Removing the diaphragm from a second stage

Please register or login

Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

Benefits of registering include

  • Ability to post and comment on topics and discussions.
  • A Free photo gallery to share your dive photos with the world.
  • You can make this box go away

Joining is quick and easy. Log in or Register now!

d^2b

Worse diving through photography
ScubaBoard Supporter
Messages
527
Reaction score
347
Location
Canada
# of dives
500 - 999
I was following the regulator checklist, and kindof got stuck at step 11. The cover (and a thin metal washer between the cover and diaphram come of easy enough, but the diaphram doesn't come out easily. It feels like there is a little rubber ring around the edge of the diaphram, I believe it is attached. Am I supposed to disassemble more, or pull harder? Or is every reg different? This is a lesser-known brand sold by Divemar in Canada.

 
They get stuck a little sometimes. Pull gently with increasing force. They are pretty tough. If a bit more force doesn`t work soak it in a 25% solution of vinegar for 10 minutes or so.
 
A lot of people do not recommend using vinegar on rubber or plastic parts. If you choose to try it, you are forewarned if things start to dissolve or turn into sticky goo on you.

The thick edge is probably the sealing part of the diaphragm and is all one molded piece. You can try gently pulling toward the center and work your way around until you find a spot that is not stuck and can pull the rest free.

If that doesn't work, you might try to get a plastic pick between the outside edge and the case. Be careful not to tear it. DO NOT use a metal pick that could puncture or tear it.

If that doesn't work, you very well may have to destroy the diaphragm to get it off if it has been like that for years and the rubber is old, hard and fragile. Make sure you can find a replacement first.

Good luck!
 
Hot, soapy water soak.
Plastic dental pick, run it in the gap between the outer edge of the diaphragm and case.
THEN, begin tugging more forcefully. Once any part lifts, take that plastic dental pick and run it around behind the diaphragm rim and it'll pop out.

Yes, that thicker rubber rim on the outer edge is part of the diaphragm. It's attached to the diaphragm. You can see the tiny groove pressed into that rim where the metal thrust washer was slightly off center.
 
I can confirm the soapy water and the o-ring remover from my olympus housing did the trick. There was not any visible gunk behind the diaphram, which is good news, I guess. The original question that got me off on this journey (other than cabin fever) is a little hiss from the octopus. Both second stages have approximately 1.5" cracking pressure, but octopus has a little bubble when flipped the other way up and only the mouthpiece immersed. This amounts to just over a 400 psi loss when the valve is turned off, so I don't know if it's anything to worry about. The octopus is new, so I guess I'll talk to the person that sold it to me if / when the lockdown ends.
 
Yay! for getting the diaphragm apart.

The octopus should definitely not leak like that. But before you take it apart, check the IP to make sure it's not too high (and a first stage problem).

The octo cracking pressure should be at about 1.5

You should be able to adjust the cracking pressure of the primary closer to 1" without it free flowing easily.

By the way, when was the last time everything was serviced? With the diaphragm stuck like that, I'm guessing it's been a while.
 
Yay! for getting the diaphragm apart.

The octopus should definitely not leak like that. But before you take it apart, check the IP to make sure it's not too high (and a first stage problem).

The octo cracking pressure should be at about 1.5

You should be able to adjust the cracking pressure of the primary closer to 1" without it free flowing easily.

By the way, when was the last time everything was serviced? With the diaphragm stuck like that, I'm guessing it's been a while.

The IP is about 120 PSI, which seems a bit low. But I don't have a service manual for this reg.

The octopus is new, with about 8 dives on it. I think the diaphram was not really stuck. It just has a ridge around the edge that fits into a groove around the edge of the second stage (something like an o-ring groove). So it doesn't slide away from the walls like I was expecting.
 
a little hiss from the octopus.
The octopus is new, with about 8 dives on it.
Yes, typically IP is a bit higher 125-145 psi, however low IP will not cause the small freeflow you have detected. The important factor for now is a steady/consistent IP.

Now that you have the diaphragm removed, how about at picture of the inside of the second stage? We may be able to talk you through a slight tweak that will fix the hiss.
 
Yes, typically IP is a bit higher 125-145 psi, however low IP will not cause the small freeflow you have detected. Now that you have the diaphragm removed, how about at picture of the inside of the second stage? We may be able to talk you through a slight tweak that will fix the hiss.
It probably just needs a slight adjustment due to having seated after sitting a while and being used. Depends on where the tech set the cracking pressure when it was serviced.
 
It probably just needs a slight adjustment due to having seated after sitting a while and being used. Depends on where the tech set the cracking pressure when it was serviced.

That's where I was going by quoting the pertinent remarks from his post. However, I don't know what sort of demand valve his second stage has.
 
https://www.shearwater.com/products/peregrine/

Back
Top Bottom