hand primer on 8560 Mahindra stuck

[HFarm]

I have an 8560 Mahindra which I can not free up the hand primer pump to prime the injector pump. It is the type that you turn a knob to unscrew the primer and then work it up and down to prime the pump after changing oil filters etc.. You can unscrew the knob, but can not lift it up. Anyone else have this problem? Any suggestions?

Thanks