Air Leak hatsan at-44

[wormbobskey]

I have an air leak at the fill port of my at-44. Has anyone ever fixed one of these or is this something that has to be done at the factory level? Not sure if maybe dirt got in the fill port or what. What sitting at computer desk this morning and rifle discarded about 150 bar of air all at once while sitting in its rack. Never noticed any leaks before today. Filled it slowly to 100 bar and could hear it leaking out. Any help is appreciated.

 

[blackdiesel]

Sorry haven't had this particular problem, but a worn o-ring or dirt are pretty much the only culprits I can think of. It's easy to degass Hatsan cylinders and replace the o-rings. Use the degasser that came with the gun, unscrew the part behind the gauge and see if there are worn o-rings. You can get an exploded view from the Hatsan page to see where the o-rings are located. Hatsan USA will give you the size of the o-ring if you have the part no. or you can get it from Hatsan. 

 

[wormbobskey]

No need to degas the air cylinder as the pressure leaked off. Lol. I just wasn't sure how to go about finding out if I could even fix a faulty o-ring there or not. Appreciate the help.

 

[Mrshosted]

Hatsan is very easy to work on. You probably find a bad Oring when you un screw the end. I use a strap wrench to hold the tank. You may find you Oring at Hydrapak 801-973-7325. It will cost about .50 cent to repair

 

[wormbobskey]

I'm a little leery about trying to remove the fill port. Don't have the correct tools to do it properly. I have tools and I'm sure I could get it off, I'm just worried I will end up tearing it up or worse, destroying the end to where I would need to replace the entire air tube. 

 

[wormbobskey]

Can anyone walk me through how to take the fill port check valve out of the fill port housing? HatsanUSA informed me it was probably a faulty oring in the fill port check valve and that was it. No other information, no here's how you can check to find out, nothing. Not even sure why I contacted them in the first place. They did send me a schematic of the rifle with all the parts numbers, but no parts names. Another big thanks to them.

 

[Mrshosted]

Sorry never had that end a part. I'd guess that if you where to degas the tank, It probable would unscrew. Try holding the tank with a strap wrench and twisting off the the end. You could alwise reach out to Rsterne over at the Gatewaytoairguns.com that guy is a Hatsan God. He'd know! 

 

[Mitch1]

I also have a slow leak on my AT-44 air fill port. It takes about 5 days for the air pressure to drop from 200 bar to 140 bar. There is a YouTube video that shows how to repair this type of air leak. Just search for AT-44 air leak and look for: How To Fix An Air Leak On A PCP Air Rifle (Hatsan AT44-10) | Air Armoury. I tried it, but I couldn't break the end fitting loose (I only have a woodworker's vice and strap wrench) so I've decided to live with it for now. Good Luck.

 

[Constantine]

if you bought it new it will usually come with the replacement packing and seals.

 

[CReilly1989]

Guys I need help! I bought a new Hatsan AT44 10 and it had two leaks.. I fixed one before I realized the other place was leaking. 


it’s leaking out of the tiny hole on the end of the pressure gauge. It’s a very small hole in the air cylinder. 


Replacing o rings under the gauge and fill port will solve this issue? 

 

[Mrshosted]

I’m having a hard time understanding where your leak is. Could you post a picture. 

 

[CReilly1989]

This 

this tiny hole right there. Air will slowly leak from it. 

 

[Seth0764]

Are you filling to the correct pressure? You could try replacing the seals but scene it's new I would send it to hatsan for warranty 

 

[CReilly1989]

Yes I am filling to no more then 175 bar actually. It’s sweet spot. It’s Mac fill pressure is 200 bar. I originally thought it was an over fill bleed valve or something but it can’t be. 


as for Warranty.. don’t even get me started. This will probably be my last Hatsan Airgun. I’ve contacted them multiple times. Emails. Phone calls. I only got one answer back, and their solution was to pull it apart and fix it myself. Days and days go back. Can’t get ahold of anyone at Hatsan… A tiny little box shows up at my door step, that contains 3 o rings. I am not 100% sure which o rings they are because I cannot get the damn air cylinder apart. I think I need a vice. 


they didn’t offer to replace, send a new one or anything like that. It’s completely BS. 

 

[Ed24]

Have you tried to heat up that area. If your having problems unscrewing it, take a heat gun and heat up the area where it threads in. They may have some factory thread locker on it. Heat it up to where its to hot to touch and should just unscrew! Righty tighty lefty loosey!!!

 

[KatoKevin454]

the leak is most likely the O-ring in the valve, if I remember right it is a #006 O-ring, Buna Nitrile 70 or 90 will work, you must use a large screw driver or round shaft as close to the inside diameter of the probe input hole, strap the cylinder tight with a leather belt double wrapped or a pair of channel locks ( you will mar up the finish with channel locks) insert the Screw driver or shaft into the Probe hole and twist it CCW, after removal there will be a screw in the bottom of the Valve, remove the screw carefully, it will a have springs and a plunger, the O-ring is on the end of the plunger, carefully replace the O-ring, I squeeze the O-ring to make it bulge out, then use a tooth pick to pry it off the plunger, use Silicone grease or Silicone Oil liberally to lube the new O-ring, reassemble, note: you don't need to tighten the valve end too tight, just snug it tight

 

[KatoKevin454]

CReilly1989, yours sounds like it needs a new Gauge, yours is a cylinder that looks different than the standard AT44 / Bullboss cylinder, they must have changed the design, but if it's leaking from the gauge weep hole, means the diaphram is leaking, replace the gauge.