Hi Bob,
Have you managed to remove the pins?
If so then you need to pull the gripper bow forward to remove the complete assembly.
Strip it all down and wash all the parts, dry and inspect the all nylon gears for wear also that the back of the gripper bow that the two tabs have not broken off or are worn, if they are this will effect the turning of the gripper bow in operation.
Please let us know how you get on.
Regards
Alan
Alan Hood
ami-man
UK