Gehmann hand pump problem

[PantelisTsk]

Hello. I have a Gehmann 200 hand pump (not exactly new) that a while back was working normally.
The pump now can not be used as before when the manometer's reading is about 50 bars (the handle is not easy to pull all the way up or push all the way down), rendering it inoperable.

Has anyone encountered the same problem succesfully before? Due to this problem I am almost in a precarious position according to my air rifle shooting competitions coming up.

Thanks in advance

[BigAl]

Sounds like you might need to have it re-sealed. If the pump is much over three or four years old, and has been used regularly, then I would consider it end of life and just replace it. The metal components of the pump wear as well as the seals, this wear basically causes the seals to very quickly fail again. Sorry if this is not good news for you.

Alan

[Rover]

Don't bust your hump, get rid of the pump!

A SCUBA tank won't break your bank.

[BigAl]

Yes a Scuba type tank is a much better proposition. I did not notice a location for you, but here in the UK we can get 7 lt 300 Bar cylinders, with surface use only valve with integral gauge (so only need a five year test), for about £20 more than a pump. The dealer that I occasionally work for hardly sells any pumps anymore, with the cylinders so close in price.

Alan

[PantelisTsk]

I considered buying a scuba tank, however it's not a realistic solution as they are pretty expensive here in Greece and I will be studying for another 6 more months away from my home city where I regurarly train in air rifle. It would have been a good solution three of four years ago but buing one now will be almost in vain.

I will try to re-seal it tomorrow as BigAl at first suggested, with new o-rings. Or try to find another one for six months.

[Andre]

Try removing any water from the pump. If you don't use the bleed screw (I think that's what it is) and just unscrew the tank from the pump when done filling, it will leave water in the pump. Not bad, but hurts pumping efficiency. With the tank and any adapter from the pump, pull up on the pump handle rapidly. You should see a whitish air spray from the pump. So this several times till no spray is left. This will remove air from the pump.

If this hasn't helped things, reseal your pump.

Regards to pump vs scuba tank, I use the same Gehmann pump to charge my FWB 700 tanks. It works fine and doesn't take too long. Plus on a 3k scuba tank you only get one true fill.

[PantelisTsk]

Apparently the pump needed some servicing and now is as good as new.
Too much lubricant oil over the years hampered it's use and needed some inside cleaning. I only used it once but it's working properly now.

[muldoon9]

Mineral oil always oxidizes and causes a varnish mess.
Get yourself some 100% synthetic.
M

[David W. Johnson]

I just got a pump and wondered about maintenance. I found a tutorial on the pyramydair site. The author said he rebuilt dozens when he worked at pyramid. He claimed the only causes of failure he ever saw were owners taking them apart and not being able to put them back together, or operators not allowing them to cool down after five minutes of use. He said using the drain after each use was about you needed to do and advised against lubricant. I would have thought lubricant would be good from time to time so long as you use the synthetic non-flammable sort.