My first mk5 ...

[buddhasummer]

This is absolutely a great DIY project. The parts I can get. There's a couple of tools you need which I can get from SCT when I'm in Thailand next month.

 

[Angelo Farina]

Guys, these regs are incredibly simple, and you just need a couple of basic tools for servicing them properly.
VDH can include the bullet piston insertion tool in the MK5 service kit.
Learn servicing it yourself, you will save money, enjoy your time, and be safe that everything was done properly (which unfortunately cannot be said of many operators in shops).
When I need to service my first stages, I rent a cylinder for one day, it is just 10 bucks or so....
When servicing second stages, I have an adaptor which allows to connect an IP hose to my low-pressure home compressor.

 

[axxel57]

Angelo
The MK5 Service kit might help for the HP seat, but the size of the Piston base is very different (022-017), better to get yourself a MK10 Kit, then you're safe.......

 

[axxel57]

This is absolutely a great DIY project. The parts I can get. There's a couple of tools you need which I can get from SCT when I'm in Thailand next month.

Buddy, I'm sure you don't need it, but in case, I would send you the Wolfinger MK10 Repair Manual and the MK9/10 schematics, for the possibillity you don't have it...

 

[buddhasummer]

Buddy, I'm sure you don't need it, but in case, I would send you the Wolfinger MK10 Repair Manual and the MK9/10 schematics, for the possibillity you don't have it...

That would be awesome, thanks a bunch.

 

[Rusty Shackleford]

Looks like the rubber on the purge cover is cracked too. VDH sells replacements.

 

[halocline]

Your first stage is a MK9, a version without the swivel turret. It is considered safer than the MK5, as there are fewer part and one dynamic O-ring less. A very nice 1st stage, probably the best piston 1st stage ever built.
it can be serviced with kits for the MK5 or the MK10, which are easily available at reasonable costs.

It is not considered "safer" by anyone I've ever heard of. You might have an idea in your own mind that the lack of a turret makes it "safer" but that is not reality. If divers were dying because their MK10 turrets were flying off and killing them, then yes it would be safer. Do you have any evidence of MK10 turrets flying off and killing divers?

"The best piston 1st stage ever built" is an overstatement. They are fine 1st stages, but I like MK5s more; they hold IP better over the long haul, and there is less IP rise at higher tank pressures. I also use my MK15s frequently because they're better with HP tanks; the bushing system around the HP o-ring reduces extrusion. I have a drawer full of MK10s, and I do use them, but not as much. There are also advantages to MK20s; they have wonderful IP recovery and extremely stable IP from full to empty tank. I don't keep them because they're more expensive to rebuild, but if I had a source for inexpensive MK20/25 seats, I would.

Point is, each of these 1st stages has their pluses and minuses.

 

[Angelo Farina]

It is not considered "safer" by anyone I've ever heard of. You might have an idea in your own mind that the lack of a turret makes it "safer" but that is not reality. If divers were dying because their MK10 turrets were flying off and killing them, then yes it would be safer. Do you have any evidence of MK10 turrets flying off and killing divers?

There was an official notice from Scubapro, asking all service centers to replace the turret retainer with the new one made of stainless steel. I doubt that Scubapro had issued such a notice if there was no risk...
This was for MK5, not Mk10, which, in my knowledge, had already the SS retainer, so no risk with a MK10.

Point is, each of these 1st stages has their pluses and minuses.

On this I agree entirely!

 

[axxel57]

It is not considered "safer" by anyone I've ever heard of. You might have an idea in your own mind that the lack of a turret makes it "safer" but that is not reality. If divers were dying because their MK10 turrets were flying off and killing them, then yes it would be safer. Do you have any evidence of MK10 turrets flying off and killing divers?

"The best piston 1st stage ever built" is an overstatement. They are fine 1st stages, but I like MK5s more; they hold IP better over the long haul, and there is less IP rise at higher tank pressures. I also use my MK15s frequently because they're better with HP tanks; the bushing system around the HP o-ring reduces extrusion. I have a drawer full of MK10s, and I do use them, but not as much. There are also advantages to MK20s; they have wonderful IP recovery and extremely stable IP from full to empty tank. I don't keep them because they're more expensive to rebuild, but if I had a source for inexpensive MK20/25 seats, I would.

Point is, each of these 1st stages has their pluses and minuses.

There is one point that might be considered 'safer 'with the MK9/10.
One of the disadvantages of the MK5s was the uneven air output of those 1sts.
While the MK5s delivered at 135bar (ca. 2000psi) 2464 liters/minute (87SCFM), they delivered at 20bars (ca. 300psi) only 1359 liters/minute (48SCFM).
The new MK9/10 design changed that at the same pressures to 2265l/m(80SCFM) and 2067l/m(73SCFM) to almost even.
That had been technically reached by making the piston head smaller and let it run in the main body of the 1st, instead of the 1sts cap.
Is that safer? Maybe.....
I doubt that Angelo was referring to that fact, when he considers the MK9 'safer', so I'm with Matt that those SP piston 1sts had their pluses and minuses at their time.
Concerning 'best piston 1st stage ever built':
It seems that the SP engineers also didn't consider those changes as very valuable, so it was not mentioned in the Catalog, and the Top Model of the SP 1sts was still the MKVII with a price more than double than the one for the MK9 or MK5 (both same price).
Still for me the MK9 are absolutely beauties, and I'm happy that I found over the time three of them in the bay for very good prices, maybe in the future I might have more competitors.

 

[axxel57]

There was an official notice from Scubapro, asking all service centers to replace the turret retainer with the new one made of stainless steel. I doubt that Scubapro had issued such a notice if there was no risk...
This was for MK5, not Mk10, which, in my knowledge, had already the SS retainer, so no risk with a MK10.


On this I agree entirely!

Ah, okay, that's right that the turret retainer nut had to be changed from brass to SS, but I don't remember that I ever have seen those SS nuts in MK5s (I will check).
I think I remember that that was an issue with the MK20s....