Info Servicing Scubapro MK2

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nikolay_zhelev

Registered
Messages
65
Reaction score
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Location
Burgas, Bulgaria
# of dives
100 - 199
Hi guys,

I would like to share with you my recent experience with a second hand Scubapro MK2 regulator.

The overall condition of this first stage was poor. There were external scratches on the body, light external corrosion, but what surprised me the most was the internal condition.
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When I disassembled this MK2 I found excessive amount of petroleum grease, probably Vaseline and plenty of sand mixed with this grease. Fortunately the internal wall of the piston housing wasn’t scratched.
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Before disassembly I performed an IP check on a scuba tank filled with air @ 70 bar. The IP was 155 PSI with some IP creep and the first stage was recovering the IP very slowly after purge. All data was way out of limits.


After disassembly I put all parts in an ultrasonic bath initially filled with detergent, then changed the solution to 5% Tickopur and lastly in order to make sure I’ve cleaned all petroleum grease I put all parts in 5% alkaline degreaser solution.

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The result was satisfactory.

Having in mind that the IP was out of limits with some creep, I did detailed inspection of the first stage. There were no scratched on the internal walls, but the volcano, which is machined in the main body, was in very bad condition. As Robert Singler thought me, this volcano shows signs of sandblasting.

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The first thing that came on my mind was that this body is damaged beyond repair, but I had nothing to loose, so I decided to try polishing the volcano. As I don’t have any micromesh, I decided to polish it with 2000 grit wet sandpaper. My main polishing tool was pencil. I cut small circle of the sandpaper and glue it to the pencil eraser. Fortunately the pencil was exactly the same size as the whole in the main body, so I managed to polish the volcano. The result is not great, but at least there is continious surface, which will seal to the HP seat.

HP Orifice After Polishing.jpg


After servicing and assembly, I did an IP check and… The IP is rock solid, 143PSI @ 200 bar and very sharp response after purge.

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Now this first stage is revived.
 

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Nicely done! The MK-2 is a beast, and can take a beating, usually able to be kept going despite all forms of neglect. I have some dating back to the first or second generation that I have been able to make work very reliably.
 
I have two MK2's in my school's training equipment fleet that I have had since circa 2001 and they are excellent!
 
Better than the Gillette Foamy adds.....
 
I was thinking the "roller coaster", and the "fullback"..... more in line with the time period of the Timex ads....
 
Thanks for sharing, I have the opportunity to buy a (or several) mk2 -yoke- that has just been serviced at a pretty good price used from a dive store. I am interested in learning to service my regs myself and can see service kits seem fairly easy to get still.

is it worth getting a few and diving/learning to service these? If not what is another similar reg that you would recommend as a good rugged easily serviceable 1st stage that can be picked up used easily??

(I service my own vehicles motorcycle etc... have a hard time trusting others to do the job properly. a few different places I took the motorcyloce to didn't do it right - loose fairing bolts etc.. if you want it done right do it yourself. I would make sure to get the right tools needed and do my homework, this thread certainly will be a great help - )


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