The toilet flushing system is a simple mechanical design, yet is the first step in a properly operating toilet. The toilet is rendered nearly useless if the toilet flush is broken. While there may be more obvious solutions to a broken toilet flush, such as a broken flushing handle, other problems require a keen eye for inspection. Regardless, you can fix the toilet flush by repairing or replacing small parts, saving yourself the trouble of calling a plumber.
Remove the tank lid and place it on top of a towel. Doing so will prevent any chipping on the bottom of the lid.
Search for the ballcock, which lets the fill valve know when to stop. If the ballcock has a hole in it or it's broken off, your fill valve will not open to let water into your tank. Replace as necessary.
Jiggle the flushing handle, then move it up and down slowly. Observe its pivot. If the handle moves loosely, you may need to replace the handle's hardware.
Examine the flushing lever and replace it if there is any corrosion or it looks worn. Some signs of wear include metal handles bending when you move the flush handle.
Look at the flushing chain's connecting points on the flushing lever and the flapper, respectively. They should be firmly attached with no breaks or obvious corrosion.
Check the chain's length to see if it's too long or too short. Too short of a chain will keep the flapper valve open, while too long of a chain won't lift the flapper up. Adjust as necessary.
Inspect the flapper valve and gasket for any damage, wear and tear, or deposits between the flushing tube and the gasket. Clean any deposits and replace the flapper or gasket if either has any damage.