1377 rebuild

[badduck]

My friend gave me a new 1377 original serial # 281060588
had it holding air 3 times up to 10 pumps after I disassembled and reassembled ,then it quit holding air again
So my question is it worth rebuilding a $60 gun or should i put it up for sale so someone doing an original rebuild can use the parts its in new condition 
Its in the original box with original paperwork perfect shape

[rangerfredbob]

The old rear cockers aren't bad guns, it sounds like it just needs some love... current parts will get it going again. The hardest part is removing the pump pivot pin which I think at that point was a simple roll pin similar to the current ones. For parts that you would need from Crosman (their website likely still has the EVP diagrams hopefully, get the part numbers from there or I'll see about looking through my notes...) would be a pump cup, valve assembly (the assembly is cheaper than the sum of it's parts, keep the original brass valve) which I believe comes with the outer O ring, the rest should be fine. From the Crosman parts department last time I ordered a valve it was just over $6 and pump cup was $1.15 I think and I believe $4 shipping? There's a reason I stick with Crosman... You have to call them and they're closed a lot this time of year...

For fixing it, remove the pump pin, remove the grip assembly (the two screws you can see, be careful the safety spring sits against the tube, there's a small ball bearing in the trigger end of that), remove the breech which should just be the rear sight screw and the one screw you can see with the loading port slid back, keep track of the direction of the transfer port between the barrel and the valve along with it's seal. At this point the hammer should basically fall out the back of the tube and you should be left with the valve in the tube, push it out the front of the tube with a dowel or tube of some form. Getting the valve apart isn't the easiest as it likely has red loctite so you will need heat (heat gun or butane torch) and to carefully grab the two halves to turn... Reassembly is reverse...

If you aren't that handy then maybe pass it along