New propane leak after tanks filled

I would not use tools on plastic nuts.. Good way to replace them.

Try tightening the big hand nut with some channel locks. Im pretty strong and for some reason my ACME nuts are tight. Few months ago in the cold weather it was hurting my hands trying to install the tanks. Was getting a small leak and needed channel locks to turn the nut a tiny bit more.

Not sure if weather related, but now the nuts are easy to tighten by hand. Just changed one out 2 nights ago. Was thinking in my head i wonder why it was so tight a few months ago?? I did buy new pigtails but i dont really consider a plastic ACME nut as needing to "break in" and stretch slightly. Was really surprised how tight it was. Older fella in an RV would never get it tight by hand.

I have had the threaded bushing loosen inside the valve outlet on a 20 lb cylinder causing a leak between the acme nut and cylinder valve. I used a piece of 1/2 or 3/4 inch flat bar and a crescent wrench to snug it tight. The following video shows the removal of the bushing at the beginning of the video. I did not remove mine. I only snuged it tight. The seal might not be replaceable as it is not an O-ring.

https://youtu.be/43PfG0gwT-g

Other valves have replaceable O-rings and seals:

O-rings and seals

I would handle it like a tire. Add some detergent to a spray bottle and then spray everything to isolate the leak. And then deal with the leaking component.

Inside the ACME Nut

1) O-Ring that seals the connection between ACME Nut and Propane OPD Valve connection

2) Thermal Bushing where hose enters ACME Nut (melts if temps exceed 240*F which then allows the OPD Springloaded vlave to close stopping all propane flow)
*2 types of the thermal bushing

OLD one that was redesigned because it had high failure rate
NEW one that has better 'collar' around the bushing


This is the OLD one




This is the NEW one




In either case if leak is AT the ACME Nut to OPD.....check for missing O-Ring inside the ACME Nut
If leak s at the 'bushing'---new pigtails

Boon Docker wrote:

haste maker wrote:
Put some Vaseline on the rubber o-rings

Never use petroleum based products on rubber, use silicone based products.

This - aka plumbers valve grease Not water, petroleum soluable or flammable.

There's a rubber grommet inside the port on the valve with a brass center ring. Twice I've had inexperienced refillers damage them. One was damaged to the point that it fell out while unscrewing the refill nozzle from the cylinder, and the other had the brass center ring damaged enough that a POL or ACME connector could not seat properly. I was able to salvage the cylinders using parts from scrapped cylinders that had the same brand valves.

haste maker wrote:
Put some Vaseline on the rubber o-rings

Never use petroleum based products on rubber, use silicone based products.

If you are sure they are on correct, square and fully seated then I would assume you need new pigtails. Seems odd that both failed together like this. Do inspect for damage or have someone double check the connection for you before spending money.

Some pigtails don't last very long, check with soapy water and replace them if they are leaking.