My 1077 came out of storage and was really low on power. Since it had been a long while since any maintenance was done, I decided to clean it out and reseal it.
I discovered that there are 4 editions of the 1077 and based on the parts in mine, I have the first edition. I cleaned everything (screen in the fill assy was filthy) thoroughly and set about resealing it. The fill screen is omitted in newer editions but I elected to keep mine. I got all the right parts from Crosman and got it all back together with no issues.
However, I have a stubborn leak at the valve assembly I cannot figure out.
I cannot tell if it is the valve leaking or the tube to valve joint. When I put anew CO2 cart in and tighten down the piercing screw, I hear a loud steady hiss of escaping gas. Rifle shoots like a house on fire till the gas is gone. Usually only takes three or four minutes to leak dry. I have disassembled and reassembled several times trying to figure it out.
What can I do to diagnose the issue and figure out where the problem is and then how to fix it?
Looking for any suggestions from those who have gone before me.
can you gas that rifle up with the side cover off safely I looked at a few videos and the parts diagrams last night and thought that looking at the gut with the cover off is what I would do maybe tape the valve in place but your leak would be found, the how to fix is another store but my guess is a damaged o-ring
The earlier version of this gun has a different valve and was more reliable. The valve with the brass end that screws in is the one you want. The later version is held together with a clip and is prone to leaking.
Thanks for your suggestions. I do have the early valve and as you mentioned it has been rock solid till I started messing with it. I bought the rifle used in the late 90's just before ebay quit allowing pellet gun auctions. I did not reseal it then and it was a great shooter till last summer.
I tried leaving the receiver cover off and gassing it up. Twice have blown out all the gas as it came apart in an unplanned rapid disassembly to borrow a Tesla phrase.
I bought new seals for the transfer tube and will give it another shot. I did wonder if I tightened the brass end plug tight enough. It was deforming the seal as I tightened it and I was not sure how tight to make it or how much seal deformation was correct.
The fact that Crosman changed the valve design is what keeps me from just buying a new 1077. The less expensive valve design does not appeal at all.
Sounds like a common problem I had with the 160 Pellgun Variant one. You have to polish the exhaust valve stem. At least with Green Scotchbrite pad. The lube it with some Pellgun Oil upon reassembly. That fixed mine. The valve sticks open and all the gas leaks out. Working the bolt sometimes helps, but not often. I also use the Scotchbrite green pads to polish commutators on electric motor armatures. Works real well. I also like the white 90 durometer seals on the gas tube cap and front seal on the valve assembly. The hold gas way better. So well, in fact, that those are what's in the mac1 seal kits. I love'em!