Hatsan AT-P2 developed a leak

[sactargetshooter]

A fill to 185 bars went to zero over a day. Definitely a leak that needs to be fixed. I looked up instructions to fix similar leaks on the AT44 platform and thought, hey, I can do this.

Well, the AT-P2 cylinder is not exactly the same as that of the AT44 platform. Here is the process that I used.

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• Be sure to use lube that is engineered for high pressure (3000 PSI) applications!
• Use the bleeding tool to equalize air pressure, I kept the tool on as a dust cover during the process
• Unscrew the cap on the manometer and remove the dust cover on the fill port
• Use a long (8" should be fine) steel rod across the fill port for leverage
• You may have better luck with a soft (rubber strap) pipe wrench. I had to use a real pipe wrench to hold on to the cylinder. That marred the finish
• Unscrew the fill port assembly from the cylinder, you may need a bit of torque to do this
• There should be two O-rings on the fill port assembly, not one. Mine was missing the one closer to the manometer
• Use a pair of snap-ring pliers to remove the snap ring on the inside of the fill port assembly. This part is different from the AT44 platform.
• The check valve should slide out. This is also different from the AT44 platform where the check valve is spring loaded.
• Inspect and if necessary replace the O-ring on the check valve. Mine looked fine. I just cleaned, lubed and reused it.
• I also lubed the side of the check valve before putting it back into the assembly.
• I lubed the two O-ring and thread of the check valve assembly before reassembling.
• Hand tighten until snug, then use a pipe wrench and a rod across the fill port to tighten up the fill port assembly
• That's it! Unscrew the bleeding device, and fill the cylinder without inserting it into the gun.
• Pressurize and monitor for any leaks. I have read that the manometer itself can also leak, so just fixing the check valve may not resolve the problem.

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Hope this is helpful to someone!