Stuck MK10 Piston cap (Scubapro)

[Manow]

My Scuba tools order arrived, and I set out to strip my MK10. The Yoke came off perfect. No issues. The piston cap wasn't as smooth. In fact, I can't seem to even move it. I tried the wrench on my MK5 just to make sure I was turning the wrench the correct direction. The MK5 opened up without any issue, but I didn't take it down. Too bad I can't take the little yoke off the MK5, as my 3/8" drive extension won't fit through the little yoke hole. Back to the MK10. I'm really just looking at the MK10 right now. So, any suggestions on how to loosen up the MK10 Piston cap? I put the reg (MK10) in the freezer, and I'm off to the gym. I think (hope) a little cold time might loosen it up? Any suggestions? Yes, I know a vise would probably help, but I'm at the base of the Tota Bora Mountains (Afghan side) and I just didn't pack a vise for this trip. Silly me. I do have hot & cold water, some soap, a freezer, a scubapro multi wrench, etc. Thanks in advance.

 

[Zung]

You're on the right track. Next, soak it in hot water for at least half an hour, then, back to the freezer. Repeat a couple of times, go hiking and enjoy the view in between, try again.

If you use the boot method for holding the reg, may sure you get the angle right: leave the yoke on and use it as a lever against the carpet/ground to help with your foot. Don't try too hard or you'll break something, most likely the wrench; if it doesn't come off, back to soaking and freezing.

 

[DA Aquamaster]

I would not use the boot method with the yoke as a proper first stage wrench screwed all the way into a high pressure port is more effective and a lot safer.

Generally speaking, if a padded vice is not available the boot method works pretty well. Just keep the wrench fairly parallel to the carpeted surface you are standing on.

If you have access to an ultrasonic cleaner that will help. If not, soaking in. 50/50 mixture of water and white vinegar will help loosen any salt deposits.

There is nothing wrong with the hot water/freezer thing, but it is only partially working the problem which is salt and or corrosion rather than it just being too tight.

Once you get it off, be sure to thoroughly clean the threads (the 50/50 water / white vinegar mixture is ideal. When reassembling it, be aware the chrome has most likely be compromised on the threads and further corrosion is more likely, so lubricate the threads with christolube or silicone grease to provide some additional protection.

 

[Couv]

After the entire reg is cold soaked, use the hot/cold differential method. Pour boiling water only over the frozen cap then try the boot/wrench combination to free it up. If no joy, back into the freezer.

 

[redacted]

Also, to maximize the effects of the hot and cold treatments; when you remove the Mk10 from the freezer (or ice water), dip just the turret end in hot water up to the cap for a minute or so to get the maximum temperature difference between the body and the cap. Then go ahead and lower it the rest of the way into hot water to, hopefully gets some water penetration into the threads between the 2 parts. If may take a few cycles of this treatment to loosen up and maybe dissolve whatever has that locked up. The key is patients and not too much force. Or you could try to find someone in your area with an ultrasonic cleaner.

 

[Manow]

I got it open. Finally. Remember that old saying: “it took two men and a boy to lift that thing?” Today I went into the Afghan Woodshop, and they have a vise! I locked the first stage tool in the vice, and I dropped my full 200 pounds on the wrench. Nothing. Then, a big Afghan kid saw what I was doing, and he put his hands on top of mine. And we both dropped on it. It broke free, and we fell to the floor. I gave him a high-5. The kid has no idea what the first stage is. I was sure that the aluminum multi tool or the aluminum 1st stage tool would snap. Nope. Both are pretty strong, and I give Scubatools.com an A+ for strength. I think the leverage would be better if the tool was a little longer, but then it wouldn’t be small & lite for travel. The inside of the reg. is really clean, and the threads aren’t too bad. I used a small safety pin, and the High pressure seat popped right out. No need for that expensive HP Seat removing tool. Tomorrow I’m going to the Afghan garage to seek out an Allen wrench to remove the swivel cap. I had a heck of time trying to get the little tiny o-ring out (the one in the reg. body; the one that the piston passes through). I was looking at the High pressure seat. It has a very clear cup type marking on the business side, but on the opposite side it looks un-marked. I’m thinking that I should hang on to it, as maybe I can just flip it over and use it again (in the event I’m unable to locate a service kit in the future?) I have everything soaking in vinegar-water-soap right now. I’ve been doing this off & on. It’s a real pretty piece of gear, and looking at the individual parts really makes a mental connection to everything I’ve been reading. So far I’m up to 6 o-rings, not counting what I may find inside the swivel cap. My plan is get the swivel cap off, get everything clean, and then (for practice) basically re-assemble the reg. using the old parts. I’ll use some cheap silicon lube. I’m relatively confident that I’ll be able to pick up a re-build kit during my up-coming Asian holiday. Thanks again to the usual suspects. Your feedback & tips are appreciated.

 

[Zung]

Congrats!
2 remarks:

• Soap and vinegar neutralize each other
• Careful with that small o-ring (2-010) inside the body: it's not easy to get it in & out, and I wouldn't do that for fun or practice. Btw, it needs to be a Durometer/Shore A 90 , the harder sort

 

[axxel57]

Quite some help is also the three feet long metal or plastic tube you use as extension for your hook spanner or Allen key to have a bigger lever advantage. No need for boys help and you got much more 'feeling' for the force you're applying.

 

[redacted]

Applying lots of force to a regulator is unnecessary and may well produce damage before the desired result. It is just a matter of time.

When they do not disassemble as easily as they should, it is very unlikely that the connection was over torqued to begin with. The cause is almost always salt and oxidation in the threads of the connection. Salt and oxidation can usually be dealt with without resorting to excessive and possibly damaging excess force. OTOH, as long as you are dealing with older regs that are fairly cheap and parts are hard to come by, them your failures can just be added to the spare parts bin - like a regulator junk yard.

An acid bath will also attack the chrome, just much more slowly than the oxides. The trick is to spend as little time in the acid bath as is necessary to loosen the oxides and not cause unnecessary damage to the good finish.

Good Luck.

 

[axxel57]

Unfortunately often enough the acid will not penetrate the threads, not even with the ultrasound cleaner, before it is damaging the chrome parts. I tried it lots of times also one short exposure time after another, but also that didn't work at all. Best results I have ( odd enough?) with liquid silicone. If I was able to move the parts just very slightly it seems that the silicone can penetrate threads better than the acid and is at the same time ''oiling' them. That works especially good with plastic threads f.e. when a diaphragm cover of the 2nds is hard to open. I put the silicone liquid on the joint between the cover and the case and tap? with a plastic hammer carefully against it. Often that helps to be able to open the cover without excessive force.
Concerning the tubes: If a regulator hasn't been serviced for long time and is in bad condition I found that having a way to apply force in a more controlled manner is not a bad thing when nothing else softer works.
Thanks for reading......