Complete ScubaPro MK2/R190/R380 Repair Steps/Parts List...

[uranium]

Hey guys, really enjoyed this thread and used quite a bit of the advice here to diy this old Mk2 which I found locally, and am hoping to overhaul and use it for dives.

Initially, I could not remove the yoke retainer due to a rubber piece in between the yoke and the first stage body which didn't give enough thread where the tools could hold. So I cut the rubber piece after all else failed and that gave sufficient room and I was able to successfully remove the yoke retainer.

IMG_20180313_172351

• uranium
• Mar 14, 2018

On this, is the rubber piece at all required for the functioning of the Mk2 or will it work just fine without this rubber piece?

IMG_20180313_172408

• uranium
• Mar 14, 2018

IMG_20180313_172415

• uranium
• Mar 14, 2018

IMG_20180313_165637

• uranium
• Mar 14, 2018

The components and the first stage, have big issues with the chrome plating, and it has almost entirely come off in some areas. Even the piston has some chrome coming off, as you can see in the photos. Do these actually affect the proper functioning of the first stage? I have done a ultrasonic cleaning of all components, and replaced the orings.

Also, from a diy standpoint, is it possible to ultrasonic clean and reuse the sintered filter? It seems to clean up the longer I put it inside the cleaner, since it is metal, and im guessing it would continue to function just as well.

I noticed a rubber piece on top of the piston. Is this also required as I did not see it in the schematic for the mk2.

Any advice would be greatly appreciated. Would love to make this first stage work again underwater! Thanks in advanced!

 

[Couv]

Hi Uranium, I see this is your first post. Welcome to ScubaBoard.

It's hard to tell from just pictures, but I don't think I could advise using this reg on a dive other than perhaps in a pool. Re-purpose it to inflate car tires and kids toys. Sorry, I know that's not what you want to hear, but from where I'm sitting that's the best advice I can give. If you're going to pursue rebuilding this death trap here is a little more info.....but be warned. If you dive this regulator, you'll die.

The problem with rebuilding a regulator with the amount of corrosion apparent in your photos is that even if you put new seals into it, you may have a leak due to the imperfect sealing surfaces. Yes, the chrome serves a purpose on the inside as well as the outside, but with very fine sandpaper (600 grit and finer as found in a micro mesh kit) you'll be able to restore the sealing surfaces sans chrome. However, this is the type of project you'll have to open up at least every six months to re-clean the corrosion out of the body.

So I cut the rubber piece after all else failed and that gave sufficient room and I was able to successfully remove the yoke retainer.

The piece you cut is a spacer and while not necessary, clean off the rough bits and reuse it.

Also, from a diy standpoint, is it possible to ultrasonic clean and reuse the sintered filter? It seems to clean up the longer I put it inside the cleaner, since it is metal, and im guessing it would continue to function just as well.

Usually you can clean a sintered filter in an US cleaner, but your's shows corrosion-i.e. loss of material and the US cleaner will accelerate that loss. If loose particles make their way into the inside of the first stage who knows what damage they'll do? Replace the filter, even a flat filter would be much better than the one you have.

I noticed a rubber piece on top of the piston. Is this also required as I did not see it in the schematic for the mk2.

It's hard to tell what this might be. Most likely it was a sleeve that was installed in the wrong position. Some MK2s had a sleeve that went between the spring and body. At any rate, it will affect the IP, so you'll probably have to add shims to compensate for the removal of the sleeve.

Any advice would be greatly appreciated. Would love to make this first stage work again underwater! Thanks in advanced!

The o-ring sizes are -022 for the piston head and -008 for the piston stem. You can get a parts kit from Store | Vintage Double Hose

 

[herman]

You will also need to polish the face of the yoke nut, otherwise it will likely leak. Polish it with fine sandpaper until it's smooth, even if it means removing all the chrome (likely looking at it)

 

[uranium]

Hi guys, thanks for your replies and advice. I was just looking at this from a overhauling point of view as an interest. It is alright with me if I can only use it in the pool. But if i could rechrome or replace parts so this set can work in the sea, that would be good too, as an exploration and learning thing. Or I could just replace the yoke retainer with a new one, or re-chrome this current one, and that would largely solve any sealing issues.

I can replace the sintered filter. In such a case, what other issues would there be?

 

[herman]

There is no need to replace or rechrome the yoke retainer as long as the chrome inside it is not flaking off, just polish off the end until it's smooth....which will likely mean no chrome remaining. It will work fine, the only issue is it will be a little more prone to corrosion. Just keep it rinsed off and that will not be a problem. If the inside of the end cap is still good, I would not be afraid to dive it. The outside is not really important from an operational standpoint

 

[uranium]

the inside of the end cap looks fine actually. ultrasonic cleaned it and it's nice and clean now.

would you dive this set though knowing what I have shared. I rinse and wash my regulators quite extensively after every dive trip. but there is extensive loss of chrome mostly on the exterior surfaces of the regulator. It seems like the piston sealing surfaces is largely ok. The yoke retainer though, is in a bad state. and the yoke itself is almost entirely brass imo.

you can see a bit of the inside of the end cap in the attached image.

 

[herman]

Most likely yes. The outside of the reg while ugly had nothing at all to do with how it functions and will most likely concern anyone diving around you but as long as the chrome inside the reg and the mating surface of the piston is good, there is no reason it will not function properly.

 

[axxel57]

You will also need to polish the face of the yoke nut, otherwise it will likely leak. Polish it with fine sandpaper until it's smooth, even if it means removing all the chrome (likely looking at it)

Herman, have you ever experienced that a yoke nut is leaking because of chrome flakes or are you guessing?

I have never ever seen a yoke nut sealing area with chrome flakes leaking.

If there is a leak I always found a damage on the gland,yoke or at the tank valve the culprit.

I wish the majority of MK2s I have to service every year would be in such a reasonable shape like the one on the photo....

Right, there is some chrome missing so it doesn't look very nice, but US cleaning and a Dremel with a brass Wheel and a cup brush will take all loose chrome away which might come off otherwise sooner or later.

Most important is the cleaning of the areas where the piston o-rings are moving where usually the rests of the piston o-rings are sticking.

With a wheel brush and isopropyl alcohol and finally a polish pad it is at least no problem to clean the area in the cap.

The rests of the disintegrated dynamic pistom stem o-ring in the MK2 body I clean with coton earcleaners and alcohol.

If lubricated with Cristo Lub 111 or something similar instead of normal Silicone you can use that 1st for long time again, even if the chrome is missing completely on those areas.

Since the the parts with the missing chrome will more easier attract mineral residues of water or humidity, another service might be earlier necessary than for one whose chroming is intact.

Most of the MK2 I'm servicing are from the late nineties and early 2000, they are used almost every day in the year ever since.

They work fine after a service which I see when I do the Flow Bench Tests, sometimes I have to change the main spring, repair the orifice or change the yoke for cosmetic reasons, but these MK2 are built for the real world, extremely strong and long lasting fleet regs.

From what I see on the photos, IMO after a proper service and check I have no idea what possibly could be a problem to use it for what it is made.....

 

[herman]

@axxel57 Look at the 3rd photo. Most of the chrome is missing and there appears to be significant scratches on the yoke nut mating surface. It will most likely leak a small stream of bubbles and should be polished smoothed to prevent it. This practice is common at a local service center that does a lot of regs.

 

[axxel57]

Herman, you are right,that yoke nut gland needs treatment.
I might have misunderstood you.
I thought you mean that the missing chrome alone could cause the leak, which I have never seen.
This yoke nut on the photo has been damaged by using an unappropiate tool, looks liike it slipped, slightly damaging the gland....