Slow leak out of my Disco's fill nipple on the adapter!

[Canadianguy]

So i'm pumping up the Disco today when i let it sit and rest for a bit, it lost about 300 psi when I came back! I soaped the hose and fittings and nothing i could see that was bubbling.

Is that the pump doing that or the gun?

Greg

[leadslinger]

So i'm pumping up the Disco today when i let it sit and rest for a bit, it lost about 300 psi when I came back! I soaped the hose and fittings and nothing i could see that was bubbling.

Is that the pump doing that or the gun?

Greg

Maybe losing some from the valve stem?

[Cougar]

Having the same problem with a Maximus losing air. Pretty sure it's the valve stem leaking.

[Cougar]

Canadianguy, if you use a hand pump without a moisture filter you might want to check the valve stem for your leak. This is what I found in mine and it's not a very old gun.

[Canadianguy]

Didn't you get a moisture packs with pump? I've never seen anyone's that bad before lol we have the same weather. Mine looks new. Those need a makeover and moisture trap.

What does the inside of your foster fitting on the fill asmybly look like?

[Cougar]

The foster fitting was clean. No we didn't have a moisture trap and I'm sure that's what the cause. Going forward we aren't going to be using a pump anymore all our air will come from a bottle.
As you sure yours looks new? You said it's leaking and it's coming from somewhere. I'm betting my leak is from the dirty valve stem.

[Canadianguy]

What's the test for a valve stem? I'm not going that direction yet......I think I have pinned it down to either the check valve in the foster fitting or the threaded part that screws into the fill asymbley!

[Cougar]

I'm not sure how to test for a stem leak but this is what I do know. We never took this gun apart because of the air leak although it was still leaking when we striped the stock lug. Before the striped lug we had changed the complete end with a new one complete with check valve and still had a leak. But sure not from there. There is only two other places it can leak and that's the valve stem or the pressure gage. I'm betting on the valve stem. A new one comes with the O ring kit so I'll be replacing it. I'll let you know how it turns out.

[Canadianguy]

Roughly how long after you pump the gun does it take for the air to settle?

[Canadianguy]

I thought i got rid of this leak because I took the fitting off re taped it with the yellow Teflon tape. I actually can pump now up to 2200 or more with out the pump getting overly warm, so that part is fixed. I pumped it up to 2200, in 3 hours it went down to 1600 with some air in the balloon just tied off around the nipple. I've put the balloon around the whole fitting now see how it goes lol

If i'm understanding this right the guy I emailed at Hill pump said:

The most common fault we experience with Benjamin couplings is connecting to the end of our hose. If the manufacturing tolerances of the cone seats are not at 60 degrees there is a possibility that it will leak if just finger tight. As it’s a metal to metal fit, spanner tightening really hard will compress the metals together forming the seal. This resolves the problem in 99.9% of cases.

[Canadianguy]

Here is the Foster coupling from a rifle foster nipple to the hand pump fitting.

[Canadianguy]

I bought a new foster nipple and I'm happy to say that i haven't had any leaks since pumping it up last Thursday:)

[Doc Sharptail]

That's good news.

-D.S.

[Cougar]

The Maximus is back together and better than it was when new. Two things, first is there are big differences between the Maximus and discovery so the parts are not interchangeable. The valve screws are in different locations and the fill end is different as well so if you want a discovery valve you have to change everything. I ordered a discovery tube because it was available and the Maximus tube was on back order with no idea as to when I would get it and was told they are both the same. Well when it arrived i went about to put it back together and soon found out nothing was the same. The old tube with the striped screw wasn't going to work so I had no choice, back I went to buy a valve and the a fill fitting and of course new screws for the valve. Might as well just bought a new gun and used this one for parts by the time I got done but on the up side this gun now shoots 920 FPs with 16g pellets. Guess it's really pretty much a discovery now with a long barrel.

[Canadianguy]

When I started my Discovery build I bought the tube and all the internals first