Mares MR22 worth rebuilding?

[Zef]

Thanks for the mine of information @lowwall, much appreciated.

Are there any special tools you would recommend? There are a few sites around such as this one, but not sure what I really need if any. I already have an IP guage and a sink full of water for cracking pressure.

I was eyeing off some MR12III sets, but will be patient and look for abyss series now.
One look in the mirror cures me of chasing style points.

No special tools are needed to service your version of the MR22, other than the IP gauge you already have. An inline adjuster to set cracking pressure on whatever 2nd stage you decide to use will make this adjustment more convenient, but it is not necessary.

If you pickup an Abyss 2nd stage, there was a revision at some point (perhaps 2008) when Mares added a port plug to the body of the 2nd stage to facilitate adjusting the nut that affects lever height. A nut drive that is narrow enough to fit through the port plug opening can be purchased from various online sources (non-dive related sources)...while its not a "necessary" tool, it definitely helps.

-Z

 

[lowwall]

Are there any special tools you would recommend? There are a few sites around such as this one, but not sure what I really need if any. I already have an IP guage and a sink full of water for cracking pressure.

You obviously already have some way of getting the yoke off and the filter retaining clip off , so that's done.

You can get by without any of the specialized Mares tools. Wooden dowels of different diameters are good for pushing stuff out or holding things at the right height during reassembly. You also need a thin probe to push the HP seat out. If you can only find a pointy one, file the point flat.

The one potentially tricky spot is a 5.5mm driver for the nut that hold the lever on the second stage. Later Mares seconds had a port on the opposite side of the case so you could use a standard nut driver like this one: Nutdriver 5.5 mm x 60

But your pre-2008 Abyss doesn't have the port, so you have to work within the reg body. Mares made a little driver for it that showed up in price lists as late as 2018. This one is from 2007.

If you can't find one, you'll probably have to modify a standard driver. Maybe put a 90 degree bend in the shaft and use it like a hex key?

Edit - @Zef and I were writing at the same time. He beat me to publication, but I've got him on word count

 

[lowwall]

One more thing about the tools. You'll see lever height gauges for the various downstream second stages Mares has made. Don't bother. They will get you close enough for shop rental regs, but you can do a lot better.

Here's a detailed write up on tuning these classic seconds: reply to -Needed a pony reg, was this a good purchase? (older MR12 off ebay)

 

[Ecru]

Thanks for the detailed info @Zef and @lowwall

For what it is worth I could access the 5.5mm nut in the 2nd stage with a quarter inch socket and universal joint.