Needed a pony reg, was this a good purchase? (older MR12 off ebay)

[84CJ7]

Going to be picking up a pony bottle, saw this was listed strangely so that when you searched for "Mares MR12" it didn't come up. For $52 shipped I think I did OK, others may disagree.
Mares Scuba Regulator | eBay
I am trusting a hunch that "stable IP with no free flows" means ready to use. You can't tell for sure from pictures, but I don't see any real corrosion and the hose looks good.
I just rebuilt my MR22 myself (abyss and proton 2nds are next) so I am familiar with Mares designs and wanted to keep the parts a bit standardized.
I am hoping I can get through at least one season with it as is before I go through it as it will then be getting the newer tri material HP seat and updated hard seat/poppet/whatever which was $33 for my MR22 (same parts) on top of the rebuild kit price. I even have a spare new 1st stage diaphragm for this (also same as MR22).

SO, some questions:
1. What version (and when) of the MR12 is this? Does it have the DFC or did that come later?
2. What 2nd is that, it looks like a plastic MR12 III second or something, which would normally be less desirable but on a pony the lighter plastic could be an advantage. I see it has the tube for the VAD system and its shaped just like my Abyss overall. Specifically what kit would I order to rebuild this?

Also for the ultimate in compact pony reg I put in a $25 offer on one of these 200 bar DIN fittings (he has 10). The pony will come with a 200bar DIN valve with yoke insert so I figured why not.
200 Bar DIN Fitting for Mares MR12 Regulator | eBay

 

[LeadTurn_SD]

Hey 84CJ7,

That should be a fine pony reg... it is a workhorse, along the lines of an Aqualung Conshelf (you can actually use a Conshelf/Titan rebuild kit for the 1st stage...).

I have one I picked up from ebay a few years ago, but it is probably the model between yours and the more recent (current) MR-12's.

I do not know what year yours is.... I bet Herman or Greg Barlow or one of the other "usual suspects" would know however.

It can use the new Tri-material HP poppet.... however the orifice is machined into the body and is not changeable like the orifice in the later model MR-12's or MR-22's.

The 2nd stage should be fine as long as the diaphragm and exhaust valve are ok. Service is simple, just a couple o-rings and a puck-style seat I believe.

Not sure about DFC... I think not with that early version, but I could be wrong.

For a pony, that 1st stage is a "keeper".... good enough actually as a primary 1st stage, but the newer Mares 1sts have better hose routing in my opinion. You could always by a HOG Classic 2nd stage to use with that MR-12 if you do not like the 2nd stage it comes with... the HOG's go on sale from time to time and are great, I just picked up 3 of them and am really impressed with the quality.

Best wishes.

 

[DiverGuam]

That should be a fine pony reg... it is a workhorse, along the lines of an Aqualung Conshelf (you can actually use a Conshelf/Titan rebuild kit for the 1st stage...).

I tried that once the other way (Mares kit in a Conshelf) , and it did not last as long as a regular rebuild.

 

[Fishpie]

I'm not surprised that it didn't work for long.
The main reason people started using USD kits in Mares was because of the poor quality Mares seat.
All my Mares 1st stages have the current blue Aqualung aeat in them.

I believe the 2nd stage is a IV .... pretty much the same as the slightly later Navy.
No boosted dfc on the 1st.
Be aware that some early 12's are "botton loaders" with the yoke nut containing all the springs and seats, rather than the typical top access under the circlip and filter.

 

[keyshunter]

That is an MR-12 IV. Late '80's early '90's vintage. I had one and really liked it for deep air. The main reason I sold it was the incredibly short 1st stage seat life and (at the time) difficulty obtaining seats and other parts. Nice reg--when it worked.

 

[LeadTurn_SD]

I'm using the blue Conshelf/Titan HP seat in mine.

The "new" Tri-material seats seem fine... I think Mares resolved the issues they were having with the "old" HP seat when they introduced the Tri-material seat. I'm not sure if the Conshelf seat is superior to the Mares seat anymore.

I have the Tri-material seats in all my other Mares reg sets ( 5 sets ) and all are > 3 yrs without any issues.

Best wishes.

 

[Greg Barlow]

That is an MR-12 IV. Late '80's early '90's vintage. I had one and really liked it for deep air. The main reason I sold it was the incredibly short 1st stage seat life and (at the time) difficulty obtaining seats and other parts. Nice reg--when it worked.

Yes, this information is correct regarding the model.

A few things to keep in mind, though. First, use two wrenches when removing the hose and seat connector from the 2nd stage. Using but one 17mm wrench will crack the housing extension.

Second, the LP seat is the same size as the MR12 III, not the currently produced models. Vintage Double Hose has rebuild kits that contain most of the parts for the reg.

To determine whether the DFC is used is easy once the 1st stage diaphragm has been removed. If the DFC is present you will see two holes. One will be in the center, and one off to the side. Externally, one LP port will be marked as well.

The Mares Tri-Material seat should be used. It is far more durable than previous designs.

Greg Barlow

 

[84CJ7]

OK I just went to reply and things got really long winded so I rewrote. So I can get a and MR12 III 2nd stage kit from double hose to work on this second then, does any Mares kit work on it? Abyss 2nd stage diaphragm for the III as I recall, how about the rest of the kit? I need to place and order for seat stuff again anyways.
I assume its the same screw the 2nd stage seat connector thing all the way in from the hose end and then back it out 3 turns and set lever height till there is a faint click when shaken while pressurized? That would mean I don't need any of the lever height gauges (I have zero Mares special tools)

I have rebuilt my MR22 (with seat and poppet update) but not the abyss 2nd or proton octo yet so 2nds confuse me yet.

Just to confirm with a Mares 2nd the 3 turns out thing is correct and you don't fiddle with that part after that to adjust the reg right? Someone said it somehow messes the work of the VAD system up if you do. That would mean that a Mares 2nd has only one correct adjustment and isn't tunable at all (not that it doesn't work well that way).

Question on history of MR12, when was the DFC introduced and when was the replaceable hard seat introduced. The obvious variations I have seen are small star shaped knob (the one I am buying) the later more cylindrical shaped knob, and the latest ball shaped knob but maybe thats not a consistent way to tell them apart as I have seen regs listed as MR12 III DFC for sale and this one is supposed to be a IV without DFC.

EDIT: In screwing around with my ABYSS 2nd which is breathing worse than the proton first I found that with the IP at 145 (was 160 before rebuild) seat connector 3 turns out (I found it at 4) and the lever height set to click (was tight against diaphragm before) that the purge button doesn't work, so either this thing is really messed up and in need of a rebuild or the correct lever height for an abyss isn't at the point where there is a faint click when shaken while pressurized. What is the effect of IP on lever height? More IP less height?
I may just have to order the height gauges, it looks like the abyss gauge works for the MR III also (different step) and for some reason the picture also shows "navy" for the flat back side of that gauge, which is correct height for an MR12 IV?

 

[LeadTurn_SD]

Where to start..... maybe we can tackle your Abyss 2nd. If the 2nd stage will no longer purge, you lever height is too low.

Way too low.

You need to try again.

I think Vance Harlow mentioned in his book that he had been told that Mares 2nd stages were not really "tuned".... hummmph.... great book, but that is wrong, at least for current Mares 2nds.... unfortunately the way the Mares service manual is written sort of propagates that....

I cannot speak for very old Mares 2nds, but your Abyss has a moveable orifice and adjustable lever height: That = a two-adjustment 2nd stage!!

You indeed tune it. Take the advice about 3 or 4 turns as just a starting point. Each 2nd stage is slightly different. You'll be much happier if you take the time to give it a good tuning.

Here is how I tune my Abyss (and Mares Voltrex and Protons and Rebel 2nd stages); which is different procedure from the Mares repair manual, but fairly typical and "standard" for this type of classic downstream:

Before starting, this is "the big picture": Adjusting a classic, unbalanced two-adjustment downstream 2nd is a balancing act. You are balancing lever height and orifice depth, with the goal of having the lightest spring pressure, the lowest cracking pressure and highest lever height that still results in a stable 2nd stage. Stable meaning no leaks or freeflows while the reg is in your mouth. You can expect it to freeflow vigorously if you drop it in the water on the surface, or remove it from you mouth quickly while under water.... but it should never freeflow while in your mouth, and turning it mouthpiece-down should stop a freeflow underwater or on the surface when it is not in your mouth.

Also, before you start, a warning: Whenever you turn the orifice, make sure the demand lever is depressed so that you do not "cut" the soft seat.

I start "tuning" the Abyss with the front cover and diaphragm off, and the nylock nut tightened only enough to show one thread on the poppet (you will be tightening it more, probably a couple/few turns, as you adjust the reg, but start with just one thread showing), and with the orifice backed off enough so that it will leak when you pressurize the reg.

I have the 2nd stage sitting face up on the work bench.

1.) Attach the hose hand tight to the 2nd (unless you are using an inline adjusting tool). An inline adjusting tool makes this process easy, but it is not too bad without. You just need to remove the hose each time you want to adjust the orifice, thus the reason for only attaching it hand tight.

2.) Slowly turn on the air. It should start to "hiss". If there is no hiss, back the orifice out slowly until it does hiss...

3.) Slowly tighten the orifice (turn clockwise) to just stop the leak.

Notice that the lever drops as the orifice is tightened and puts pressure on the soft seat.

4.) Tighten the nylock nut on the lever slightly to raise it back up.

5.) Now open the tank valve all the way.

If the 2nd starts to "hiss" again, repeat the above procedure.

6.) Once the leak is stopped and the lever raised back up, test purge the regulator several times to make sure the leak is really and truly stopped.

7.) With the air still on, place the diaphragm back on the 2nd stage. This will probably cause a "hiss" if the lever is all the way up... tighten the orifice slowly until the hiss stops.... this will also lower the lever.

I generally leave the lever in this position for now.

8.) With the air still on, put the diaphragm and front cover on, but do not secure the front cover, just hold it on by hand.

If there is a "hiss", tighten the orifice slowly until it just stops.

9.) Don't secure the front cover yet. With the air still on, shake the 2nd stage. You should hear a light "tapping" as the lever comes up and strikes the diaphragm. It is not a loud rattle or clacking, just a slight tap, like tapping your fingernail on an aluminum can.

Note: you should only hear this sound when the regulator is pressurized, not when the regulator is depressurized!

If you have the tapping sound, you know you have a bit of play/slack in the lever, which is correct... but is it too much slack???

10). Test by slowly pressing the purge. It should only move about 2mm before air starts to flow. More than that and you have too much slack. If there is too much slack, raise the lever with the nylock nut (clockwise).... A very slight movement of the nut moves the lever quite a bit, so just "tweak" and retest.

It may take a bit of "tweaking" to get this right.

11.) Once you think you've got it "right", go ahead and secure the front cover, and retest the "tapping" and purge distance, test breathe the reg for awhile to make sure it "feels" right.

12.) If everything is good, tighten the hose and recheck the front cover. At this point I will also do a submerged leak test looking for bubbles.

This may be a little tedious, but it is worth the effort.

Following these steps should result in a ballpark "hot" tune, at about the lowest cracking effort that is still "stable". You may need to "touch up" the tuning as the soft seat takes a "set" (forms a seating groove), or if the reg is tuned just a little too "hot". If you cycle (quickly tap the purge) will help establish a seating groove in the soft seat... I usually cycle it about 200 times, just quickly tapping the purge with the air on.

Let us know if you have questions and we can hopefully walk you through it.

Best wishes.

 

[84CJ7]

OK, so what I gather is the Mares directions and most of the special tools were designed to walk idiots through the process and leave the reg safe to use.
I played around with the Abyss a bit just to get a feel for the adjustments while the old parts are still in it. I was adjusting the nylock with a pair of pliers as my oddball 5.5mm nut driver hasn't arrived yet. When it shows up I will have to go through the process correctly and see how it goes.

It sounds like your directions are pretty universal for the Mares 2nd stages actually. I've got the hang of the MR22 and probably the MR12 1st's, once I have the 2nd's down I think I can fix most Mares regs with minimal if any instructions.

When this other reg set arrives I will look into this oddball MR12 IV second stage and see about parts. I looked at the kit on double hose and it looks like a mix of 1st and second stage parts for the old Voit mr12 which looks like a different list from whats in the Mares kits.

---------- Post added June 27th, 2014 at 10:38 AM ----------

EDIT: With a little homework (timeline in Mares catalog) I have determined that the MR12 II became the MR12 III in 1981 when they added the VAD system to the 2nd stage. And it was in 1990 that the DFC came out in the MR12 Voltrex.
If anyone knows when the removable poppet seat was added I am curious about that as well. I know there are MR12's that have the DFC and the fixed seat though so its likely a change in the most recent black bottom cap with ball knob top generation.