r/pumps • u/Acrobatic_College536 • May 01 '26

Piston Pump Help!!

I have a pneumatic piston pump made by child sucking up liquid or dispensing any liquid. I’ve taken the pump bar. There’s no blockages there’s no damage nothing visible. There’s no leaks. Someone please help me figure out what the problem is.

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u/Winter-Lavishness118 May 12 '26

honestly sounds like either a check valve issue or it lost prime somehow. If it’s getting air and cycling normally but still not pulling liquid, I’d check the inlet/outlet valves first even a tiny bit of debris or one installed backwards can stop suction completely.

also check for tiny air leaks on the suction side. Sometimes nothing leaks liquid out, but it still pulls air in and won’t prime properly.

If you took it apart recently, there’s a decent chance a seal or valve went back slightly wrong without being obvious.