DIY reg servicing

[Hoyden]

I have both books - if I could only have one of them and didn't have access to a shop bench, I'd want the Harlow book. There is a lot of information on work-arounds (how to get by without the "right" tools and/or how to make your own tools) in it. Having said that, I personally got more out of the Wolfinger book - I really like to understand what I am doing as opposed to just following directions.

JMO,

Jackie

 

[Packhorse]

Thanks for all the feed back.
I got some service kits today.
The MK20 repair kit # 10750041 has 2 large white rings with a cut thru them.These are the shape of an Oring and 6 small plastic rings with a lip on the top outer edge and another lip on the bottom inner edge. 2 are grey and 4 are black.
These parts are not on the exploded diagram that I have and I saw nothing similar when I pulled the reg down. Anyone know what they are for?
The MK10 kit # 10500041 has 3 HP seats. They are marked +,-1,-11. There is no mention of diffrent HP seats in the service manuel. I assume these are used to adjust IP pressure?
I have also got an IP pressure gauge and my MK20 was running 12 bar. I removed all the shims (2 clear 1 black) and the pressure is now 10bar. Is this OK or should I look at a new spring. Before I removed the shims my D350 would constantly "burp" slowly and wouldnt stop when adjusted. It seems fine now at 10 bar (145psi)

 

[redacted]

Thanks for all the feed back.
I got some service kits today.
The MK20 repair kit # 10750041 has 2 large white rings with a cut thru them.These are the shape of an Oring and 6 small plastic rings with a lip on the top outer edge and another lip on the bottom inner edge. 2 are grey and 4 are black.
These parts are not on the exploded diagram that I have and I saw nothing similar when I pulled the reg down. Anyone know what they are for?
The MK10 kit # 10500041 has 3 HP seats. They are marked +,-1,-11. There is no mention of diffrent HP seats in the service manuel. I assume these are used to adjust IP pressure?
I have also got an IP pressure gauge and my MK20 was running 12 bar. I removed all the shims (2 clear 1 black) and the pressure is now 10bar. Is this OK or should I look at a new spring. Before I removed the shims my D350 would constantly "burp" slowly and wouldnt stop when adjusted. It seems fine now at 10 bar (145psi)

Different Mk20 pistons (I believe there are 3) use different o-ring configurations. Older version used an o-ring and a backup ring (the large white splitring). The newest composite piston uses 2 o-rings in seperate groves, one in the piston head and a second "wiper" ring sandwiched between the piston head and the black cold water bushing. Generally speaking, you want to reinstall whatever you remove. That kit services all versions of the Mk20 amd the Mk25 so you will have plenty of leftovers. I have a collection of the grey and black washers that I don't use. Schematics for the Al and the Ti versions show washers in addition to o-rings on the HP & LP port plugs. I believe they are used there and for hose connections with those versions. I'm not sure whether it is trim or functional.

Mk 10 did use a "hockey puck" seat that had some anoying whistling problems. The new "cave cone" seats deal with that problem and come in 3 slightly different heights so the tech can adjust the IP by just changing the seat rather than going thru all the work necessary to change IP adjusting washers. I still just use the IP adjusting washers and can usually get at least 2 of those seats to work in any regulator. I guess that makes up for losing the capability of renewing the seat by flipping it to get a new face.

When springs wear out I thought they should weaken rather than strengthen. 12 bar (about 177psi) is high enough to comprimise LP seals. 10 bar (148psi) is still high but probably workable until it starts to creap. Before you do anything, I'd first confirm that the IP gauge is giving accurate readings. With no washers, I'd have expected an IP in the 8 to 9 bar range. Also, check the thickness and number of washers under the HP seat retainer. You could eliminate the washer in that location to bring the IP down a bit more. I usually set mine fairly low at 125 -130 psi (8.5 bar) which still provides adequate performance.

 

[scarefaceDM]

A few other helpfull tools I use are, dental picks. Ask you local dentist if they have some old ones( CLEANED ) hanging around. or find a medical supplier, various tweezers, locking pliers, a vis with SOFT RUBBER ends, clamps to hold any parts. A Ligthed magnifing glass lamp. Plus a soft pad of sorts to work on. Varouis soft bristle brushes to clean parts and a few soaking bins aswell......Also surgical rubber gloves, keeps the grease from your finger off the reg parts. And a nice BEER fridge just to keep you hydrated.

Have fun

 

[Packhorse]

My MK20 has the 2 piston head Orings. But has a metal piston not composite. I checked the IP on 2 MK25's and they were 140 PSI so I guess the gauge is fairly accurate.

I picked up some picks yesterday, and I already have the beer fridge tool so Im half way there.

Any ideas where I can find the specs on various Orings? It would be nice to be able to just buy the dynamic orings for the yearly service and do the HP seats every second year. Since I have a few regs and they may only do 30 dives each per year I dont really see the point in replacing seats if they still work fine.

 

[redacted]

Any ideas where I can find the specs on various Orings? It would be nice to be able to just buy the dynamic orings for the yearly service and do the HP seats every second year. Since I have a few regs and they may only do 30 dives each per year I dont really see the point in replacing seats if they still work fine.

I think I have worked out the std o-ring equivilents for most of the Scubapro o-rings. There are a number of choices in materials but it seems that EPDM is most popular right now based on performance and price. Nitrile (BUNA-N) will still do the job fine for air regs but there life expectancy is shortened by high O2 environments. Viton is (was) another popular material but tends to be higher priced. I started out using Viton but have been seitching to EPDM as I run low. I've also used urathane For the HP piston shaft as that seemed to be what Scubapro was using about 10 years ago. For hardness, I use duro 70 or 75 for all applications except the HP piston o-ring where I use duro 90. The softer o-rings will extrude in that application. The HP piston o-ring in both the Mk20 and the Mk10 is a 2-010. The piston LP o-ring is a 2-017 for the Mk10 and a 2-022 for the Mk20. The turret swivel o-ring for both is a 2-017. The retainer for the HP seat on the Mk10 is a 2-013 or you can use the new flat ring provided in the service kit. The Mk10 seat retainer o-ring is a 2-015. The Mk10 anbient chamber seals to the body with a 2-117. The yoke nut or DIN retainer on the Mk10 & Mk20 is a 2-011. The Mk20 seat o-ring is also 2-011. Hose and port plug o-rings are all standard. I think that an automatic annual renewal of o-rings is not necessary. I clean my regs whenever they show a need but usually don't automatically change o-rings. I expect dynamic o-rings to last 2 years or more and static o-ring to last 5 or more years. I've got some o-rings that are 10 to 20 years old and still sealing. I would expect at least 2 years from an HP seat and I have some that have been doing the job for 5 years or more. When I replace doubled o-rings like on the Mk20 piston or the poppet stem on the scubapr balanced poppets, I use a new o-ring in the inner position that provides the LP seal, but I usually put a used servicable o-ring in the wiper position. It probably does not matter too much with the Mk20 piston, but the poppet on the S600/G250/BA takes an odd sized metric o-ring that can be hard to find. If you are going to order o-ring, throw in some 2-003 for the spool on your SPG.

Let me know if I left anything out.

____________
And eventually you get old enough where neither of them are important any more.

 

[divinginn]

great thread for us scubapro junkies.

 

[deepblueme]

Please do your self a favor and DO NOT USE dental picks......
ONLY use brass picks as a stainless metal pick can and will scratch the chrome in an O-ring groove (seen it done many many times) in the case of the piston shaft O-ring it can cause bubbles to come out the Amb.ports.

As to the reusing the cave hp seat, if you remove the hp seat/cap away from the piston in the mk10/mk5 style (sharp edge piston), and then replace. You can cause IP creep due to the knife edge not meeting up with the old groove.

 

[Luis H]

I think I have worked out the std o-ring equivilents for most of the Scubapro o-rings. There are a number of choices in materials but it seems that EPDM is most popular right now based on performance and price. Nitrile (BUNA-N) will still do the job fine for air regs but there life expectancy is shortened by high O2 environments. Viton is (was) another popular material but tends to be higher priced. I started out using Viton but have been seitching to EPDM as I run low. I've also used urathane For the HP piston shaft as that seemed to be what Scubapro was using about 10 years ago. For hardness, I use duro 70 or 75 for all applications except the HP piston o-ring where I use duro 90. The softer o-rings will extrude in that application. The HP piston o-ring in both the Mk20 and the Mk10 is a 2-010. The piston LP o-ring is a 2-017 for the Mk10 and a 2-022 for the Mk20. The turret swivel o-ring for both is a 2-017. The retainer for the HP seat on the Mk10 is a 2-013 or you can use the new flat ring provided in the service kit. The Mk10 seat retainer o-ring is a 2-015. The Mk10 anbient chamber seals to the body with a 2-117. The yoke nut or DIN retainer on the Mk10 & Mk20 is a 2-011. The Mk20 seat o-ring is also 2-011. Hose and port plug o-rings are all standard. I think that an automatic annual renewal of o-rings is not necessary. I clean my regs whenever they show a need but usually don't automatically change o-rings. I expect dynamic o-rings to last 2 years or more and static o-ring to last 5 or more years. I've got some o-rings that are 10 to 20 years old and still sealing. I would expect at least 2 years from an HP seat and I have some that have been doing the job for 5 years or more. When I replace doubled o-rings like on the Mk20 piston or the poppet stem on the scubapr balanced poppets, I use a new o-ring in the inner position that provides the LP seal, but I usually put a used servicable o-ring in the wiper position. It probably does not matter too much with the Mk20 piston, but the poppet on the S600/G250/BA takes an odd sized metric o-ring that can be hard to find. If you are going to order o-ring, throw in some 2-003 for the spool on your SPG.

Let me know if I left anything out.

____________
And eventually you get old enough where neither of them are important any more.

awap

Do you have the equivalent standard O-ring numbers for the Mk-5?

Thanks

 

[oxyhacker]

We have a massive downloadable regulator O-ring database by Scubaboard regular Brian Cooper on our website, at:

http://www.airspeedpress.com/OringDBconsent.html

However if you need just the Mk5,

Mk V 1st
swivel 012
piston HP 010
piston LP 022
yoke retainer 015
HP seat 013
seat retainer 015

109 (metal adjustable) 2nd
hose swivel end old style 010
hose swivel end Superflow 1x7 metric
orifice 010
balance chamber (balanced adjustable and later only) 1x1.8 metric

Do you have the equivalent standard O-ring numbers for the Mk-5?