Scubapro M5 reassembly

[phgachoud]

Just bought a scubapro M5 and missing schematics.
Am trying to understand how this guy is built, and above all trying to understand what's the "cracking effort resistence bolt" (the black plastic piece on the right of the barrel with a knot written dive clockwise) is supposed to be attached to the case. Am wondering if am missing a piece or if the screw is just supposed to be blocking the black knot to be pulled off the case by the barrel's spring which is the case for me, just pops out because there is no blocker for that but the 2 o-rings or friction between the o-rings and the case !?!!

I Just dont get it...

If you read this tread could you share your thoughts about this 2nd stage? performances, maintenance reviews, anything?

Thx!

 

[Tanks A Lot]

The Polar or M5 from ScubaPro has a clever spring adjuster.

I'm not entirely sure I understand your question, but it is correct that the black barrel pops somewhat out when turned to the dive position. This lessens the preload on the spring, while the pre-dive position is the retracted barrel, which puts extra preload onto the spring.
However it should not pop out of the housing completely. The pictures are a bit fussy, but it looks like you have it set up on correctly on the M5_1.jpg picture. The screw is supposed to block the the barrel from escaping, but there should be a tiny cam lobe on top of it, which I do not see from the pictures (Or I just miss it). The cam follows the contour of the housing.

The service manual explains excellently how this is supposed to be setup, I'm sure you'll have a much better understanding after reading it, rather than my poor explanation.

 

[lexvil]

Totally unfamiliar with this stage but looking at the manual and your pictures it appears to me to have been modified and the combination of differing parts mat not be compatible. It’s interesting for sure.

 

[phgachoud]

The Polar or M5 from ScubaPro has a clever spring adjuster.

I'm not entirely sure I understand your question, but it is correct that the black barrel pops somewhat out when turned to the dive position. This lessens the preload on the spring, while the pre-dive position is the retracted barrel, which puts extra preload onto the spring.
However it should not pop out of the housing completely. The pictures are a bit fussy, but it looks like you have it set up on correctly on the M5_1.jpg picture. The screw is supposed to block the the barrel from escaping, but there should be a tiny cam lobe on top of it, which I do not see from the pictures (Or I just miss it). The cam follows the contour of the housing.

The service manual explains excellently how this is supposed to be setup, I'm sure you'll have a much better understanding after reading it, rather than my poor explanation.

Thx a lot for your informations and schematics I was missing! I definitly miss the cam that's what I was wondering, not being normal a screw going directly against the plastic. I'll figure something out to make that work as expected! been amazed by the strength of the spring BTW, wondering how this guy breathes and above all its cracking effort... seing the manual it should be to reach a 1.2" of cracking effort...

Is that guy even blanced? I dont think so, or dont understand how it is...

 

[josb]

Oke I attached also a file, Tanks a lot attached the files from the M5 Polar but what you have there on your table is a M5 (not Polar), the biggest difference is the metal housing number 27 compared to the plastic housing of the Polar also number 27.
But he is right about the missing part.

What I can see from the photos is that on your part number 32 adjustment knob there is a little screw number 29 (and probably also the nut number 31) but I miss the piece called ring number 30 which would be screwed on with that little screw this is needed to lock the adjustment knob in the housing.
So the adjustment knob should be pushed in against the spring pressure and the on the inside of the regulator you have to screw in part number 29 together with number 30, this will hold the adjustment screw in position

 

[axxel57]

I'm a bit late, josb made already some correct points, but here my comment.

The M- Series of SP has always been a bit underestimated, they are fine breathers and very reliable.

In 1989 the first M5 Model came in Europe on the market, it was basically a G200, but with a Dive/Predive Switch (not an adjustment knob) .

The housing (barrel) was metal and there was no Venturi Vane, and the orifice was metal.

There have been some modifications to the original M5, until in 1993 the M5 Polar was introduced.

It was supposed to protect the 2nd against icing as the model name indicates.

It was (is I guess) the only unbalanced 2nd with a ‘Micro Adjust’. This is why these 2nd can be adjusted very light.

The barrel was plastic now, the two holes in the case ( we know them from the R190s) fixed the barrel ( the later M50 had only one) in the case.
The mechanism of the ‘Micro Adjust’ is quite unique, but works very well if good lubricated.

To get the screw fixed, that held the adjustment mechanism in place, was still a PITA (was finally made much easier with the M50 which entered the market 1996).

So, since the OP has clearly a metal housing and the Predive/Dive switch without ‘Micro Adjuster’, but later cap design ( the case looks like to have one hole what for ever ) it could be the 2nd Gen. of the original M5 from the early 90ties.

Anyway, it looks, as TAL mentioned, that the cam lobe is missing.

I’ll check tomorrow, if I can find one in my fundus.

 

[axxel57]

M5 Polar...

 

[josb]

Axxel57
Your picture p1320272.jpg shows a broken part so you have the missing part number 30 available for the topic starter hahahaha

 

[axxel57]

Yes, just that no broken parts are shown.........

 

[josb]

I never realised that the inner part of the adjustment knob (where you can do the fine tweaking) is a two part piece.
I don't get so often a M5 on my desk, guess I had 1 in the last 10 Years.