1st stage keeps getting stuck on my tank!

[dmoore19]

I had problems similar to that on my reg. As Wookie suggested it turned out to be some stuff on the threads of the yoke screw. I took it out, used a tooth brush to clean the threads and put it back together. I didn't have any more problems.

 

[underH2Oman]

I would think it sounds like a bad o-ring in the tank. If air gets behind the o-ring and seals the reg in place, but then the air can not get out from behind it will hold the reg in place firmly.
Try changing the tank o-ring.

 

[Akimbo]

... As Wookie suggested it turned out to be some stuff on the threads of the yoke screw. I took it out, used a tooth brush to clean the threads and put it back together...

A related compounding factor is that Chrome plating can sometimes peal, creating tiny barbs that act in one direction. Your suggested cleaning will take care of them too. Don’t forget to clean the internal threads as well as the external. Friction increases as the Chrome deteriorates and Copper Oxide forms.

Sometimes it is hard to hear when the purging actually stops due to ambient boat or beach noise. Just hold it down a few extra seconds. Clean and lube threads if the problem continues. It is a common problem. Most boats keep a pair of channel-lock pliers handy for this reason.

 

[phlegm]

You are purging the system before trying to take the reg off, right?

yeah I'm fully purging all air.

 

[mockney]

Nice post, I have been experiencing exactly the same issues for my last few dives, been a nightmare trying to remove my first stage form the Tank.

But some excellent advice given so I will take that on-board, I think my problem is I have been slightly paranoid and screwed my first stage a tight as I could, that has compounded the problem.

Just thought I should reply so you know your not on your own with this problem

 

[BRT]

Lube the threads with silicone, tighten the clamp pretty tight to avoid the o-ring extruding out, purge ALL air, hold the knob and turn the regulator a little to break it loose. You have a lot more leverage on the reg than on the knob.

 

[phlegm]

thanks heaps for all the suggestions. faulty o ring is a distinct possibility as the tanks are rentals from the uni dive club, so much used and abused.

I have silicone grease too so I'll give that a crack.

one left field suggestion though from g1138: how does offsetting the reg reduce the chance of it getting stuck? you seem to know what you're talking about I'm just not quite understanding why that would work.

 

[fbk]

how does offsetting the reg reduce the chance of it getting stuck? you seem to know what you're talking about I'm just not quite understanding why that would work.

By giving the yoke and screw room to move together if rotated.. if the yoke is jammed against the valve knob and you turn the screw you'll tighten it further although the screw should not budge once pressurised.

I have had the same and similar problems before and all the advice offered is good. Even completely purged these things can get stuck on so tight that you need tools to undo the screw. If the parts of the 1st stage or tank valve (the ones in contact with the o ring) are burred or damaged, the 1st stage can get jammed on tight. Expansion/contraction of the metal parts can also contribute. Cleaning and lubing the yoke threads will go a long way to preventing it.

 

[g1138]

thanks heaps for all the suggestions. faulty o ring is a distinct possibility as the tanks are rentals from the uni dive club, so much used and abused.

I have silicone grease too so I'll give that a crack.

one left field suggestion though from g1138: how does offsetting the reg reduce the chance of it getting stuck? you seem to know what you're talking about I'm just not quite understanding why that would work.

You can test this. Without turning the tank on, put the reg on, screw the yoke till its finger tight. Standing behind your tank and reg (ie. octo on right), rotate the reg so the octo hose is going clockwise. Keep rotating in full circles and you will see that you're actually tightening the reg even more into the yoke screw, even though you're not touching it.

When the yoke mount is braced against the tank valve (knob side; so opposite of what my picture shows), the reg and yoke screw tend to spin together when you're rotating the reg.
Offsetting the yoke mount off the tank knob prevents the reg from tightening should it rotate against the braced yoke mount in the direction that tightens the whole assembly

The reg has to be braced with the yoke mount off the tank knob side to prevent this.

 

[DaleC]

If all that fails look at the back of the tank valve, where the screw from the yoke sits in the divot. I have this problem with none of my tanks save one. On that tank the yoke always gets stuck tight. After looking at everything it turns out the screw seizes to the metal on that particular valve (?) so I put a little silicone grease there.