How to replacing a flush handle?
When you press down on the flush lever handle, it stick-and you have to pull it back up.
Stiff flush levers are usually heavily corroded, while loose ones are probably broken. You may be able to free a sticking lever using a few drops of penetrating oil, but replacement is a good idea, especially considering how little a new one costs. Old lever handles also begin shedding their chrome or brass plating and look ugly.
There's nothing difficult about this repair, but in this case knowledge works better than leverage; you should know that the hex nut holding a flush lever assembly to the tank uses left-hand threads.( that's right, the threads are backward. To loosen this nut, turn it clockwise rather than the usual counterclockwise. If the nut is too corroded to break free, cut the assembly apart with a hacksaw.
Your new lever and handle will likely come in one piece, with the fastening nut the only other component. the lever may be metal or plastic, while the handle will probably be chrome- or brass-plated metal. Snake the lever through the tank hole; then slide the nut over the lever, and screw it onto its threads. Finally, connect the flapper chain or lift wire.