If your lever is broken you usually need to replace the flush valve seal to make it easier to flush
Genuine Mansfield Float Ball Replaces Current Black And Older white or blue Float Balls
so the first time you put the screw into a new stem it may be a little difficult
MANSFIELD GENUINE 2916-1112 RIGID FLUSH VALVE
meaning you will turn it to the right to loosen
Mansfield / Mancessa Flapper 630-0173 MPP216 If your lever is brokenMansfield Flapper fits tank models 172, 173, 174, 392, 395, 4320, 4321, and is the replacement flapper for Mancessa toilets with the rubber strap instead of a chain. Measures 3" across. 006300173, 6300173 Mansfield Mancessa Flapper 630 0173. The package has a card to let you know which insert to use in your Mansfield toilet model. It is flexible rubber and is easily installed buy putting the rubber hoops over the "ears" on the side of the flush valve.