Can anybody help with the AF pump?

Home Forums AirForce General Chat Can anybody help with the AF pump?

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    FX pump diagram:


    Random notes from random sources on pump repair:

    BAM pumps:

    [Losing air] after bottoming out,and wont pass about 1500 psi, then
    the problem is the 3rd stage seal.

    Pull the whole thing apart,being very careful not to lose the little rubber BB
    in the upper cap(intake valve)(There’s a bigger one in the base,but it seems
    to stay put)Clean it all out,and radius and debur the entry to the 3rd
    stage(innnermost) tube.Also lightly radius all edges of the o-ring groove on
    the 3rd stage pump.

    Get some icemaker 1/4″ nylon tube,put about an inch on a 3/16″ drill bit in your
    drill(or lathe)on the shank(smooth part)and cut some rings just a little
    narrower than the o-ring groove,while spinning,with a sharp hobby knife.
    While they’re still on the drill,cut each one across at about 45 degrees.These
    are your piston rings.The ID is a little small,so put a couple wraps of glide
    dental floss in the groove to keep you piston ring centered.

    Install and reassemble.This seems to get around the problem of the 3rd stage
    o-ring wearing and getting cut.It may take a couple tries to get the packing
    and width just right,but mine is now easily hitting 3000 psi,10 fills and still

    Axsor Gen 1 pumps:

    Theres an article in the Airgun Letter by Tom Gaylord on maintaining the
    pump. You unscrew the base from the tube, (unscrew the rectangular piece
    from the pump tube) Then dump all of the ball bearings onto a rag then rinse
    in degreaser and dish detergent then dry real well and remove all oxidation.
    Wipe the internals of the rectangular bottom pump piece with air chamber
    lube(for spring guns) then when the balls are dry then dump back into
    the pump and put a few maybe 3 or 5 drops of the air chamber lube then put
    the pump back together(twist the tube back onto the rectangular piece then
    shake the pump to distrubute the lube on all of the balls, then plug the hole
    where your air comes out of to fill your gun and pump to 3000 then quickly
    unscrew the bleed screw to let all the air out and do this 2 to 5 times. Then
    your pump is good as new, even better than new.

    Use RWS air chamber lube and do not use anything else. Only about 3 to 4
    bucks or less for a small bottle of this needed air chamber lube. Do this about
    every 3 months to 6 months.Depending on humidity and dampness where you
    live. Less if dry and no humidity.

    Axsor Gen 2 and early FX pumps:

    Remove the bottom black body from the tube, on the bottom of the tube
    assembly is a porbe that goes down into the glass beads, remove the probe,
    inside the bottom of the tube assembly is a bullet shaped valve , be careful the
    valve is closed by a small spring and the valve will fly out if you are not
    watching, on the valve is an oring that you need to replace. I was unable to
    find the correct size oring locally so I actually used one that was a little
    oversized but it seems to be holding up well.

    Newer FX pumps:

    The FX is easy to disassemble I have cleaned the FX pump twice and replaced
    the check valve O ring twice. If your pump is leaking down under pressure it
    could be a bad check valve O ring. If the handle wants to rise at the bottom of
    the stroke and you can see the gage dropping check the valve. You can
    separate the pump from the block with two adjustable wrenches one wrench to
    hold the block the other for the nut at the base of the pump tube. After the
    pump tube is separated from the block you will see a brass nozzle you will
    need a pair of water pump pliers and a little duct tape to protect the brass
    from the pliers teeth. Wrap the brass with tape with a firm grip on the pliers
    unscrew the nozzle you will find a spring in the nozzle and the valve in the
    base of the pump tube. Check the O ring for a cut or debris I think I used a
    #005 Viton as a replacement all of the other O rings in the pump were fine.

    Reassemble in reverse order screw the pump body back into place slowly
    listening for a crunching sound if you hear it shake the block to move the
    desiccant balls away from the nozzle to avoid breaking them.

    Also re: recent FX pumps:

    The FX can also be rebuilt but with more difficulty due to the lack of hex
    shaped parts especially around the check valve. The FX check valve is located
    inside a cone shaped piece that requires the fabrication of a special tool to
    unscrew it or you could go the old vise grip route to unscrew it. The FX uses
    desiccant balls(glass) in its base that will crush if careful attention is not paid
    during reassembly and they need to be washed and dried if you reuse them.
    The HILL has hex shaped parts or a set of flats on the critical parts and the
    filter is a one piece porous tube that is replaced with each service and nothing
    will crush during reassembly.

    Apologies to the original authors.



    Thanks wvanryper,

    This is going in the Quick Reference section right now.


    Well so far no luck.

    I got the pump unscrewed from the bottom half, and the bottom valve looks almost identical to the Hill. The little pointed plunger has a small o-ring which is in good shape. The valve assemblies are pressed into the inner tube on both ends, so removing them to get to the center rod is near impossible.

    Everything I can see looks ok, o-rings not cracked or mashed. Greased up and reassembled but pump just will not work.

    I guess Im gonna have to try and drive the valves out of the inner tube somehow. Maybe like knocking delrin bushings off a barrel?

    Damn squirrels are outside laughing at me. If they dont stop, I will be bringing out the .17HMR.


    I’ve just got the same problem? Have you got yours fixed?


    when I sent FX an email they replied with

    no problem to send it to states just shipping i guess ca 20 euro for kit+stamps i guess airguns of arizona have em cheaper for you paypal is ok”

    They have it listed on their sight under FX pricing, but I have not contacted them yet.

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