Crosman 1400 Discharges When Pumping

[Starbright]

I took it apart again and was going to replace the quad seal but I noted a minute piece of wood inside which is probably the remains of a toothpick that i used to install the quad seal last time.  Of course, I took it out and I think I'll put the Crosman back together in the AM thinking that may have been the problem of air leakage.

[Blowpipe Sam]

I'm puzzled, what is the valve sealing cap flat on the surface that contacts the sear pin?  I've looked at diagrams of the 1400 and it looks like and I may be wrong the trigger assembly?  Dang, I hate to change the quad seal agin, it'll be the 3rd time.  I have an extra seal kit that I can steal it out of and if that is the culprit, maybe it'll do the job of stopping the leak.

The valve cap is the part that the quad seal goes into. The flat surface is the inside surface of the quad seal.

Actually I was wondering if this thing is a bit more Frankenstein than we had thought.  The 760 valve cap is different from the 1400 but the valve is identical.  I thought it might be a 760 cap was mistakenly substituted by the builder.

 If the nipple that the quad seal fits over is distorted (ovalized or scratched) it may cause the cap to leak.  Make sure you're cleaning all of the old quad seal out of the groove when you replace it.  Use a tooth pick to install the new seal so you don't mar it.  That's all I got.  Hope it helps you.

[Starbright]

I put it back together and so far it isn't leaking.  The trigger assembly had a 1/8" nut used for a spacer since there would be a gap b etween it and the barrel and I found that it had some "slop" vertically so I configured a washer to fit over the tube pin plug and it is snug now.  I'll leave it pumpped up all night and check it in the AM and report.

[Starbright]

Welp, it's holding air, I guess the piece of wood was the sole problem.  Thanks to all of you that helped me solve the problem.

[Back_Roads]

 Good to see your perseverance paid off Enjoy shooting it now