Pistons are cylindrical parts that fit inside a larger cylinder. Pistons move under fluid pressure of a reciprocating engine and can either displace or compress fluids such as in pumps and compressors. Piston rings are located between the piston and cylinder. Piston rings help engines operate efficiently and have several major functions, including creation of minimum oil lubrication film, sealing compression gas, and heat transfer in addition to piston support within the cylinder.
Put on safety gloves. Turn off the engine or power on the device where the piston ring is to minimise potential injury.
Mix equal parts brake cleaner and penetrating oil.
Wipe out the interior cylinder walls with a rag.
Hammer one end of the copper wire until it is flattened paper thin, like a knife tip. Use this to penetrate the grime between the piston rings, piston and cylinder walls. Cleaning out the grime and dirt in these areas are important in order to let the fluid soak through.
Pour vinegar into the cylinder until it covers the piston. Add the penetrating oil and brake cleaner mixture and use the copper flat tip to mix and stir the fluids around the piston and cylinder.
Let the mixture sit in the cylinder for a period of time. Several hours up to about one week is a good time to let the fluids soak and free the piston ring.
Repeat Steps 5 and 6 if the piston ring is still stuck. Take your piston to a professional if these steps are not successful.