I have a Crosman Mark II and I ordered a kit with power valve and the 2nd o ring I tried to slip on busted. I am not the type for rebuidling one of these. Nice looking air pistol. I am frustrated. listed it on ebay. free pickup in 21087 if you are interested.
https://www.ebay.com/itm/173182365517?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1558.l2649
https://www.ebay.com/itm/173182365517?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1558.l2649