Walther LP400 air cylinder problem

[javaduke]

I'm having a strange problem with one of my LP400 air cylinders. It won't charge when I screw it onto the adapter and the air tank. My other cylinder works just fine with the same tank and the same adapter. When I screw the adapter onto the cylinder, I hear the air coming out, so it seems like the adapter is able to open the cylinder piston.
Has anyone had the same problem? Is there any easy fix or should I send the cylinder for repair?

[Gwhite]

The O-ring in the cylinder that seals against the neck of the fill adapter has probably gotten damaged, worn out, or dirty. As a start, I'd examine it carefully to see if anything obvious is going on. Because it's down in a hole, it's not nearly as easy to replace as some. You can try swabbing it clean (make sure you don't leave any fibers behind), and then apply a thin coating of silicone grease (Superlube is a good option & is available lots of places). You can also try applying a thin coating on the pin on the fill adapter. Your working cylinder will last longer as a result.

Depending on the age of the cylinder, you may not be able to get it repaired. Also, the cost of repair will often come close to the cost of a new cylinder.

[javaduke]

Yes, I do use the lube on all my cylinders and adapters. The O ring looks normal. I guess I'll just need to get another cylinder, this one expires in January 2021 anyway...