Brocock/BRK Need some help with a BRK atomic and hand pump

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M777

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Oct 6, 2019
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Midwest, United States
I acquired a .177 atomic late last year. Came pre charged, shot two mags out of it, checked for leaks and put away during the unexpected busy work season.

Now I came back to it, but can’t pump it to save my life with a four uncles hand pump. Pumps up just fine until the line builds pressure, then it’s impossible to pump any further. Tried cocking it, no difference. Pressure is slightly above 100 bar, not attempting to charge from zero. Unfortunately I bought the hand pump during Black Friday and it’s well out of the return window (if it’s even the pump that’s at fault). Have a notos and four uncles pump at my vacation home, so I’m not new to hand pumping and know what’s involved.

What could be the likely culprit here? Checked the cigarette filter, it’s not plugged. Unfortunately I don’t have another pcp, hand pump, or compressor to test further. I’m inclined to think it’s an issue with the pump. Any suggestions would be appreciated!
 
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Look around the Four Uncles handpump box for one of these deadhead test plugs. Insert in female quick-disconnect fitting at end of fill whip (hose) and pump. If handpump fills and holds pressure, problem lies elsewhere. WM
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WorriedMan said:
Look around the Four Uncles handpump box for one of these deadhead test plugs. Insert in female quick-disconnect fitting at end of fill whip (hose) and pump. If handpump fills and holds pressure, problem lies elsewhere. WMView attachment 554023
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I will try that tomorrow in the morning thanks. Trying to think everything through, but it seems like it just stalls as soon as the pressure builds up in the fill line.
 
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M777 said:
M777 said:
I will try that tomorrow in the morning thanks. Trying to think everything through, but it seems like it just stalls as soon as the pressure builds up in the fill line.
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If pump is acting up, clean check valve. Coby, of Topa Manufacturing Company, has Chinese handpump tear-down videos on YouTube that helped me. Might be one-way valve in Atomic is stuck, few drops silicone oil in male foster fitting, or inserted fill probe end, allowed to soak overnight, might help loosen. WM
 
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WorriedMan said:
If pump is acting up, clean check valve. Coby, of Topa Manufacturing Company, has Chinese handpump tear-down videos on YouTube that helped me. Might be one-way valve in Atomic is stuck, few drops silicone oil in male foster fitting, or inserted fill probe end, allowed to soak overnight, might help loosen. WM
Click to expand...
I will try that, thanks!
 
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L.Leon said:
@M777, when you say impossible, what does that mean? Full body weight on the pump won’t crack the valve in the Atomic? When I ran into a similar issue the problem was with the pump. I own a HPA compressor and still handpump both my Atomics. I suspect the pump…
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Yes, full body weight (170 ish lbs). Im guessing the pump is the issue also. Will likely look into it tomorrow. Thanks!
 
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When you can’t pump it is the handle/pump stuck in the fully up position? If so I am assuming you feel pressure inside the pump pushing it back upward?? If this is the case it is most likely just the little oring in the check valve in the very bottom of the pump. It’s supposed to keep pressure as you pump from flowing back upward into the pump itself. I think it’s like an 006 oring.
 
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Trucker3573 said:
When you can’t pump it is the handle/pump stuck in the fully up position? If so I am assuming you feel pressure inside the pump pushing it back upward?? If this is the case it is most likely just the little oring in the check valve in the very bottom of the pump. It’s supposed to keep pressure as you pump from flowing back upward into the pump itself. I think it’s like an 006 oring.
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I would say it gets stuck at around the half way mark. Yes, exactly, pressure builds up in the line and can’t pump any further than that. I will try to tear into it later, thanks.
 
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M777 said:
I would say it gets stuck at around the half way mark. Yes, exactly, pressure builds up in the line and can’t pump any further than that. I will try to tear into it later, thanks.
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I bet pressurized air is seeping into the pump body. On my pumps if you un screw the pump body from the foot base the check valve is right in the bottom of the base. It un screws and is on a spring. You should see a small oring on the end of the part that sits on the spring. That is the culprit if the check valve is causing the issue.
 
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Trucker3573 said:
I bet pressurized air is seeping into the pump body. On my pumps if you un screw the pump body from the foot base the check valve is right in the bottom of the base. It un screws and is on a spring. You should see a small oring on the end of the part that sits on the spring. That is the culprit if the check valve is causing the issue.
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Was able to get to it thanks!
 
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Update:
Was able to get to the check valve. Cleaned it out and installed a new silicon greased o ring, re assembled and same issue. Also tested with the dummy plug, can only get it to pressurize up to 2500ish psi before it stalls. Whatever is wrong with it, is beyond my mechanical abilities.

Going to have to look for an alternative. In the process of moving, I lost a nib compressor, going to have to keep looking for it at my parents house and at my new house.

I very much appreciate all the input.
 
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Update 2:
Good news I found my compressor that was missing during my move.
Bad news, the power supply blew (audible pop inside the supply box and complete loss of power, rifle gauge wouldn’t budge and mistakenly thought it would build pressure slowly) within a few minutes of trying to supply air to the rifle directly. Now in shopping for a new power supply on Amazon (600 watt 50 amp).

Now I’m sure the valve inside the rifle is completely stuck. Would buying a tank and blasting air into it work (or even be safe in this scenario)? I’m pulling my hair out at this point.
 
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M777 said:
Update 2:
Good news I found my compressor that was missing during my move.
Bad news, the power supply blew (audible pop inside the supply box and complete loss of power, rifle gauge wouldn’t budge and mistakenly thought it would build pressure slowly) within a few minutes of trying to supply air to the rifle directly. Now in shopping for a new power supply on Amazon (600 watt 50 amp).

Now I’m sure the valve inside the rifle is completely stuck. Would buying a tank and blasting air into it work (or even be safe in this scenario)? I’m pulling my hair out at this point.
Click to expand...
In this hobby using something then setting it aside for an extended period can cause problems. Compressed air, without sufficient moisture-removal, is likely to induce corrosion on metal parts. Not sure if Atomic uses fill probe or has an installed male foster fitting, either way, few drops of silicone oil in foster fitting or open end of inserted fill probe, left to soak overnight, might loosen one-way valve. Position gun so silicone oil contacts one-way valve. Dismantling and cleaning is next step should oil-soak not work, search out a "how-to" video on YouTube. WM
 
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WorriedMan said:
If pump is acting up, clean check valve. Coby, of Topa Manufacturing Company, has Chinese handpump tear-down videos on YouTube that helped me. Might be one-way valve in Atomic is stuck, few drops silicone oil in male foster fitting, or inserted fill probe end, allowed to soak overnight, might help loosen. WM
Click to expand...
Here is the link
 
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WorriedMan said:
In this hobby using something then setting it aside for an extended period can cause problems. Compressed air, without sufficient moisture-removal, is likely to induce corrosion on metal parts. Not sure if Atomic uses fill probe or has an installed male foster fitting, either way, few drops of silicone oil in foster fitting or open end of inserted fill probe, left to soak overnight, might loosen one-way valve. Position gun so silicone oil contacts one-way valve. Dismantling and cleaning is next step should oil-soak not work, search out a "how-to" video on YouTube.
Click to expand...
I will try the silicon oil soak as a last resort before tearing into it, thanks. Funny thing is that this thing is practically brand new, except for the few shots that I took with it when I bought it (no chance for moist air to be filled into it).
 
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M777 said:
I will try the silicon oil soak as a last resort before tearing into it, thanks. Funny thing is that this thing is practically brand new, except for the few shots that I took with it when I bought it (no chance for moist air to be filled into it).
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Possible those who originally charged it weren't on top of things. I bought two airguns, one was a promotional loaner, another a customer return, both were sold as brand new, with no mention of previous activities. Problems led to discovery of past lives. WM
 
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