Top parts that can break on your Presto pressure cooker
Pressure regulator. The pressure regulator controls the pressure level inside your pressure cooker. If steam constantly escapes through the pressure regulator and prevents pressure from building up inside the pressure cooker, then you'll likely need to replace the pressure regulator.
Pressure gauge. The pressure gauge indicates the pressure level inside your pressure cooker. Replace the pressure gauge if it doesn't properly detect the steam pressure level inside the pressure cooker.
Lid gasket. Eventually, the lid seal can dry out and crack. Replace the lid seal if steam escapes through the sides of the lid when canning or cooking.
Canning rack. The canning rack holds jars above the bottom of the pressure cooker when canning. Replace the canning rack if damaged.
Troubleshooting your Presto pressure cooker when it won't build up pressure
You can't get your canning done if your pressure cooker doesn't build up pressure. Make sure you have enough water in the pressure cooker to build up pressure. Add water if needed. Make sure that the lid is properly closed. Check your owner's manual for instructions on properly sealing the lid shut if needed. Make sure the burner you're using to heat the pressure cooker is heating properly. The pressure cooker won't build up pressure if the burner isn't working. If the lid is properly closed and the burner works, check to see where steam escapes. If the lid allows steam to escape, then you'll likely need to replace the lid seal. If steam escapes from the pressure regulator, then you'll likely need to replace the pressure regulator.