Where is the pressure stored in a Benji 392?

Where is the pressure stored in a Benji 392?

Joined: May 31st, 2002, 8:52 am

April 9th, 2012, 11:32 pm #1

I'm sitting here tonight looking at a non working Benji. It has been holding air fine for three years now....just no way to exhaust it. The bolt cocks the hammer and the trigger releases it, but nothing happens but the thunk of hammer falling(maybe not hard enough?).
I took it out of th3e stock figuring I have nothing to loose by taking it apart and got to thinking "that's got to be considerable pressure somewhere" and looking at the next step taking it apart and there are two phillips screws holding the trigger assembly on beside the nut on the bottom of the tube. If those two screws come out in a pressurized gun would this end plug become a projectile?
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Joined: May 12th, 2001, 1:29 pm

April 9th, 2012, 11:37 pm #2

That's a self-contained unit that even can be completely removed from the gun without depressurizing it.

Steve
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Joined: September 21st, 2011, 10:19 pm

April 10th, 2012, 12:06 am #3

I'm sitting here tonight looking at a non working Benji. It has been holding air fine for three years now....just no way to exhaust it. The bolt cocks the hammer and the trigger releases it, but nothing happens but the thunk of hammer falling(maybe not hard enough?).
I took it out of th3e stock figuring I have nothing to loose by taking it apart and got to thinking "that's got to be considerable pressure somewhere" and looking at the next step taking it apart and there are two phillips screws holding the trigger assembly on beside the nut on the bottom of the tube. If those two screws come out in a pressurized gun would this end plug become a projectile?
I got curious, so I went a searchin'

Take a look here for a parts diagram that may be of some help.

http://www.crosman.com/cs/manuals/benjamin-and-sheridan

The 392 is near the bottom of the page.

---Scott.
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Joined: May 31st, 2002, 8:52 am

April 10th, 2012, 1:47 am #4

That's a self-contained unit that even can be completely removed from the gun without depressurizing it.

Steve
Lock it in a vise and hit the stem with a hammer? The gun was in a closet. For a couple of years and I had forgotten the problem and opened the lever once then and just tonight(about a year later) and both times was like a maximum stroke.
Can the valve really hold pressure that long ? If it were built up to say 10 strokes or more might there be too much pressure for the hammer strike to overcome?
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Joined: May 12th, 2001, 1:29 pm

April 10th, 2012, 4:42 am #5

...with a hammer (gently at first of course, then gradually more forcefully) should release it. You can do this best and most conveniently while the valve is still in the gun.

It's also possible to release pressure by tapping the checkvalve with a pin punch inserted though the intake hole, if the firing valve has failed in a way that prevents it from opening even when the stem is depressed. That's possible and sometimes happens if the rubber seat slips out of the stem head.

If all else fails, you can also (carefully!) unscrew the valve halves. The seal "should" break and the air escape before anything violent happens.

"Should" that is. So if you take this route, just be very sure nothing expensive is in harm's way - just in case.

Steve
Last edited by pneuguy on April 10th, 2012, 4:52 am, edited 1 time in total.
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Joined: May 31st, 2002, 8:52 am

April 10th, 2012, 12:06 pm #6

After I get the trigger module and rear "cap" off will the rest of getting to alve be evident? As long as no parts go flying or drop and roll out of sight I should be capable of putting it back together in the proper order.
I'm going to revisit the HDD install pictures to see how to get to it. Is it possible that it could be binding and slowing the hammer travel? I don't dry fire(without a charge) my pumpers but tried one of my rocker Sheridans with one stroke in it and the hammer hitting home felt quicker and harder.
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