Vevor hand pump...

In the PP instructions they show a little rubber/neoprene ball, about 1/4 inch diameter. It doesn't say, but that ball is in the parts bag. Are you supposed to install that before you use the pump?

Anybody else bought one of these pumps? Can you give me some guidance. I hesitate to hook it to the gun and lose the air already in it. There is a o-ring on the barrel of the pump and I don't see what it is supposed to seal. It talks about oil in the PP instruction sheet but doesn't say what kind of oil.
 
Re-seal/repair kit has extra rubber ball, pump will already have one installed. You might find a brass plug which fits in foster fitting, at end of fill hose, to be used for pressuring up pump to test for leaks. Coby Leo, of Topa Manufacturing Company, has a two-part repair video on YouTube for these pumps, very informative. Heavy weight silicone oil is used for lubrication, same stuff treadmills use, can find on Amazon. WM
 
WNYBill,
Sorry, should have read your post better, I'll try to answer questions. My hand pump uses "O" Rings as "cushions" to absorb shock of pumping between metal parts, possibly yours, too. All my PCP air gun tanks, bottles or tubes have one-way valves at feed port, installing a fill probe or attaching to a foster fitting does not release any stored air. WM
 
Test plug
IMG_20220326_223819.jpg