How Do I Reverse the Seat in 1st Stage Calypso Regulator?

[JamesBon92007]

I've read a lot about servicing the various Aqua Lung regulators and thanks to the posts here and the links to the service manuals I have successfully serviced several regulators including first and second stages plus an old US Divers SPG, and old US Divers depth gauge, a couple of BCs, and an old US Divers K valve. But, I'm not sure just how to remove the seat in the first stage. On one there are two small holes (not sure of the model but it looks like a Deepstar) under the valve seat. Am I supposed to push it up and out from the bottom? It works fine the way it is so I figured I'd better leave well enough alone, for the moment. The other is a Calypso J and I forgot what that one looked like but I would appreciate suggestions for it too! One of the manuals indicated that the seat is reversable and from what I've read here it should last a long time if I reverse it each time I service the regulator. Both regulators had a slow, steady trail of bubbles coming from the vent holes in the first stage and now both seem to be AOK. Now if I could just find a great deal on a doublehose that can be restored.

Thanks!

 

[herman]

On most all of the flow-by piston type regs there is a small hole in the piston under the HP seat. If you point the HP seat at a light and look up the piston stem you usually can see the hole. You push the seat out with a small drill bit- using the dull end of the bit. Unless you have IP problems- creep- I would not rotate it. You may have problems finding a replacement so why use the other side if you don't need to, the flip is a one shot deal. Do not do it on each rebuild.....and resist the urge to rebuild it if it does not need it. The leaks were from either dirt in the piston chamber or bad Orings. Dissamble, clean, replace the Orings and relube but I would not swap the HP seat unless it's necessary which is unlikely. Same goes for the Calypso.
Good luck on the DH, those are getting harder to find cheap.

 

[JamesBon92007]

Thanks. Both of the first stage seats on the AquaLungs had slight depressions visible but I'll take your advice and not reverse them until needed. There was *some* corrosion inside, here and there, but nothing really bad. The Sherwood that I serviced looked brand new inside--it has a positive air pressure something-or-other (it's *supposed* to leak some little bubbles) and it seems to work as advertised.

When you say "resist the urge to rebuild it" do you mean that annual service, as promoted by dive shops, is probably not necessary?

 

[herman]

"Probably not necessary" is an understatement. Those regs will easily go 4, 5 or more years and work perfectly if you take care of them - don't get salt water inside of them, rinse them well and keep them out of the sun and heat. I spent a good bit of time restoring old regs and for grinns I usually test them before taking a wrench to them, most of them still worked after who knows how many years of laying around. The ones that did not usually showed signs of poor care, green crud inside and out.
The old Sherwoods are not glamorous but they do work forever. It would most likely be my reg of choice if I needed a reg to last for many years without service or parts.
Most of those old regs use the same size HP seat. Keep an eye on ebay for Sherwood kits, they have 90% of what you need for the old flow-by piston regs and most of the time go for less than $4.

 

[duckbill]

The o-rings are usually the first to go. Buna-N will last quite a while as long as you don't run enriched oxygen, but Viton will last even longer. If you want to go the extra mile, pay the extra for Viton o-rings, but they aren't necessary.

 

[JamesBon92007]

Are these O rings from a dive shop or another source? I think the only O ring I ever got from a dive shop was for a tank, and I'm kinda surprised how rarely I've had to replace one of those.

My old US Divers regulators have, quite possibly, never been serviced before and they both still worked, other than a small amount of bubbles coming from the first stage. I have not yet looked at the valve seats in the second stage because the hex that is next to the hose is either cast onto the housing or is simply very, very tight. According to a service manual it should come apart there but I'm afraid of damaging breaking something. The pressure on the Calypso J is only about 128 psi--seems kinda low. Shouldn't it be more like 135-145? I've read about adding shims to increase the air pressure--are these added in such a way as to increase the spring tension? Are they simply stainless steel washers or discs?

 

[herman]

Usually another source, either an on line Oring dealer, plenty of them or McMaster Carr. You will need to know the size and durometer to order, no scuba part numbers.

That nut contains the LP hard seat (or orifce) and it should come loose. Try soaking it in hot (as hot as it will come out of the tap) for several minutes until it's almost too hot to hold with the cover and diaphram removed. Lay the second stage down on the cover mating surface and while holding one hand on the reg body, press down on the wrench with the other hand. Keep the wrench close to the table as possible, all you are trying to do is to get a slight turn at first. Once it breaks loose then unscrew it all the way. If at all possible use a box end wrench or a 6 point socket for maximum wrench bite on the surface, this is no place for an adjustable wrench. It should come loose, it may need a good bump with your hand. If a good bump does not loosen it then odds are it is corroded shut. If it's still stuck, soak it for several minutes in a 50/50 mix of warm water and white vinegar solution and try again.

Per the manual, 128 is perfect at a tank pressure of 2000psi, it is not uncommon for older regs to have lower IPs, I have seen 110 on several regs. If you want to raise it, you just install a small shim under the spring. SS will do or a hard plastic can also be used. The shim is very thin, nothing like a standard washer.

 

[captain]

You should be able to blow the seat out with compressed air if there is an equalizing hole behind the seat. I do it on my Scubapro MkV seat.

 

[Paladin]

I just bought 250 Viton 90 Durameter O-rings for my Aquarius regulators from McMaster Carr for 29 bucks, including shipping. The Aqua Lung manual tells what size to get for your Calypso J. Look at the part number. The last three digits is the size of the O-ring. For example, Part number 7, 8200-08 is a size 008 O-ring.

As for the HP seat, if it ain't broke, don't fix it. A slight indentation in the seat is normal. I have a 40 year-old Aquarius here that is still using its original seat and it has never been flipped. So, if yours isn't leaking, then leave it alone.

 

[JamesBon92007]

OK, thanks for all the great tips! The nut that reveals the LP seat definately looks like a 6-point wrench situation. I just wanted to hear it from someone else before going any further, just in case there was more than one kind made and the manual didn't tell me. Not that there is another way to get to the seat.... The LP seat works fine but I was hoping to inspect it and possibly clean it so I guess that is now going to depend upon how hard it is to get to. I got the regulator(s) in the 70's and the LP seat has not been cleaned since so a couple more decades probably won't hurt.