FX 4 stage hand pump disassembly

[Metman2]

I'm looking for step-by-step instructions for disassembly of a 4 stage hand pump for filling PCP tanks. It is the "turbo model" made by FX and sold by Gehmann as m100. Neither of the two companies' service pages provide any detailed instructions for this pump. Replacement o-ring kits are available, but the accompanying "instructions" are pretty minimal.

I have an exploded parts diagram but this is not really helpful for getting started as there is a certain order that one must proceed. Parts are tightly fitted and one risks gouging or damaging parts if one is not careful. (I've repaired a Hill 3 stage pump so I have some experience).

An exhaustive internet search comes up with guides and video for other brands or for 3 stage pumps but they are different enough that it isn't clear where I should start.


So it's a real long shot that anyone here might have figured it out or know of anyone who has.... but I'm putting out inquiries everywhere....

 

[grauhanen]

You haven't yet asked on Canadian Airgun Forum. Perhaps some readers on that dedicated airgun forum have experience with this pump.

 

[GerardSamija]

This Youtuber hasn't shared any new videos for some years, but his old tutorial videos remain a tremendous resource. I keep a downloaded copy of this video available for when I get around to changing the seals in my now 8 year old FX pump. Mine's still working, if a bit cranky, but I should do it soon considering I bought the seal kit a couple of years ago...

 

[Metman2]

I managed to figure it out after some careful tapping and unscrewing. It is a different sequence than that of the 3 stage FX pump in the videos (both youtube and downloadable from Gehmann). There are two parts that slip on, held only by friction (grub-screws).

The biggest problem for me was that some of the threading was really frozen, and a couple of the tubes kept slipping in my vise. I found that wrapping in a piece of old bicycle inner-tube gave enough grip. I don't have the resources to make a youtube video but I can type out my steps, referring to part numbers. The funny thing is, the Gehmann part numbers are not the same as those from the FX site, for the exact same diagram!