Leaky N Loose Reservoir Cap

[marauder]

Tiff's XP 270 leaks from the reservoir cap cuz it won't seal all the way. It's fine if you hold the gun parallel to the ground, but if you lay it on the ground when it's full, or tilt it or whatever water starts coming out from around the cap. I am going to try a new cap when we get back to my house. If that doesn't work then I'll try putting electrical tape around the threads, but not sure if that will work. Any other ideas?[*]

[Andrew]

The only issue with electrical tape on the threads may be the two flat areas on the side of the filler hole (front and back I think) which won't give an even seal. It's still worth a try though, and will probably help make the cap less loose anyway.

What's happened to the washer in the cap? That washer should be all you need to seal the cap. I'm guessing water isn't coming through the one-way air valve in the cap, but from the base of the cap (i.e. past the threads). If there are any imperfections on the sealing face of the filler hole, then it may leak from there. if that is the case, filing / sanding down any small imperfections, or filling (then filing) any large ones should improve the seal (providing the whole sealing face is completely smooth, flat and parallel to the washer after filing. Any dips in the filler hole sealing face will be a source of more leaking.).

[martianshark]

Teflon tape.

[Andrew]

Teflon tape.

If you can find a way to make it stick to the threads without coming off all the time, then yes this would work.

[martianshark]

Friction.

[marauder]

You're right, it doesn't leak out of the one-way air valve in the cap, it's coming out from under the cap whenever the gun is laid on its side or tilted back. It may be the rubber washer, but I'm not sure how to check if that's the case. I have never used Teflon Tape? What is that exactly?

I may not get to fixing this until I'm back for good, but I'm definitely going to get to it.

[scottthewaterwarrior]

If it is a problem with the cap, I can give you my spare. I had an XP-270 once apawn a time, I threw it out a while ago (the whole reservoir shattered into like 50 pieces), if I can find the old cap (I had the good since to keep it), you can try it out. If it works, it's yours!

Some times guns just leak, I was really mad when I bought 15 Max-D 2ks at Target and every single one leaked (clearly a factory defect).

Edit (one minute later): Found it!

The one thing is though, I would recommend trying any other ideas you have first. The XP 270 is a tethered cap, to get it off and put mine on is to loose the tether.

[Andrew]

Teflon tape, isn't really tape. It's just a sort of thin sealing strip. It isn't adhesive, and constant doing and undoing of the threads pulls the 'tape' off the threads. I'm, not sure Teflon tape will be effective at sealing the threads anyway. They are only really useful on 'tapered' threads but, although the cap looks tapered, I'm pretty sure the actual threads are 'parallel'.

The XP 270 is a tethered cap, to get it off and put mine on is to loose the tether.

Not completely true, you can get the cap out with the tether intact. At the front and back of the filler hole, there are flat areas on the threads (at the seam between the two halves of the reservoir). Inside the filler port, next to these flat areas, there are kind of notches which were made when the reserovoir was sealed together. The cap's tether can (just) fit through if the anchor is vertical (side-on) to the hole.

If you need me to, I'll put pics up.

It may be the rubber washer, but I'm not sure how to check if that's the case.

To be honest, unless the filler port has a hole in the base of it, I can't think of anything else that would cause it too leak.

The washer, the sealing face on top of the filler port, the sealing face under the washer in the cap, or the air inlet valve are the only real sources of leakage, other than a damaged reservoir (small holes in the filler port wall maybe?).

Imperfections in either the washer itself, on the top of the filler port sealing surface or the sealing surface in the cap (as earlier posted) should be the only things that can cause leaks.