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70's/80's vintage SCubaPro mk5 first 109 sscond - worth keeping?

Discussion in 'Regulators' started by divergal65, Aug 26, 2012.

  1. divergal65

    divergal65 Nassau Grouper

    # of Dives: 200 - 499
    Location: California
    I just got a late 1970's/ early 80's vintage ScubaPro reg - I think it has a mk 5 first, but the second stage is definitely a r109.
    I took it out to the pool and it squeaked alot at first on inhale, but quieted down after a few minutes. I think I read somewhere these regs were originally made for 2500 PSI tank fills - I don't have any back up on that though. Otherwise it breathed fine.
    So I'm throwing this out - is this reg worth keeping for a dive trip where my depth will be within NCD limits- ~65 -100 ft. max depth? Or is it just a pool reg?
  2. herman

    herman Divemaster

    # of Dives: 500 - 999
    Location: Raleigh,North Carolina
    Properly serviced it will hold it's own against any reg you have. Learn to rebuild it and dive it.
    rhwestfall likes this.
  3. RonFrank

    RonFrank Solo Diver

    # of Dives: 200 - 499
    Location: Conifer, CO
    As long as you can get a rebuild kit for it your good to dive. I am positive that kit or the parts are currently available. Unfortunately shops love to say things like.... old as dirt, but we can sell you X. Find a different service shop, or you can go mail order. Scubatoys or TDI among others.
  4. Greg Barlow

    Greg Barlow Manta Ray

    # of Dives:
    Location: Ohio
    Bryan at Vintage Scuba - Vintage Scuba Gear at Vintage Double Hose sells 1st stage service kits.

  5. Zung

    Zung Loggerhead Turtle

    # of Dives: 500 - 999
    Location: Geneva, Switzerland
  6. Nemrod

    Nemrod Solo Diver

    Serviced by a competent shop it is an equal to any regulator and better than most.

  7. halocline

    halocline Solo Diver

    Is this a joke? :wink:

    It's not "r" 109 btw, the 2nd stage originally was sold packed with the 1st stage as the MK5. There was no name for the 2nd stage, just a part number, 109. Pretty ironic that what is likely the most successful and long-lived 2nd stage in existence didn't even have a model name.

    Now, if you have an early version MK5 1st stage there are some issues with using it for modern diving. One is that they only had 2 LP ports, not enough for an octo and a LP inflator. Another is the lighter yoke, which as you mentioned was only designed for lower pressure tanks. However, you can probably find a heavy yoke for that 1st stage if you ask around the regulars on this board and vdh. Finding a 4 or 5 port turret is a tougher job. The 2 port turrets that I know of attached with a circlip; the later ones use a hollow bolt that is available at vdh. I don't know if they're interchangeable, I'm a little embarrassed to say, but I'd like to know! Anyhow, I suspect you would have mentioned that yours only has two LP ports.

    It squeaked because it probably has some dried-out lube around the piston o-ring; the lube dampens the vibration in the piston that is a result of air rushing past the edge in normal use. Nothing to worry about, but an indication that a rebuild is in order.

    Do a search and you'll find out all sorts of things about these classic regs. You can easily convert the 2nd stage to a balanced/adjustable reg that is the performance equal of the G250, another very successful and long-lived reg.
  8. divergal65

    divergal65 Nassau Grouper

    # of Dives: 200 - 499
    Location: California
    wow, that got some quick replies!
    In a way I was kind of joking- I've heard these regs are still used by alot of dive shops. The one I have looks like its never been used - the chrome doesn't have a singe scratch.
    So getting back to the squeaking - I haven't taken it apart yet so it might need a lube, but I have also read that reversing the spring in the 1st stage will quiet it down too.
    I'm going to try and learn as much as I can about this reg before I take it into a dive store, because I know if I go in now, they'll treat me like some total noob if I ask them the same question I posted. That's why I came here- I've been lurking awhile and its pretty civilized, for the most part :wink:.
    I'd also like to surprise my hubby who thinks he knows everything about everything , because I bought this at a divers swap meet at the LDS and he thought its unsalvageable, so we have a friendly wager - whoever wins gets first choice for our next dive trip.
    As you can tell from my sig, I'd like to go back to Truk and it would be nice to take this reg there too. The mouthpiece is a little smaller than the previous reg I had, so I definitely felt less jaw fatigue, so I 'd like to get this reg ready so it could handle some deep dives in Truk lagoon.
    I'd like to be able to use it for some 3000 psi tanks, so maybe I'll switch out the second stage - 109 and put it on maybe a newer mk 25?
    Advice anyone?
    Last edited: Aug 26, 2012
  9. halocline

    halocline Solo Diver

    Post a photo of your first stage, if you don't mind. There's probably zero reason to go to a MK25, even in truk. As long as you don't have the 2 LP port version of the MK5, it's easy to upgrade the yoke. If you do have a 2 port version, just find a later MK5.

    The 'turning the spring' bit is kind of a old school fix, but the most likely scenario is that in removing and re-installing the piston you simply get enough lube on the o-ring and piston shaft to dampen it. Once you get a picture of how these things work, you realize that air decompresses very rapidly as it passes between the piston edge and seat. It's a little like blowing air across a flute mouthpiece. Sometimes the airflow sets the piston vibrating and there's enough harmonic resonance to make it squeal. The spring really has nothing to do with it.

    I do know a few people that have used the early yoke on 3000 PSI tanks without a problem. I don't think I would do that, though, especially seeing as how it's easy to replace the yoke. I'm sure your husband is a wonderful guy, but it's probably best to ignore anything he says about regulators from now on.:wink:
  10. Wolfie

    Wolfie Manta Ray

    # of Dives: 100 - 199
    Location: Florida
    You will also find a lot of help by these same helpful people in the DIY threads. I know they helped me. I love my old reg. the other problem you may run into is in some older ones (as mine) the HP port is the same size as the LP port so you could have problems putting a new computer on it.

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