MK5 servicing problem? or misinformed tech?

[RyanNM]

I was given a used reg set (my first) by a very knowledgeable retired diver. I took it in to be serviced to a shop I trust. The tech told me that the mk5 is a model that has a piston inside that cannot be accessed, thus cannot be serviced and I need to find another. I don't think he's just trying to sell me a new 1st stage.
Is it true that some mk5's have this inaccessible piston? Or is he just not properly informed?
thanks

 

[redacted]

I was given a used reg set (my first) by a very knowledgeable retired diver. I took it in to be serviced to a shop I trust. The tech told me that the mk5 is a model that has a piston inside that cannot be accessed, thus cannot be serviced and I need to find another. I don't think he's just trying to sell me a new 1st stage.
Is it true that some mk5's have this inaccessible piston? Or is he just not properly informed?
thanks

No good tech could truly be that stupid so I would hope he is just trying to sell you another regulator. Your regulator is quite serviceable. Find another tech.

 

[scubafanatic]

There's a nice gentleman here on Scubaboard, goes by 'Couv' on Scubaboard who services 'vintage' regs (he serviced several MK 5's for me earlier this year) that you might get in touch with.

service kits can be obtained here: Shop Online

It is true the MK 5's went out of production approx mid 1980's, so all the 'hard' (metal) replacement parts quit being being produced many years ago, so IF the piston is bad or gets damaged you won't be able to buy a replacement at a Scubapro dealer (unless you get lucky and find a dealer with old stock laying around or scrounge one up on E Bay) Some people buy old regs on E Bay to use a part's donors as well.

 

[RyanNM]

Thanks for your help! I think I need to quiz my tech on what exactly he says is wrong with it.

 

[scubafanatic]

If you want it to be serviced by an official Scubapro dealer, Lone Star Scuba (in Fort Worth, TX) will service MK 5's.

 

[JohnN]

I was given a used reg set (my first) by a very knowledgeable retired diver. I took it in to be serviced to a shop I trust. The tech told me that the mk5 is a model that has a piston inside that cannot be accessed, thus cannot be serviced and I need to find another. I don't think he's just trying to sell me a new 1st stage.
Is it true that some mk5's have this inaccessible piston? Or is he just not properly informed?
thanks

LMAO, No, No it's worthless. I'll be happy to take it off your hands. . .

About as simple as a 1st stage can be. I'm amazed at the machining work it would take to reproduce something like this, but a rebuild is very straight forward. Vintage Double Hose is your friend for parts.

 

[RyanNM]

I talked to my tech and he explained it more accurately this time. My mk5 is a model with the piston without the shoulder, and the replacement piston that SP offered hasn't been available for 12 years- but they did offer a rebuild piston with a shoulder to replace the original "shoulder-less" piston. Does that mean I might be able to find someone w/ a proper replacement piston that has the shoulder in their spare parts drawer and still might be able to have mine repaired? Anyone have the correct replacement piston for sale?
thanks

 

[redacted]

I talked to my tech and he explained it more accurately this time. My mk5 is a model with the piston without the shoulder, and the replacement piston that SP offered hasn't been available for 12 years- but they did offer a rebuild piston with a shoulder to replace the original "shoulder-less" piston. Does that mean I might be able to find someone w/ a proper replacement piston that has the shoulder in their spare parts drawer and still might be able to have mine repaired? Anyone have the correct replacement piston for sale?
thanks

The piston with the shoulder is a newer model but is not necessary to have a very good and safe MK5. I have about 10 Mk5/7 and I believe only one has the upgraded piston. I believe the upgrade did 2 things. It provided a bit more metal to resist icing. And it kept the piston from sticking in the body when there was a catastrophic failure of the HP seat. Before Scubapro got the material right for these HP seats, such failures were not uncommon (I have experienced one).. But just not a problem with the current HP seats. Also, that upgrade did not change the severity of the immediate effects of the failure. It just made it a bit easier and cheaper to repair.

Next issue may be the turret bolt. They were upgraded from chrome plated brass to stainless. Almost all of mine are still the old bolt although I have a few SS in my spares. I did instal one on my granddaughter's rig. They are available from VDH.

 

[RyanNM]

Thanks, Awap

 

[halocline]

Why do you need a replacement piston? Is yours damaged? The symptom of that would be IP creep due to a scratch or nick on the piston edge. It is not difficult to polish those out with micromesh. If it's severely damaged, then you do need another piston.

But more likely, the "tech" read somewhere in some SP memo that this piston should be replaced with a newer part, and then read in some other SP memo that it's no longer available. Ergo, sell the customer a new SP regulator.

Not exactly expert, independent thinking, is it?