Crosman 1377 rear cocker

[techmaven]

I just bought a reseal kit for my 1377 that I bought maybe 25 years ago..hadn't used it for a while and upon picking it up again, it had no compression when pumping. I put several drops of pellgun  oil on the pump assembly and after a half hour or so, it was making pressure...that was subsequently leaking out at the breech. so, while looking for a tear down vid on youtube, I was pumping and listening to the air seeping away...All of a sudden, the "dang" thing is holding pressure with not a hint of leakage.

I guess the seals finally got some of that pump cup oil?...Dang...lol

[Gertrude]

The leaking from the breech/barrel is due to the poppet not seating completely. Give it 6 or 8 pumps and fire it a few times without a pellet. (This will not harm anything). This will cycle the poppet and help it to reseat .

[techmaven]

I suppose that's what happened...Thanks for the verification! Maybe my 40y/o 760 can do the same thing..haha