum dialog that we can all learn from.

[antique diver]

Well now I just feel worse...

I've pretty well got the single-stages down, and am getting better about fooling with my two stagers, but the one USD J-valve I redid leaks like it was made of sponge

air comes not just from one spot, but several... soooo good luck with that there Terry

If you get it down, come to Nashville and give me a lesson.

P.S. - good meeting you at Portage!

Fred

Hey Fred, shoot a picture of your specific valve or describe it real well and I'll bet some folks on this forum have had experience with the same kind and can offer some help. Post a photo or send me one via my email button if you would like for me to give it a look.

[Vintagediver]

Thanks Antique Diver; that's some very helpful information regarding the cleaning and lubricating. I suspected that a good leaning & lube would help fix the problem; but again since I haven't worked on any valves I wasn't sure. Whenever I get around to doing this I'll be sure to post what I have found and what my results were. Terry

[swimjim]

Terry, valves are not too tough. I know you'll get it. When I am working on something that is new to me, I lay the parts out on a towel in the order of disassembly and take a few pictures of it with my little digital camera. Then I can sit in my office and compare the parts to a schematic and study it to get some sense on how the thing works.
Being in Minnesota your valve will more then likely disassemble fairly easy. If it doesn't, PB Blaster and patience are required. LOL

Jim

[Drado]

... and take a few pictures of it with my little digital camera [emphasis mine]. Then I can sit in my office and compare the parts to a schematic and study it to get some sense on how the thing works.

This is very good advice which has saved my bacon on more that a few occasions

Also, most parts for valves are relatively cheap and available. For example, a small leak from a bonnet, no matter how tight, could be traced to a re-used copper crush-washer. I also better heed my own advice and change out my burst-discs as well. I had one go off from one of my LP72s at my LDS. Interestingly, it wasn't being filled at the time, but was stored near a rack of other tanks. The disc assembly was the type with just one hole. Spun the tank around knocking over a bunch of other tanks scaring the bejeebers out of the cat... So, moral is: change out the easily obtainable parts.

[Vintagediver]

Boy do I hear ya Jim in regards to very systematically laying out all the parts. It can save you from a load of headaches later on when it comes to reassembly! I also hear you and Drado both very well in regards to getting out the ole digital camera; it's also a big help. Thanks guy's for you input! Terry

[Herman]

I use my digital camera to document dissambly all the time, it's a great resource.

Here are a couple of suggestions to improve it. First off, set your camera to the maximum resolution it has. Many (most?) default to a lower setting to give you more shots at the expence of quality. This is of little concern with photos of the kids but every megapixel you can get gives you better detail that you will want when you go to enlarge the screen to see just how that part was installed. Shoot lots of photos at different angles and close ups. Take photos of sub assemblies as they are removed, not just of the parts when they are completely dissambled and then take photos of the subassemblies with all the parts spread out in order. I also take photos of the parts and subassemblies as I put it back together. If it works great, I have better (cleaner parts)shots for future reference and if not, I have shots that I can compair to the originals to look for issues before I tear it back apart.

[swimjim]

The camera setting that will yield max resolution is called Macro. If you own a Cannon Powershot, that's the little flower symbol. Watch your lighting when shooting super close. Sometimes a flash will overpower things, especially on shiny chrome parts.

[captain]

In some cases the problem is external and can be solved by removing the on-off knob and cleaning away verdigris and any dried salt deposits.

[Gilldiver]

In the download sections under US Divers is a slide presentation I did on a USD J-valve. It has all the exploded photos you should need.

Bigest thing is on the J-valve side there are a few o-rings that have to be replaced.

[captain]

The older valves with the wing nut type on-off don't have any O rings other than the regulator to tank. They use only Teflon washers.