Old ScubaPro R109 2nd stage

[aquaregia]

I recently bought a pair of R109s with what I think are MkV first stages. Thought I was assured that they worked, one of the 109s doesn't supply air and the other has a jammed adjustment knob. Initially I was just going to write them off as a bad purchase, but I was talking to the instructor who does my college club's gear maintenance who said that it wasn't terribly difficult to maintain regulators. For background, I tend to DIY a lot of my stuff, including fencing gear, computers, my car, etc, so I'm sort of inclined to that sort of stuff anyway.
I searched around google and scubaboard and came up with a bunch of links to service manuals, etc, but couldn't find one for the 109. Does anyone have a link to it? Also, where's the best place to get replacement parts for it (or the 156, which I understand I can use parts of to convert it to a balanced rig)? The previous owner did include a bag of spare o-rings and screws, most of which do look like they're in acceptable condition.
Secondly, what's the most likely failure mode of this activity. Am I likely to cause catastrophic failure of the second stage, or am I likely to just see freeflow? Is it likely to occur immediately and predictably, like when I reach a particular depth, or within a few minutes of submerging, or is it likely to just fail randomly at some point months down the road?
Thanks
Andrew

 

[redacted]

I have yet to see the 109 that could not be saved and I have some pretty ugly regulators. When you screw up a 2nd stage, it will either leak or not breath worth a damn. It is pretty hard to make them dangerous as long as everything is tightened correctly. PM me with an address and I;ll send you some schematics. I have never seen a repair manual and it is almost too simple to need one. Parts can be a problem but if you long long and hard enough, you will find what you need.

 

[halocline]

You ARE likely to ruin the reg and could DIE. Don't take the chance! I'll be happy to step up, make the sacrifice, and take these regs off your hands for absolutely no charge!

Otherwise....
If you post a few photos, there are lots of folks on this forum that can talk you through the rebuild. The trickiest part might be getting the small screws out of the clamp without stripping them if it's really corroded. The adjustment knobs can get pretty stuck, but you'd have to really crank on one to strip it. If you have an ultrasound you can try cleaning the whole reg in it and see if that helps.

Careful with the exhaust tee and the rubber diaphragm cover. A couple of us have been lucky to find some of those NOS, but they're getting harder to find.

 

[Zung]

With apologies to my masters awap, mattboy et al, I make you a better offer: send them to me carriage forward, and I promise a world-class funeral in the Swiss Alps

If that fails to convince you, check out a great piece by DA Aquamaster here. Even though it's about the non-adjustable R108, the first half of it should get you started. Complement this with all the great informations on this board about the G250.

Question to the U.S.: my Mk5/R109 breathes noticeably harder than my Mk20/G250. It comes straight from service by a DDS (Distant Dive Shop in LA), I haven't mess with it yet. Do you think it's a matter of adjusting the orifice?

 

[herman]

With apologies to my masters awap, mattboy et al, I make you a better offer: send them to me carriage forward, and I promise a world-class funeral in the Swiss Alps

If that fails to convince you, check out a great piece by DA Aquamaster here. Even though it's about the non-adjustable R108, the first half of it should get you started. Complement this with all the great informations on this board about the G250.

Question to the U.S.: my Mk5/R109 breathes noticeably harder than my Mk20/G250. It comes straight from service by a DDS (Distant Dive Shop in LA), I haven't mess with it yet. Do you think it's a matter of adjusting the orifice?

With friend like you guys who needs enemies. Trying to con the guy out of his regs. Seriously, I agree, it's very unlikely the regs are not repairable. To get the adjustment knob loose just soak the entire thing is a 50/50 mix of white vinegar and water for 10 minutes or so, while in an ultrasonic cleaner is even better. If you can get the screw out of the cover, it's best if you don't soak the diaphragm and rubber cover.
Zung, I would start with an IP check just to make sure it’s where is should be, then yea my first guess is the orifice need adjusting. Another possibility is a stiff diaphragm, the repair shop should have caught that but you never know.

 

[redacted]

Question to the U.S.: my Mk5/R109 breathes noticeably harder than my Mk20/G250. It comes straight from service by a DDS (Distant Dive Shop in LA), I haven't mess with it yet. Do you think it's a matter of adjusting the orifice?

There should be a difference but it should be barely noticable. Start by measuring IP and cracking pressure and adjust the orifice (cracking pressure) as necessary. If that does not do it, check that there is a new seat and take a close look at the operation of the lever. I don't fully understand it, but some older metal 2nds have an older style lever that may not interface properly with a modern poppet. I always adjust cracking pressure with the cover removed and then take a look at lever height. Installing the cover may set it to leaking just a bit - corrected by just a small adjustment of the orifice. If it sets off a major freeflow, it's probably a lever problem. Another possibility is the spring may have gotten stiffer. That is pretty much a last resort and requires a new(er) spring. This is where it is real nice to have a couple of these things so you can compare one to another as you troubleshoot the problem (at least that is how I explained it to my wife ).

 

[Zung]

A truly GREAT argument to be added to the yet-to-be-started-and-made-sticky-threat "How to tell the wife"

I'm not there yet, but I can feel the menace coming, with 8 sets for a household of 4.

Thanks for the advices; I'll check them out after I'm done wrestling with the current Mk10, possibly this week end if we're not out skiing.

 

[Texfrazer]

Ah, telling the wife... My excuse is usually something to the effect that "I got it for a steal and I'll be able to e-bay it later for much more money." Of course, later doesn't always come sooner....

 

[halocline]

Question to the U.S.: my Mk5/R109 breathes noticeably harder than my Mk20/G250. It comes straight from service by a DDS (Distant Dive Shop in LA), I haven't mess with it yet. Do you think it's a matter of adjusting the orifice?

There should not be much appreciable difference if they're both adjusted correctly.

 

[aquaregia]

Does anyone have a list of generics for the o-rings, springs, etc? Looking through old posts, it seems like I can convert the 109s to 156s with just a spring and a G250/S600 service kit (true?). The service kits seem to be about $40 on ebay, but I can't help thinking that I should be able to order standard fitting o-rings (etc) if I knew the specs.