Hakko and Matala air pumps are the standard for most koi pond and water garden aeration needs.
The rebuild diaphragm kits are simple to install. However, like any other machine with constantly moving parts, there is a possibility for things to wear out over time.
If your pump is working yet not pushing any air out it is most likely that your diaphragm needs to be replaced.
Check that the number of air diffusers is sufficient to handle the air output of your Hakko pump. Too few diffusers will produce excess back pressure, make sure that the air delivery tube is large diameter and no kinking is occurring. Also ensure to examine your air diffusers for clogging.
Occasional diaphragm replacements will increase the air pumps life expectancy and its overall performance. Diaphragm replacement will increase performance and longevity of the air pump.