6 replies to this topic

[AssassinNF]

My friends AT3K broke two days ago, and I have been attempting to fix it.

I've determined that the problem is the check valve in the pump. The pump now lets air in and out of the tank, so when you try to pump it, the pump shoots back out when you let go, "un-pumping" it. It feels like a strong spring suddenly materialized inside the pump.

I just finished replacing the pump with another 3k pump I happened to have lying around, and the gun now works fine, prooving that the problem was the pump.

Even though the gun now works, I'm still wondering if there is any way to fix the pump I took out of it, as I may use it later. Has anyone here had a 3k check valve break like that, and does anyone know of a way to fix it without basically performing an autopsy on it?

[Jtcm]

You should be able to get little check valves at pet stores in the aquarium section they only cost a few dollars and should be small enough to fit in the at3k shell and they don't have much internal volume so "dead space" isn't really to much of a problem.

[BlackFox]

I've had similar things happen with other pumps.
Yeah, without performing said autopsy, there's really nothing to do except replace it.

Are you sure it's letting air in and out? The way you described the pump shooting back out makes me think that the check was forced shut and the air isn't getting in at all and you're pushing the same volume of air back and forth inside the pump tube.

I don't remember what gun it was, but I remember dremmeling the output hose connector off on one pump and some bits of plastic fell behind the check valve and kept it from opening.

[nerfboi]

http://www.petsmart....oductId=2755280
Would this type of thing work? It's a "one way" tubing

[Aimless]

Yep, it'll work fine. You also get a bit of tubing with it

[AssassinNF]

I've had similar things happen with other pumps.
Yeah, without performing said autopsy, there's really nothing to do except replace it.

Are you sure it's letting air in and out? The way you described the pump shooting back out makes me think that the check was forced shut and the air isn't getting in at all and you're pushing the same volume of air back and forth inside the pump tube.

I don't remember what gun it was, but I remember dremmeling the output hose connector off on one pump and some bits of plastic fell behind the check valve and kept it from opening.

I'm sure. I know it still lets air in because you can pump it, hold the pump compressed, pull the trigger, and air shoots out the barrel (only one-pump's worth, of course).

So instead of "pushing the same volume of air back and forth inside the pump tube", I'm just pushing the same volume of air in and out of the tank.

So the only way to use this pump is if I buy a check valve. Would anyone happen to have a McMaster part number for one?

[nerfboi]

I got this off of CaptainSlugs DIY external Tank thread
51055K171 - White Acetal Check Valve for 1/4" Tube OD = $11.74

Thanks to CaptainSlug for that.

Edited by nerfboi, 27 August 2008 - 08:16 PM.