2 color printmaster gto 52

Hi, im Wondering what I can do when my reversing Drum grippers don't want to close and grip my stock? I've greased everything I can think of and if I let my machine sit overnight it will run a few thousand sheets yhe next day but then will go back to my reversing Drum grippers not closing so then my stock jams up! Thank for any advice in advance.

 

hello can you show us some picture given that there is the turning drum and the regrouping drum thank you very much