the bathtub has a foot pressure crome stopper. press on it and it closes and press again it opens. a pop up stopper without the arm etc. the stopper will not close completely. I took off crome cover and there is a large round screw in center. It will not move. Should i apply some oil to losen up screw? what happens next. is this a one part drain stopper? never saw anything like this before. Do not want to apply pressure to large screw as i might break something in drain. comments please.
also what is this stopper called i cannot locate one on net. [email protected]