Guide to Mares regulators from 2000-2020

[Catito]

Without personally seeing/handling/inspecting your regulator it is not possible to know exactly what failed in your 1st stage....but if air is coming out of where you indicate, then it could be that the diaphragm of your 1st stage is compromised. That could happen as it is possible for this part to fail due to age/use, it could happen due to improper assembly or adjustment, it could happen perhaps due to a failure of an internal o-ring on the high-pressure side of the 1st stage.

-Z

o-ring in regulator. No charge.

 

[rsingler]

o-ring in regulator. No charge.

Did they say which one, or can you find out?
That's a diagnostic dilemma for those of us trying to figure out where a diaphragm design might leak. They should have a record of which o-ring was replaced.

 

[lowwall]

Unless I missed it, under the budget/rental category I believe the Rebel 2nd stage falls between the Nikos and the Rover.

Oops. Good catch. The Rebel appeared in late 2004 or early 2005 and replaced both the budget Nikos and the lower midrange Axis. It's actually listed under "Axis Rebel Series" in Mares 2005/2006 Service Manual so it must have quite a few parts in common. An upgraded version was issued starting in 2006 called the Rebel 2K6 to provide "increased resistance to wear and improved performance in cold water conditions." This required replacing the reg body and a couple of other parts during a service.

It looks like the Rebel was replaced in 2008 by the Rover. The Rover is based on the Prestige rather than being an updated or relabeled Rebel.

 

[Catito]

Did they say which one, or can you find out?
That's a diagnostic dilemma for those of us trying to figure out where a diaphragm design might leak. They should have a record of which o-ring was replaced.

I will ask. My guess on what happened is this...steel tanks using nitrox. O ring blows on tank while switching between dives. Crew puts o ring on—fatter than the nitrox o-ring. When I go to turn on tank right before I get up to jump in, the air rushes out my first stage. My guess is that somehow the wrong size o ring on the tank caused too much pressure to build which blew out the o ring on my regulator. Could that happen?

 

[Zef]

I will ask. My guess on what happened is this...steel tanks using nitrox. O ring blows on tank while switching between dives. Crew puts o ring on—fatter than the nitrox o-ring. When I go to turn on tank right before I get up to jump in, the air rushes out my first stage. My guess is that somehow the wrong size o ring on the tank caused too much pressure to build which blew out the o ring on my regulator. Could that happen?

Unlikely.
You are describing the o-ring between your 1st stage and the face of the valve. If this does not form a proper seal then air rushes out between the 1st stage and the face of the valve (yoke regulator) or the valve opening (DIN regulator). If a proper seal is formed then air enters the 1st stage as normal.

There is nothing about the o-ring at the valve/1st stage interface that would specifically cause an internal o-ring to blow.

It could be that the o-ring at the valve/1st stage interface was not making a proper seal and the high pressure air rushing out seemed to come from behind the plastic cover as you indicated.

If there was an internal o-ring that was compromised, it is unclear how that could happen and cause the rush of air out from the area you indicated without the diaphragm (or its position) being compromised as well...your description so far leads me to believe one of the following scenarios took place:

1. Problem with o-ring at the 1st stage - valve interface and the rush of air seemed to be coming from an area different than where it actually was coming from.

or

2. Problem with an o-ring on the HP side of the 1st stage that caused air to leak past the diaphragm on the LP side...if this was the case then my bet is that the shop tech replaced the compromised o-ring, inspected the diaphragm, and tightened the retaining nut to ensure a proper seal between the retaining nut, the diaphragm, and the 1st stage body.

or

3. The retaining nut was somehow not tight enough and the air was leaking out from between the the retaining nut, diaphragm, and 1st stage body. In this case the shop tech most likely just tightened the retaining nut to create/improve the seal.

Here is a picture of a torn-down MR15X with the parts laid out. You can see there are no o-rings on the LP side (circled in red) of the 1st stage other than on the port plugs.

-Z

 

[Joris Vd]

I use a 15x first with An ice kit. I get funny looks because I combine it with balanced adjustable seconds, but it's very stable, very little up swing and locks up super crisp and I've done + - 100 dives in water that's around 6-8 degrees C. No issues whatsoever and breathes like a charm.

For sidemount I was considering the 82x because it does great in bench tests and general cold water reviews, but the angled hp ports threw me off.

That's the thing with some Mares regulators: overall they seem very, very solid, but the small gimmicks they implement like the dual adj vane etc. make some people assume the entire reg must be a gimmick, which is not true at all.
The 72 looks a bit gimmicky with the 8 lp ports, but if you don't permanently swap out your lp ports the chance of one leaking is tiny anyway.

 

[divezonescuba]

I would like to start a discussion about the 72x and the 75x first stages. The 75xs are now discontinued in the US. There is in particular a claim somewhere that the 75x is good to 400 M. The hose routings with the 8 ports is particularly useable for backmount doubles.

 

[Zef]

I would like to start a discussion about the 72x and the 75x first stages. The 75xs are now discontinued in the US. There is in particular a claim somewhere that the 75x is good to 400 M. The hose routings with the 8 ports is particularly useable for backmount doubles.

Here is some ad copy for the 75XR that confirms the 400m depth claim:

• THE EN250A HAS REACHED BREATHABILITY REQUIREMENTS AT A DEPTH OF 400 M WITH A BREATHING CYCLE OF 62.5 L / MIN AND A BREATHING GAS OF 1.6% OXYGEN IN HELIUM (AS PRESCRIBED BY NORSOK U-101).

-Z

 

[Zef]

Did Mares discontinue the 75xr because it was a hideous looking block of chrome plated brass, or because they are pushing the 25xr which is more limiting since each of the matched pair are either right or left oriented. Both the 72x and the 75xr have 8 LP ports and 2 HP ports.

-Z

 

[lowwall]

Did Mares discontinue the 75xr because it was a hideous looking block of chrome plated brass, or because they are pushing the 25xr which is more limiting since each of the matched pair are either right or left oriented. Both the 72x and the 75xr have 8 LP ports and 2 HP ports.

Kind of a squat little guy isn't it?

Looks like the 15x body with a cold-water kit, 4 extra ports, and some questionable fashion choices.