Quote Originally Posted by hammy View Post
Originally the piston on this rifle was seized in and it wouldn't cock at all.
Stripped it and lubed it up as there was no lube on it.
Now when cocking the trigger will cock but it won't hold the piston.
The small spring that pushes down on the sear is still there despite it trying to escape across the room on disassembly .
There is a small bit of wear on the sear but it doesn't look too bad and no wear on piston rod.

Any ideas ?
Firstly, take it apart and just try pushing the piston rod into the trigger housing and see if it engages ok and holds. If it does, it suggests the trigger/sear is ok---------if not it would suggest that the sear/trigger is worn or needs adjusting, or the trigger spring has jumped and is stopping the sear and trigger engaging. Then. try it without the mainspring in and the cocking arm removed and see if the piston engages when you slide it back with a screwdriver or rod. Then, if it does, the sear should hold the piston as you try to push the piston forwards. Then refit the cocking arm (as these sometimes bend a fraction) and see if it cocks then. If it doesn't then it could be the cocking arm bent or the piston worn where the cocking arm pushes on.
If it does cock and hold then, it could be the mainspring is too long and coil bound.
I had one bugger ( the first one I saw) that the sear was broken on but they had dressed it up so it didn't look broken.