Benjamin Hand pump lets out all air

[Mitchees]

Hey all,

New to the pcp game here. So I noticed last time I was pumping, I would pump up to 3000psi like normal and when I bleed the hose on my pump I would lose around 1kpsi. Now, when I bleed the hose on my pump, all of the air just comes out and it goes down to 0psi.. not sure what is causing this problem. Any help would be greatly appreciated. Thanks!

 

[rcarlisle]

You should open the bleed quickly and completely. If you are slowly opening it and letting the pressure out over several seconds, that's probably the problem. If you are bleeding abruptly and still losing significant or all pressure, I would tend to suspect the fill port on the gun.

 

[starlingassn]

yep ,crack the bleeder open fast,
if you go too slow you can empty the gun.

 

[Mitchees]

Appreciate the responses guys. Cracked the bleed screw fast and still is emptying to 0..

 

[Trucker3573]

Yeah I was going to say I have never experienced a gun emptying no matter how I bled a line. It’s the fill port on the gun sticking open. Maybe it is just some debris in it. Maybe try adding a couple of drops of silicone (make sure it’s pure silicone) oil into the fill port and try airing it up again. If that doesn’t do the trick then the area will have to be disassembled, cleaned and probably a new oring installed.

 

[lwm211]

Make sure the gun is cocked before starting to pump

 

[WorriedMan]

Mitch,
Have to go with Trucker on this, especially since it seems to be getting worse. One-way valve in gun is likely problem, debris or corrosion build-up. Few drops heavier grade silicone oil, like the kind used to lubricate treadmill exercise machines, would be first step, disassembly would follow if no change. Best of Luck, WM

 

[Mitchees]

Thanks for all the responses. Yes, dirt in the fill port makes sense to me. Gonna search for some maintenance videos and hopefully clear it out. I’ll post the results afterwards

 

[DesertSilver]

I had the same problem with filling my Sumatra with hand pump. Opened the valve all of the way but it wouldn't bleed fast enough to close the check valve. My tank fill station vents the air fast enough and I don't have that problem. My new fill station does the very same thing and figure it's the diameter of the hose not moving enough air quickly enough. I have 2 tanks and fill stations.

 

[KatoKevin454]

I find it's mostly the O-ring in the fill port that is sticking or has dried out and hardened, you can replace the fill port O-ring and lube it with silicone oil or silicone grease, it will take a Duro 70 #006 O-ring buna nitril or 1/8x1/4x1/16
look up chart here great place to buy O-rings too in bulk

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