quickmaster 46 plate clamp

The center part of the plate clamp on our quickmaster 46 is frozen shut. Any suggestions on what our next step is? We are not sure if the whole clamp needs to be removed from the cylinder or not. Any help at all would be appreciated since our location requires us to fly a heidelberg mechanic up from Calif. to Prosser, WA.

 

QM 46 plate clamps are a pain in the ***. Use plenty of WD40 and try to unfreese it.

 

Thanks - I've tried that with no luck - hammer didn't work either - guess I might have to try to take it apart