Leaking Scubapro Mk2 1st stage. Thoughts anyone?

[whaylonsmithers]

Hi All.
My Mk2 First Stage is bleeding air. In the diagram with the red box the air is coming out of one of the holes. It is only noticable when I put it in water (ie can't hear or feel it out of water). A bubble forms on the hole, then trickles out at rate of about 2 per second. It only comes out of one hole. I'm not sure if changing the orientation of the regulator changes the hole it comes out of. Its about 5 years old, ex-rental, lightly worked for a rental and probably never had a service. I know it didn't get a rinse every time it went for a swim, including some hot days in the sun. Grrrrrrrr.

I'm not diving it and I'm not DIY-ing it. I'm interested in fault finding so I sound a bit knowledgable when I take it in for repair. Looking at the exploded diagram it seems to me the problem might be damaged a o-ring on the wide end of the piston (part 24, right hand side). Oh, and that it needs TLC in general. Any thoughts from the forum? THANKS VERY MUCH FOR ANY COMMENTS.

 

[herman]

Odds are it just needs a rebuild which will replace the orings and lube the reg. There are 8 or 10 possible causes of the leak and it's pretty much impossible to determine which without it in my hands. The most likely are, oring 23(24? -it's the unnumbered part on the far left of your diaghram) is defective, oring 25 is defective, the reg needs to be lubed (orings will drag causing them to leak), there is trash under one oring or you have damage to the sealing surfaces of the orings (unlikely). In any case, a normal service should take care of the problems, the MK-2 is a rock solid regulator. Just tell your tech you have bubbles coming out of the spring chamber and it needs to be serviced.

 

[Fishpie]

As Herman says lube it and maybe change an o ring.
The small one top left is the most likely culprit.

 

[halocline]

The only potential problem that would not be fixed by an overhaul would be if there's a scratch in the body of the reg where one of the two piston o-rings sits. It's much more likely that one of those o-rings is leaking IP air into the ambient chamber.