eheim filter support please

My Eheim canister priming support is not sucking water, hard to press down
and very sloooow to come back up. Have to actually pull back up on that
primer button.

I have a little packet of grease that was included in the box but just where
to grease is a mystery. I'm leery of using this grease also, must be a
petroleum product of some kind I presume?

Any info. would be appreciated from anyone experienced with Eheim canister
filters thanks, John