If the surface of Bitzer 4TC piston has obvious burns, nicks, or obvious protrusions along the axial direction, it should be replaced with a new one. Use an outside micrometer to measure the diameter of the piston pin. Generally, when the radial wear is less than 0.05 mm, it can be ground to a smaller size and then repaired by chrome plating or iron plating; the piston pin can also be heated to restore its size by swelling. When the radial wear is greater than 0.05 mm, it is generally replaced.

     In order to prevent the piston pin from moving and scratching the cylinder wall in the pin hole, elastic lock rings are installed at both ends of the piston pin. Under normal circumstances, after the piston pin retaining ring is used once, it should be replaced when it is assembled again. If you don’t have any accessories to be replaced, you can judge whether to replace them by observing the diameter of the retaining ring in the free state and whether it is deformed. If the diameter in the free state is greater than the diameter of the piston pin hole by more than 3 mm, and there is no obvious For defects such as deformation and extrusion scars, you can continue to use the Bitzer 4TC piston, otherwise it should be replaced.