I’ve replaced the seals in my fortitude and can say without reservation it was my least favorite Crosman to replace seals in. The holes are all so sharp it is very easy to slice the o rings putting it back together. I’ll go one further....it’s just about a guarantee you’ll slice one getting the valve back in, so have a few extras on hand and also it’s well worthwhile to try to smooth out the sharp edges of the holes the o rings have to go past. Also use a small wooden dowel rod at each hole you pass to push the o ring down so it doesn’t get cut.
If you are still under warranty and don’t have a burning desire to get very intimate with your Fortitude then I would advise sending it back for more service.