Nelson Leak

Sexy_Chicken · 07-31-2006, 07:54 PM

Okay so I have a Nelson (my TAG Nelson) that's leaking down the barrel. I figured this was in some way related to the cup seal, but first tried making sure everything was clean/lubed to make sure it was nothing due to improper maintenance, but no dice.

Next I checked to make sure the power tube wasn't cracked or any of that business, but everything is fine. The cup seal looks fine as well, but I replaced it for the hell of it.

I dropped some lube in the ASA and gassed 'er up. It's pissing down the barrel still, but after a few shots, it stops. I fire about 30 more times to work in the lube, and it occasionally leaks after a shot or two, which started to grow more consistant (leak-wise) towards the end, which is where I am now. I tried the valve off of another gun I have and it worked fine, so then I just swapped in the tube, nut, seal, and spring and it still worked, so I'm not too sure what it is exactly that's causing the leak with the other valve.

I'm assuming/hoping it's something glaringly obvious that I just overlooked, so if anyone has any insight, I'd much appreciate it!

Phantom Power · 07-31-2006, 08:32 PM

If you've tried a new cupseal and still got the problem, it's probably a nick or gouge in the valve retaining nut. Check the lip that the cup seal seals against. You can always put some Crest toothpaste on a flat surface and spin the lip against it to try and polish it smooth again.

Sexy_Chicken · 07-31-2006, 08:55 PM

Nope, it's not the valve retaining nut either, as I have 2 others that I've tried it with and have had no luck with any of them.

Phantom Power · 07-31-2006, 09:00 PM

Try a stronger valve spring maybe ?

Sexy_Chicken · 07-31-2006, 09:23 PM

Ahh, thanks for reminding me about that. I forgot to post that I did try different spring combinations, power tubes, and velocity adjustment since I had a leak in the past that was in some way attributed to velocity being ridiculously high. The only thing I noticed upon changing springs was the intensity of the leak. Weaker valve springs resulted in a more "violent" leak. I fiddled around with it again a couple of minutes ago trying to think of something else to swap/test, but ended up just trying a couple of things I've already tried (power tube and valve nut), with no luck

.

Z50 · 07-31-2006, 09:33 PM

Remember that a cup seal will need a few hundred shots to seat properly, that said, you have probably gone through a few shots testing these various spring combos. Make sure everything is smooth between the cup seal and the valve seat. It may be worth getting some fine sand paper and smoothing everything out. Inspect the jet holes on the power tube, I was working on a trracer with a similar obnoxious leek and it was vary difficult to see the hairline crack that was causing it. Finally be sure that you have an o-ring between the valve seat and valve body.

PJ · 07-31-2006, 09:51 PM

Did you happen to chage out the main spring when you were going through the valve springs? It could be too strong or too long, both of which could push the hammer into the valve tube, opening it just a tad.

Sexy_Chicken · 07-31-2006, 10:44 PM

I want to say I put somewhere around 500 shots through this (1 full fill of a 3.5 oz and about 300 psi from my brother's 68ci HPA tank), so both cup seals should be broken in or pretty well on their way.

2 of the power tubes tested were NOS Lapco #6s that went in straight from ASP, with the other being extremely thoroughly inspected with no signs of stress marks anywhere.

As for swapping main springs, I did test two others than the one I originally had in there. They're all the same length, but only 1 was a harder spring (red), so I'm not so sure it's that.

One thing that caught me a little off-guard from the start was that the original cup seal in the gun was a Black Magic, which I've never had any problems with or heard of any problems with, leading me to believe it may be something else.

I just spent 20 minutes going through every possible power tube, valve nut, cup seal combo I can again and still am having 0 luck. Right now the springs I have in are a red valve spring and yellow main spring, which seem to provide the "softest" leak.

Any other unconventionaly leak stories that may have an unconventional fix?

Lrrpie-CT · 08-01-2006, 08:39 AM

Did you try a new valve retaining nut o-ring?

Maybe you are just hearing phantom leaks? (pun intended!)

How about this: Assemble your valve guts and ASA and screw it onto a tank while the ASA is detached from the gun. Does it leak?

kidneythief · 08-01-2006, 02:40 PM

My money would be on the valve retaining nut o-ring.

-Jake

07-31-2006, 07:54 PM	#1 (permalink)
Sexy_Chicken Seasoned Member Join Date: Mar 2006 Location: South Joisey	Nelson Leak Okay so I have a Nelson (my TAG Nelson) that's leaking down the barrel. I figured this was in some way related to the cup seal, but first tried making sure everything was clean/lubed to make sure it was nothing due to improper maintenance, but no dice. Next I checked to make sure the power tube wasn't cracked or any of that business, but everything is fine. The cup seal looks fine as well, but I replaced it for the hell of it. I dropped some lube in the ASA and gassed 'er up. It's pissing down the barrel still, but after a few shots, it stops. I fire about 30 more times to work in the lube, and it occasionally leaks after a shot or two, which started to grow more consistant (leak-wise) towards the end, which is where I am now. I tried the valve off of another gun I have and it worked fine, so then I just swapped in the tube, nut, seal, and spring and it still worked, so I'm not too sure what it is exactly that's causing the leak with the other valve. I'm assuming/hoping it's something glaringly obvious that I just overlooked, so if anyone has any insight, I'd much appreciate it!

07-31-2006, 08:32 PM	#2 (permalink)
Phantom Power Pump Gun Dealer Join Date: Mar 2006 Location: Pender Island, BC	If you've tried a new cupseal and still got the problem, it's probably a nick or gouge in the valve retaining nut. Check the lip that the cup seal seals against. You can always put some Crest toothpaste on a flat surface and spin the lip against it to try and polish it smooth again. __________________

07-31-2006, 09:00 PM	#4 (permalink)
Phantom Power Pump Gun Dealer Join Date: Mar 2006 Location: Pender Island, BC	Try a stronger valve spring maybe ? __________________

07-31-2006, 09:51 PM	#7 (permalink)
PJ Hawaiian-shirted hooligan Join Date: Apr 2006 Location: Powell, TN	Did you happen to chage out the main spring when you were going through the valve springs? It could be too strong or too long, both of which could push the hammer into the valve tube, opening it just a tad. __________________ Paul AIM: PJDarknight CPPA #1145 / PPIG #496 / LPPC #103 / POG #1047 / Team Rogue Cell #7 PJ's Gallery on MCB Feedback on MCB

08-01-2006, 02:40 PM	#10 (permalink)
kidneythief Lord humungus the Mod Join Date: Mar 2006 Location: Home Finally!!!	My money would be on the valve retaining nut o-ring. -Jake __________________ "I wish simply to be a decent person, yet I will always fear the retards" -Brian Hindt(geech) MCB Moderator Kidney Machine

07-31-2006, 08:55 PM	#3 (permalink)
Sexy_Chicken Seasoned Member Join Date: Mar 2006 Location: South Joisey	Nope, it's not the valve retaining nut either, as I have 2 others that I've tried it with and have had no luck with any of them.

07-31-2006, 09:23 PM	#5 (permalink)
Sexy_Chicken Seasoned Member Join Date: Mar 2006 Location: South Joisey	Ahh, thanks for reminding me about that. I forgot to post that I did try different spring combinations, power tubes, and velocity adjustment since I had a leak in the past that was in some way attributed to velocity being ridiculously high. The only thing I noticed upon changing springs was the intensity of the leak. Weaker valve springs resulted in a more "violent" leak. I fiddled around with it again a couple of minutes ago trying to think of something else to swap/test, but ended up just trying a couple of things I've already tried (power tube and valve nut), with no luck .

07-31-2006, 10:44 PM	#8 (permalink)
Sexy_Chicken Seasoned Member Join Date: Mar 2006 Location: South Joisey	I want to say I put somewhere around 500 shots through this (1 full fill of a 3.5 oz and about 300 psi from my brother's 68ci HPA tank), so both cup seals should be broken in or pretty well on their way. 2 of the power tubes tested were NOS Lapco #6s that went in straight from ASP, with the other being extremely thoroughly inspected with no signs of stress marks anywhere. As for swapping main springs, I did test two others than the one I originally had in there. They're all the same length, but only 1 was a harder spring (red), so I'm not so sure it's that. One thing that caught me a little off-guard from the start was that the original cup seal in the gun was a Black Magic, which I've never had any problems with or heard of any problems with, leading me to believe it may be something else. I just spent 20 minutes going through every possible power tube, valve nut, cup seal combo I can again and still am having 0 luck. Right now the springs I have in are a red valve spring and yellow main spring, which seem to provide the "softest" leak. Any other unconventionaly leak stories that may have an unconventional fix?

08-01-2006, 08:39 AM	#9 (permalink)
Lrrpie-CT See Matt Mod. Join Date: Mar 2006 Location: Bethlehem CT	Did you try a new valve retaining nut o-ring? Maybe you are just hearing phantom leaks? (pun intended!) How about this: Assemble your valve guts and ASA and screw it onto a tank while the ASA is detached from the gun. Does it leak?

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