Disconnect the chain from the lever,and using a pair of pliers turn the nut on the lever counter clockwise. These threads are reverse from the norm.
Where is it leaking ? Flapper in the tank, replace flapper. Between tank and bowl, separate and replace the seal. Toilet to floor. Replace the wax ring under the toilet, making sure it is thick enough to form a seal and the bolts are installed correctly and holding the toilet down.
That's how it is supposed to work. Pulling the lever lifts the flapper in the tank which lets water into the bowl.
Assuming you have a regular tank toilet with a ball float and rubber flap and that the water is turned on and the tank is filling, the most common cause of a toilet not flushing is a broken or detached chain that runs from the handle lever to te rubber flap that keeps the water in the tank.
They are usually about 24-26 inches high
You replace the toilet as a whole item. You cannot take a tank from one type and put it on another.
Either on the underneath side of the lid or on the back of the tank inside there should be a model number. Possibly on the underneath side of the tank also.
It lifts the tank flapper /bulb connected to the Douglas Valve On a Flushometer it moves the piston assemble aside
They weaken the little plastic parts inside the tank so they break. I learned this when I had to replace the insides of my tank. The chemical in the water corrodes the plastic.
one lever in a bathroom is a toilet lever hope that helps:)
check that the toilet stopper has been switched on and check that the strainer inside the toilet inlet is clear of debris
The width of a toilet tank can vary in size. The average width of a toilet tank is about 18 inches.
First check to see if the valve for the water supply is turned on. If that isn't the problem you may need to replace the tank water valve, they do wear out and are not that expensive or difficult to replace.