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

[divergal65]

I'll post a pic soon. A friend in our dive club wanted to check it out - she had never seen a vintage SP reg with the metal 2nd stage before - she thought they only made them from hard plastic.
In the meantime , are there any good reference books / web sites I could visit to learn more about how regs work, beyond what they taught in our OW scuba class? I especially want to find out more about the vintage ScubaPro regs. I saw one site - ScubaPro reg museum or something like that, but I'm just wondering if there are more. I guess my competitive side is showing because I want to show hubby a thing or two and win that bet!
Thanks for all the advice so far , btw...

 

[herman]

While the reg is older it is not really considered vintage, too new for that.....and it has those funny skinny hoses, a proper vintage reg has 2 big ones. The second stage is made of marine brass that has been chrome plated. It may be a little heavier than a newer plastic one but it will also stand up to much more abuse and keep going. It will still work when those plastic ones have long given up. If yours has the older thin yoke it's best if you upgrade it to the later, stronger one. That said, a lot of us have used the older type on a lot of different regs that changing the yoke was not an option on for a long time with no issues. YRMV but it has been done.

If the reg does have 3/8 (same size as the LP ports) HP ports, you can easily get an adapter or you can still buy new HP hoses with 3/8 fittings. Either way works fine and is not a problem. If you go the new 3/8 hose route I recommend you carry the adapter just in case you need to replace a hose in a hurry, the 3/8 HP hoses are not commonly stocked any more. They are maybe $7 so it's cheap insurance. I use both methods on my regs, I have a good number of them with 3/8 HP ports.

There are 2 excellent books that will teach you everything you need to know about the inner workings of regulators. Regulator Savvy www.scubatools.com is the more technical of the 2 and goes pretty deep into the hows and whys a regulator works. Maintance and Repair of Scuba Regulators www.airspeedpress.com is somewhat less technical and goes deeper into the more practical and DIY aspects of regs. IMO, both together are the way to go, combined they give you a really broad understanding of regs, how they work and what it takes to service them. When reading the technical section of both, you get the information from 2 different writers, which for me helps when I don't completely understand the theory involved. Even if you don't decide to do your own service, you will know as much about regs as 90% of the techs so when you are handed a line of BS you will know it.

Service parts are still available from Scubapro however you may have trouble buying them, shops don't sell parts to divers for a varity of reasons. You can buy aftermarket parts (and coming soon some service tools) for the reg at Vintage Double Hose www.vintagedoublehose.com The reg may be old but there is a good reason it has such a following, new is not always better and I think this is one of those times.

 

[Zung]

In addition to the 2 'must have' books herman mentioned, you may want to do a search on 109, 156 in the DIY section. You'll find an overwhelming goldmine of information.

 

[Luis H]

While the reg is older it is not really considered vintage, too new for that.....

This particular unit may not be too old, but the MK-5 design dates to the 60's...
But I know where you are coming from...

Is this a joke?

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!

It has been close to 40 years since I serviced the swivel with the snap-ring, but as far as I remember, I upgraded some of them by replacing just the swivel head. My memory of it is a bit foggy, but like most things Scubapro they were backward compatible.

BTW, the snap-ring version was very short lived. The two port with the hollow screw was around for many years.


divergal65,
In addition to all the good reading recommendations, you can also go to VDH and download the diagrams for this and many other regulator... including a service manual for your old Conshelf.

 

[divergal65]

hi everybody,

I went to my lds and got a 3/8 to 7/16 adapter for the lp port and put my current spg/depth gauge on and it worked perfectly! Yay! The parts guy there first gave me a weird look like, why would I do that, but then I showed him the reg and he started telling me all these stories about "I remember the last time I saw this reg was about 1984 in Mexico ... yadda,yadda,yadda. So I told him my situation and he said he could do the second stage - 109 - no problem, but the first stage he wouldn't touch. So I politely told him I'll try this on my own- he seemed kind of annoyed , like "what the @#$! is this woman thinking?
So here I am .
I'll keep you all updated about the progress.
I know I'll have a bunch of questions, so pardon me if some of these questions sound incredibly nooby.
It looks like I have some reading to do, so I'm ready for my next dive experience - restoring this old piece of history.
Thanks again guys,
DG

 

[herman]

Servicing a MK-5 is fairly easy, just be careful when removing orings. The most likely place you can do unrepairable damage is when removing Orings, you sctatch the seating surfaces of the piston or body. This is esp true for the small one inside the body.

 

[Zung]

So you want to let your LDS do the 2nd stage, right? If he's a Scubapro dealer, it's a good opportunity to ask him to do the Balanced Adjustable conversion like halocline said above. He'll need the poppet assembly, part #11250015, the balance chamber, #11150102, and the spring, # 01202216.

You can also do it yourself, it's actually a lot easier than the 1st stage; however, getting the parts for the conversion could be an issue. Or you may choose to leave it unbalanced: not a lot of difference in terms of breathing, but there's a possibility you have the older blue poppet with a non-replaceable seat. If that's the case, you may want to replace it with the white "Duro" poppet. Currently, there's a guy dumping a lot of original SP parts on eBay at acceptables prices, and this one is what you want.

 

[halocline]

hi everybody,

I went to my lds and got a 3/8 to 7/16 adapter for the lp port and put my current spg/depth gauge on and it worked perfectly!
DG

You mean for the HP port, correct? How many ports total, HP and LP, does your 1st stage have?

If you want to rebuild it yourself, the first thing would be to buy the Vance Harlow book, you don't need the wolfinger book at this point. It's interesting reading, but the Harlow book is the real how-to-do-it book. You'll need a few tools as well, nothing too expensive.

I'm sorry to say that it's not a big surprise that a so-called 'professional' regulator tech won't or can't rebuild a MK5, which along with the USD conshelf is one of the absolute benchmark regulators of all time. It's pretty sad. So much for the critical servicing of life support! You're certainly best off just avoiding this guy altogether and either finding someone out there who actually knows what he's doing, or learning to do it yourself.

If you do want to go that route, start with the Harlow book and then ask specific questions on the DIY forum, you'll get lots of help. The two reasonably painstaking tasks are cleanly removing the old HP o-ring and installing the new one. With the right tools it's not bad. You also need to carefully evaluate the turret bolt; it might not be a bad idea just to buy a new reproduction stainless steel one. They're ALOT more forgiving with regards to torque.

If you do the 1st stage, definitely do the 2nd stage yourself too. Consider converting it to balanced/adjustable; it's a little more money but IMO it will perform better and hold a tune better over the long run. There are plenty of experienced folks that keep them unbalanced, though, and they still work fine.

Post photos, please, if you want the best advice.

 

[Six2Life]

If you don't mind using an octo-inflator like an Air 2, you can get by with just 2 LP ports. I think you should only consider this if you already use that config though.

Although most of the time I will always recommend the DIY route, in this case having the 109 done by a SP tech may have some advantages. This is only if you KNOW the tech is competent. I'd suggest having him pretty much gut the 2nd stage and install a new balanced poppet, spring, balance chamber, and lever. The retail cost for these parts should be right around $30. Hopefully using these parts would get you out of having to buy the service kit and offset some of the cost. But since there will be 2 necessary orings not included with the aforementioned parts they may try to make you buy the kit. Call shenanigans if they do. The diaphragm and exhaust valve can probably be reused if in good shape but I think some of the really old diaphragms might not work well with the newer levers so you might want to just replace it to be on the safe side.

 

[USdiver1]

The Mk5 with R109 is a great choice for a high performance 1960s - 1970s single hose regulator. As a no cost bonus, it is one of the better looking regulators of its day so you not only get great airflow, you get it in a package that will still turn heads.
You have acquired a bulletproof combination, that with regular maintenance will last for another half century. You may also want to look into the US Divers Conshelf series (especially the units up to and including the Conshelf XIV) as well as the AMF Voit/Swimaster MR-12 for high performance, good-looking single hose regulators. I continue to dive all of these regulators, as well as a fair number of DH (double hose) units, as they are fully capable of performing within the range of recreational diving that I now engage in.