Mares MR22 - what happened to my HP seat?; also Q about diaphragm substitution

[spoolin01]

I bought this reg used, used it until it began to leak from the 2nd stage, had it serviced (mid-2001, seat and diaphragm replacement), and used it until it started free-flowing (Dec 2005, 203 dives later) while in Kona, so I bought an Aqualung Titan (which just started leaking 4 years later, at 170 dives).

I want to service my own regs, so I bought some kits, service manuals, read the Harlow regulator book, and just serviced my two Titans, apparently successfully, per the stable IP reading and absence of left-over parts. I'll soon be field testing the one I use under pleasant and benign Kona conditions, with any luck.

So today I tackled the old MR22. Here's what the seat and cone look like, below. There's a big divot in the seat and a small pock just opposite it on the other side - both on the seating indentation. It looks like a piece fractured and fell off. The cone is scarred at the crown, you can feel it with a fingernail, in a similar diametric pattern. I didn't notice any crud at disassembly, but I wasn't looking for it either. (Regarding corrosion/crap - it was still pretty clean everywhere after 203 dives. The Titan was worse...) Could the slight scarring of the cone have caused this, or is that another indicator that something got caught between the two? Sure explains the free flow...

Anyway, I now see that the 'service kit' contains neither the HP seat nor the diaphragm - it's basically a half-dozen $2 o-rings I guess.

Digging around I see that there's a newer HP seat available that can be had in a kit with the cone (46200705) - at least it looks to me like the cone is included for the $30. Coincidentally, the cone looks to be a close match to those in the Titans, though I didn't get a chance to look at them side by side.

Q's regarding cone: Shouldn't the cone have a sharper edge? The ones in the Titans did. If the polished crowned orofice is the way it should be, can I just polish the scarring out of the existing one, provided I can keep the rim square with the axis? I've got some extra Titan HP seats that appear to match the Mares'... Probably I'll just buy the newer Mares cone/seat kit.

I can't find a source for the diaphragm (the old one isn't cracked but a buckle-line has formed around 1/3 of the perimeter) - does anyone know where these can be had? I've got some Dacor diaphragms, but they're thinner and appear to be about 1mm less in diameter - will one of those substitute?

Lastly, the kit comes with a wafer sintered filter (DIN kit), which is what the LDS put in when they overhauled it (unless they just left the old one in). The exploded diagram shows a conical filter on the yoke reg. I've got some that should fit, and this is a yoke reg - any reason to prefer one over the other?

Thanks in advance for any helpful suggestions.

Mike

 

[Slonda828]

I've repaired an MR22 abyss and three MR12s. I have seen a regulator that looked like that inside. I think the material that mates to the HP seat just gets flaky after a while and the pressure blows it apart. They will also do that if you try to resurface them, while the U.S. Divers ones will not.

 

[dsenloe]

I do not think that I would try to use the thinner Dacor diaphragm as a substitute. There is usually a very small amount of compression before the brass parts make contact at the upper shoulder and Dacor used different stainless thrust washers for the different thicknesses of diaphragms [old style vs.new ] I suppose that you could substitute a thicker trust washer, either stainless, or nylon like USD and fill the gap but without seeing what you are actually working with, I am hesitant to give any advice. Just my opinion, any others will only add to the value of this discussion. Scott

 

[spoolin01]

Thanks for the input. In the meantime I dug through some additional gear and have found a couple of diaphragms that appear to match the Mares in size, appearance, and flexibility. I'll try one of those once I've located a new seat and cone.