Foster fitting problem??

Forums PCP Airguns Foster fitting problem??

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    ironlion269
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    After just four rounds of refilling my new Marauder's tank I am unable to get the gun to accept any air. My last attempt had the gun at 1000 psi and it still wouldn't allow any air to pass the fitting. I am using a factory-new Benjamin pump but it is the Foster fitting on the rifle that has me concerned. Does the fitting in the attached photos look defective?

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    Hajimoto
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    Looks normal to me. I answered your PM with more to look into. Worst case, degas, remove nipple, swap out with another or soak in white vinegar for 5 hours and rinse 

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    Eaglebeak
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    It looks like somebody has tried to poke the filter with something pointy. It is more likely that the valve behind the filter is stuck or blocked, perhaps with some of the filter fragments. Was the gun a display model where it could have been tampered with? Or did it come in a sealed box? It's a new gun, just send or take it back.

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    airgunfans
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    you can remove that foster male and plug it to the output of the pump. if air can pass through, the connector is not to be blamed.  

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    Stefanjan
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    My wildfire had the exact same issue.  I pulled the fitting and there was gunk lodged in it.  After pulling it apart and cleaning it all up it went back to working perfect.  I chalked it up to the cheapnees of the gun but perhaps it is a problem factory wide?  The gunk im pretty sure was some.kind of thread lock.  Black in color and a.bit.greasy.  perhaps teflon tape that got greasy?  Wish I had thought to take pix.

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    ironlion269
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    Thanks for all the replies!

    I'll pull the fitting off tonight and look into the top of the degassed reservoir.  see if I can't pull out any debris or "gunk" that may be blocking the inlet.  I'll attempt the pump disassembly and lubrication with silicone grease as Hajimoto suggests.  I've watched a thorough video on doing so and was frankly a little intimidated by the complexity of the 3-stage pump.  I felt the same way before my first attempt to work on tuning my Crosman springers so I'm sure I'll be OK.

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    spysir
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    Good Morning.

    Now you are looking at the fill assembly not "into" the reservoir eh.

    "Item # 3" fill adaptor:

    https://www.crosman.com/pdf/manuals/1763%20&%202263%20EVP%20&%20PL.PDF

    might be the wrong Gen, it doesnt matter.

     You didnt mention pump problems but I hate rebuilding some of those.

    If your rifles fill valve is stuck closed it should act like a dead head and build psi in the line fast – no more than 15 pumps w/any hose-.

    So last attempt gun was at 1,000psi ( gauge good?) so you hooked it up, pumped a bit and the pump gauge read?

     

    John

     

     

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    Scrufhunter
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    did you open the bleed screw on the pump and release the air in the pump line before placing it on the the gun? then close it before trying to refill?

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    ironlion269
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    @spysir and @scrufhunter, my rifle's gauge was consistent with the pump's gauge the first two times I was able to fill using the pump.  I have bled off the excess air from the pump each time I've detached the hose from the gun, then closed the bleed valve.  The pump has been fully emptied prior to each attempt to fill the gun.

    Others in the thread have assured me that the Foster fitting looks OK (though it looks very irregular to me, but I'm no engineer) but I've only pulled the fitting off and given it a rookie's cursory examination.  Sounds to me like I need to go deeper by disassembling the fitting to check the valve there.  Heck, I don't even know if there's a secondary valve I need to examine further into the reservoir – @spysir, you caught me on that one and I am guessing there's nothing beyond the outer fitting that could be causing this problem.

    I have my work cut out for me based on all y'all's input.  I'll post an update when I know more.

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    Crusher
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    It looks weird to me. None of my foster fitings have anything like that in them. Could that possible be a piece of the filter from the pump?

    Crusher

     

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    EDgunWest
    Dealer
    Dealer

    I have run into this issue with foster fittings.  I have one piece Edgun probes and the 1/8 BSPP/ male foster fitting for guns I sell.  I have had a percentage of them in the past not fit.  Some female fill whips would not have a problem while others would not lock on fittings that looked perfectly in spec.  The I have now had them all made slightly "sloppy" and had not had a problem.  You can solve the problem by sanding the top of the male collar on the foster. Just keep polishing it until it locks.  It won't take much, go slow, remember you can always take more metal off but you can't put it back.

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    ironlion269
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    @crusher and @edgunwest, thanks for chiming in on this issue.  As I said in the OP, the look of the fitting's top/end seems off to me but I have no experience with such things.  I just thought the valve inlet should be regular in its surface; as my photos show, my fitting is anything but.  Polishing it down (very, very carefully) to get a smoother surface is something I am confident I can do.  Reading elsewhere recommends cleaning off the black crud (no other term fits) that coats the grooves on the reservoir side of the fitting and using Teflon tape to seal the fitting.  Again, all done very, very carefully so as to avoid damaging the grooves and not impeding the valve with excess tape on the reservoir side.  On one hand, I'm frustrated to have to do all this so I can shoot a gun that I've been working to own for a year now.  On the other hand, this situation will give me a great deal more confidence in maintaining my gun and pump down the road.  On the whole, I'd rather gain the hard-won experience and be that much more capable as a gun owner and mentor to anyone coming up behind me.  But it sucks to go another day without that sweet ping in my ear and smack from downrange.

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    Crusher
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    You said "After just four rounds of refilling my new Marauder's tank I am unable to get the gun to accept any air. My last attempt had the gun at 1000 psi and it still wouldn't allow any air to pass the fitting. I am using a factory-new Benjamin pump but it is the Foster fitting on the rifle that has me concerned. Does the fitting in the attached photos look defective?"

    So you are saying the female won't stay connected?  I was wondering what that crap in in the end of the male. None of mine have that.

     

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    Scrufhunter
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    comparing it to mine    the screen is supposed to be there   but mine is pushed down further     you could either send it for warrenty or just push the screen down a little or remove it.   its purpose is to act like a filter to help keep junk n gunk out of the resivour and eventually the valve   look inside the female end on the pump and make sure the o ring is seated

    becareful with teflon tape   if a piece ends up in the valve    then u gotta take the whole damn thing apart to get out….you will know if it happens from the continous hiss from the breech……leak

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    Saltlake58
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    New fill nipple / valve from Crosman is only about $20.  You need to get the fill nipple, degass the gun, then it's a straight forward unscrew and replace.  Lots of videos on YouTube.  My Marauder doesn't have the filter, but the nipple sitting in the drawer, about ready to replace the original, does have the filter.  Looks more "evenly" distributed across the opening, but other than that, it looks the same.  Maybe I'll get that repair done next week, maybe not.  So much to do!

     

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    ironlion269
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    Update on the issue: with the Mrod still degassed I pulled the fill fitting off the end of the gun's reservoir and cleaned it thoroughly.  Put the fitting back together and on the rifle.

    Next I printed out the complete Sun Optics guide to servicing the HPA pump that Benjamin brands and sells.  This is the hand pump I purchased and then had fail on the third round of airing up my gun.  Pulled the whole pump apart per the directions from Sun Optics – must say that the step-by-step instructions together with the photo illustrations AND list of O-ring sizes for each seal really make the process doable.

    Unfortunately, three complete rebuilds later (just to be sure I didn't skip any parts or end up having clogged a valve) and I discover that even a little back-pressure on the pump outlet causes the air to escape the pump through the inlet valve!  I've installed a desiccation kit on the pump and actually watched as the silicon beads were blown back UP the container with each downstroke of the pump.  As a result my pump is all shiny and slick and as useful as a paper weight when it comes to filling up the Mrod.

    I'd be really bummed with myself right now if I thought I'd screwed up my pump all on my own… but the pump Failed (with a capital "F") before I ever did the first thing to clean it up, much less tear it down for a complete overhaul.  Calling Sun Optics tomorrow to report an incident for support and determine next steps.  Obviously sending in the pump seems like a no-brainer but that just means more stinkin' time with no air source for Elliot.  Yes, I've named the gun Elliot.  Bonus points if you can figure out the connection.

    Still and all, I've had Elliot for over a week now and only have ~120 pellets through it.  I have two magazines filled with H&N Barracuda pellets sitting on my workbench, waiting for further testing and tweaking of the gun.  Just sitting.  Galls me every time I look at 'em.  I must learn to have patience… right now!

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    steve-l
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    Member

    Those Foster fittings one-way function depends on air pressure in the tank to seal. There is a simple cylindrical plug with a tiny O-ring on it just pressed into the fitting bore. To take it apart, all you need is a pin punch applied to the filter and push. Piece of cake! Now here's the tricky bit. Most of these have 1/8 BSPP (British Standard Pipe Parallel) threads, but not all. BSP threads use a 55 degree thread form, not 60 like metric or our National Standard threads, that's first. Secondly, these BSPP fittings seal on the base with a nylon washer, not on the threads with tape or sealant. If they are over torqued when assembling, the nylon washer will crush and squish out into the center hole interfering with the foster fitting's slug's motion potentially blocking the fitting from opening. So be careful tightening these fittings! By design, this fitting will not flow air without a positive pressure differential between the input and output side of the fitting. When the pressure in the tank is greater than at the input side, the tank pressure pushes the tiny slug through the fitting bore until the slug contacts the internal machined shoulder stopping its travel…….just sayin!

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    Scrufhunter
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    Elliot from ET?

    Phone home

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    ironlion269
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    @scrufhunter, good grouping but not on the bull's eye.  think of a lesser well known movie reference.

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    Scrufhunter
    Participant
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    Sam Elliot?

    The Quick and the Dead?

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