Fix your Benjamin or Sheridan pneumatic at home!

by B.B. Pelletier

I was flabbergasted when I saw what I’m going to write about today. An actual kit to repair a multi-pump pneumatic is a pretty rare thing. In over 40 years that I’ve been involved with them, I’ve never seen a home repair kit.

You don’t have to depend on dealers to get your spare parts
While writing about the Benjamin 392/397 rifles yesterday, I was shocked to see a repair kit offered for them! This represents a 180-degree turnaround in policy from the old days, when you couldn’t get these parts unless you were a dealer or a company-authorized repair station. It makes me wonder whether this is 2005 or 1905!

The new kit is good for the Benjamin 392, Benjamin 397, Sheridan Blue Streak and Sheridan Silver Streak. Who could ask for anything more?

No directions, so you have to know what you’re doing!
Pyramyd Air put this kit together for you but there are no instructions, so you have to be handy or know what you are doing. Many of you are, undoubtedly, qualified. But, if you think you’re not, listen to your instinct. It would be better if you had an old, non-collectible airgun that you can risk ruining to test your fix-it skills. Whatever you do, don’t practice on your good Blue Streak!

This may work for you whether you’re handy or not!
If you struggle to replace the batteries in a garage door opener, this kit may not work for you. There’s still a benefit, since people who are technologically challenged often have good friends who can fix anything (they need them!). Buy the kit so your good buddy can install it for you! It’s a win-win situation regardless of your own capabilities or interests.

Buy cheap, broken-down guns & repair them yourself!
Knowing this kit is available opens up a lot of possibilities to buy guns at flea markets and pawn shops. So what if they don’t work when you get them? You can rebuild them in short order. I’ll certainly be a lot more aggressive when looking for older guns that match up with this repair kit.

These parts may not work on older guns
Remember that the Benjamin 390-series rifles have been around since 1992, and the Blue and Silver Streaks have been with us since 1949! The parts in this kit are probably not going to fit the older versions of these guns, so think about that before you take the plunge.

A second repair kit is also available!
Lest you think I’ve overlooked it, Pyramyd also sells a repair kit for the IZH 46 and 46M. The kit has seals only, but that’s all the single-stroke pneumatic needs. If you’ve used this kit, I’d appreciate hearing from you.

Are instructions next?
These two kits are going to generate a demand for instructions. While some customers will sail through the job without stopping, much of American know-how has gone south. As cars, TVs and blenders became more disposable and less repairable over the decades, two generations of Americans have grown up without doing their own simple repairs – unless they had a detailed manual (or even a video!). They expect such support and are often shocked if it isn’t instantly available, as in, “Where’s the web page?”

For both repair kits, you will need some good silicone oil, and I recommend Crosman Pellgunoil. Buy it when you order your kit so you don’t forget. Let me know how the Benjamin Sheridan repair kit works for you.

15 Responses to “Fix your Benjamin or Sheridan pneumatic at home!”

  • Anonymous Says:

    I think i over pumped my benjamin 392. it is fairly new and will no longer hold air since i over pumped it. Will the replacement seal kit sold on pyramid air fix this or is there anything else i will need? i really want to get this gun fixed and i will send it into a shop if need be. Thanks,

  • B.B. Pelletier Says:

    You keep asking the same question and I have answered it many times. Are you forgetting where you are asking it?

    Over-pumping WILL NOT cause seal failure. But failing to oil the gun will. Have you oiled the gun with Crosman Pellgunoil, as I have asked in the past?

    It really makes a difference.

    The repair kit is not simple to install. Unless you are very handy with tools I recommend you send the gun in to Pyramyd Air for repair, but of course call them before you send the gun.

    B.B.

  • Anonymous Says:

    im really sorry about the multiple posts. i saved the links i posted at but could not find them again. Thank you for replying still. i have always been diligent about oiling the gun and have used the oil you suggested since i first got the gun so i know that no oil is not the problem. i do know that i overpumped the gun and that it will no longer hold air. what kind of damage have i cause to my gun if the seals are still ok?

    Thank you for the replies and sorry about the confusion.

    • B.B. Pelletier Says:

      I think you may have gotten a piece of dirt on one of the seals. Sometimes this can be fixed by just shooting the gun several times.

      Are you able to pump the gun and shoot it, or does it leak down as fast as you pump it?

      B.B.

  • Anonymous Says:

    As quickly as i pump the gun it loses air so i can not shoot it off. This started right after i accidentally over pumped it.

  • Fred PRoNJ Says:

    Anonymous,

    BB is on his way to Virginia right now. Let me ask a question – does it matter if the gun is cocked or not when you pump it? If not, try cocking and then pump and if that doesn’t work, cock and fire it several time (perhaps the valve is stuck open) and see if that makes a difference – that is, assuming you haven’t tried this yet. While some pneumatics require the gun to be cocked when trying to pressurize the first time, this particular air rifle doesn’t fall into this class but I figure you have nothing to lose other than time.

    Good Luck.

    Fred PRoNJ

  • Anonymous Says:

    I will try this out. Im quite confused though because it seems like the both of you are saying that even after though i over pumped my gun it should still work? i always thought that if i over pumped it would break something inside the gun like the seals or something.

    • Fred PRoNJ Says:

      What typically happens with over-pumping this rifle is either the valve mechanism releases excess air pressure within the rifle (the spring that keeps the valve closed is overpowered by the air pressure) or the firing valve becomes locked from over pressure, causing a less than optimum release of the air pressure when the hammer strikes the firing valve. You can tell when you overpump it if you fire the rifle and then re-cock it and, without pumping, shoot again and release more air pressure. This is referred to as valve lock and is common with PCP’s or pre-charged pneumatics that have been over-filled. I’m hoping that your firing valve or some other release mechanism in the rifle is perhaps stuck open which doesn’t allow the rifle to pressurize. Other than this, I don’t believe you can damage your rifle by over-pumping it. I’ve only pumped my Benjamin 397 8 times and decided the effort was not worth the slight extra velocity for those two extra pumps.

      Fred PRoNJ

    • Wulfraed Says:

      There should be three points that are air-tight in a multipump model.

      The pump head (which may be o-ring, synthetic cup, or leather cup). The only way I see overpumping damaging these is if 1) there is no oil on them and 2) there is a sharp edge somewhere in the mechanism, since higher pressure would push the material into making a tighter seal.

      There is a spring-loaded valve between the pump and reservoir. When the pressure on the pump-side is greater than the pressure inside the reservoir + the pressure of the spring, the valve will open and let a puff of air into the reservoir until they equalize and the spring closes that valve. If this valve is stuck open, then the pressure goes both ways — you close the pump and air goes into the reservoir, let go of the pump and the air in the reservoir will push back out, opening the pump handle.

      Then there is the firing valve. Depending upon design, this valve may stay open until the bolt is cocked (both my Daisy 717 and the Baikal 46 — both single stroke types where the pump IS the reservoir, so no intermediate valve — are this type, if you don’t open/cock the bolt the air just whooshes back and forth). This valve is normally held closed by a small spring and by the pressure in the reservoir — until the hammer/striker hits it on the nose, popping it open to let the air out. If the pressure in the reservoir is too high, it is possible the hammer can’t open the valve enough to really fire a pellet — valve lock, the internal pressure has “locked” the valve shut. Repeated cocking and firing /may/ let small puffs of air out until you drop below the critical lock point.

      But you state you hear air moving… That seems more indicative of the firing valve being stuck open. Air goes from the pump through the intermediate valve, through the open firing valve and up the barrel.

      If you hold a finger on the end of the muzzle and pump the action, do you feel pressure in the barrel? That would indicate firing valve stuck open. As with valve lock, try cocking and firing a few times to see if the valve will loosen and close. And make sure you have put a few drops of oil on the pump head and any o-rings you can find.

  • Anonymous Says:

    Thank you all for the great replies. Sounds like i may be able to figure this problem out. i shall report back with my progress when i get a chance to really try out those options.

  • Anonymous Says:

    sorry i took so long to follow up. I did as Wulfraed said and indeed i believe the valve is stuck open because i feel air moving out of the muzzle when i pump it. Are there any other tricks to try and get the valve to close again?

    Nick

    • Wulfraed Says:

      {I’m working on hypothesis here; and I haven’t reread the entire sequence}

      You have tried with the bolt opened? As I mentioned, my single pump pneumatic doesn’t close the firing valve until you bring the bolt all the way back.

    • B.B. Pelletier Says:

      Nick,

      When an airgun dumps air like this the valve isn’t stuck open. The valve return spring won’t permit that. You most likely have a broken o-ring or a deep nick on the valve face. Your gun need to be rebuilt.

      B.B.

  • Anonymous Says:

    i tried with the bolt open and i can feel the air moving out of the opened breech.

  • Wulfraed Says:

    Okay… we’ve reached the limit of diagnosing on-line… I think it’s time for surgery…

    Either a repair shop, or home take-down (if it is just blown seals, and one can find the assembly instructions and parts list)

    Well, one last question (again, it may be up in the thread somewhere) — ignoring the air, does opening/closing the bolt, and then pulling trigger (safety off) result a good sound. That would at least ensure that the trigger/sear, and cocking, mechanism is working — and the problem should be in the various valve seals.

    But I’m fairly convinced it is the seals (o-rings with luck, that can be found locally).

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