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US Divers manifold stem replacement question

Discussion in 'Vintage Equipment Diving' started by Ghetto Diver, Jan 23, 2019.

  1. Ghetto Diver

    Ghetto Diver Solo Diver

    # of Dives: I just don't log dives
    Location: Beerfield Beach, FL
    624
    295
    63
    Unfortunately I snapped the main stem on 50's vintage manifold. It was moving, but more corrosion than I anticipated and..
    Does the A193 replace it ? I believe the original part no. is 0525
    Store | Vintage Double Hose
    I am doubting it as the newer part has the o ring mid body.
    Help is appreciated.
     
  2. herman

    herman Divemaster

    # of Dives: 500 - 999
    Location: Raleigh,North Carolina
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    Looking at the info I have, the part is 525-21 (there are a few other parts with 525 as the first numbers). I see the same part listed for a bunch of USD valves. The VDH page list it as the replacement for the 525-21. My GUESS is the oring was a later upgraded to help sealing. As long as the dimensions are correct and the only difference is the oring, I would give it a try, including the oring. Be sure to lube the oring a little since it's going to be sliding inside the bonnet bore.
    Tom may have some info on this.
     
    Ghetto Diver likes this.
  3. happy-diver

    happy-diver Skindiver Just feelin it ScubaBoard Sponsor

    # of Dives: 100 - 199
    Location: same ocean as you
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  4. Ghetto Diver

    Ghetto Diver Solo Diver

    # of Dives: I just don't log dives
    Location: Beerfield Beach, FL
    624
    295
    63
    Thanks Herman for the help.
    While at work today I remembered I have 2 60's era valves disassembled somewhere and may have the parts/answer.
    Short answer, the A193 will not work.
    Turns out I have both parts.
    I am going by a photo from vdh, but if it takes a 010 oring, no go. Dimensions are too narrow. The a193 is .370". The bonnet inner diameter is .453".
    There is also the issue of the face of it being too narrow when up against the bonnet stem hole.

    Thank God I am a packrat (albeit somewhat organized).
    Top is the original, then a193, and bottom is pure luck.
    20190124_165226.jpg
     
  5. Luis H

    Luis H Instructor, Scuba

    # of Dives: I'm a Fish!
    Location: Maine
    2,851
    992
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    It has been decades since I have worked on these valves, but if I recall correctly, the stem with the O-ring groove is for the reserve side of the valve.

    The other one is for the valve itself.

    Hopefully Tom will stop by and verify (or correct) this staments.

    Good luck.
     
    captain likes this.
  6. Ghetto Diver

    Ghetto Diver Solo Diver

    # of Dives: I just don't log dives
    Location: Beerfield Beach, FL
    624
    295
    63
    Yes..but it (stem with oring) appears to be a trident a193.
    The parts came from valve with reserve feature.
     
  7. Scubagaskets

    Scubagaskets Nassau Grouper

    168
    40
    28
    Catalogue - Premium O-rings Provider for Scuba Diving
    We have intermediate sizes o-rings as for example the 6.35 x 1.78 the 610 the 109 , (intermediate of the 010 and 011) the 611 that is the intermediate of the 011-012.
    See page 6-7 of our catalogue for more info.
    I hope you find what you need .
     
  8. happy-diver

    happy-diver Skindiver Just feelin it ScubaBoard Sponsor

    # of Dives: 100 - 199
    Location: same ocean as you
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    so pennington lists on his website, that the A193 replaces USD Valve Stem Part # 0525-21.
    and Fits USD Valves 0525,0530,0540

    so why are you lot trying to knock the world off its axis
     
    Ghetto Diver likes this.
  9. Ghetto Diver

    Ghetto Diver Solo Diver

    # of Dives: I just don't log dives
    Location: Beerfield Beach, FL
    624
    295
    63
    ^lol
    He also states he isn't a valve expert .
    Always good to compare if you can.

    This thing is 63 years old so slack is granted.
    I might be imagining this, but there are more vintage regulators than vintage tanks out in the wild, particularly here. Assuming lack of care, shops upselling etc.
    My shop will never see this set. Would cause too much grief.

    Also, interesting to note there are no washers between both bonnets and valve (main and reserve). The reserve bonnet was buggered sometime in its life, so maybe a monkey disassembled/reassembled at some point.
     
  10. captain

    captain Captain

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    Luis is correct. The stem with the O ring grove is for the second generation of USD J valves and manifolds. The brass stem is the 1st generation J stem. No O rings are used with either, just Teflon seals. There is also a difference between early 2nd generation shut off stems and later ones. Later ones use a combination of an O ring and a teflon seal and a different bonnet nut and stem. At one time USD had a retro fit kit to upgrade early 2nd generation valves comprised of a new bonnet nut, stem, teflon seal and O ring and I believe backup ring. I have some NOS first generation stems.

    IMG_1506.JPG
     

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