The piston rings provide compression in an air compressor pump by providing the seal in between the cylinder wall and the piston. In an oil-bath pump, there are usually two compression rings and one oil (scraper) ring to keep oil from passing the piston and into the head. In an oil-free pump, the piston is Teflon-coated and doesn’t require lubrication. If your pump is pulling oil into the head or if compression is very low (oil-bath pumps), replace the rings. If your pump isn’t pressurizing or if the piston ring is damaged along the outer perimeter (oil-free pumps), replace it. Also replace the cylinder sleeve when replacing the compression ring (oil-free pumps).
This item fits the following models:
3-Nailer Combo Kit w/ Accessories
3-Nailer Combo Kit
1/4" x 50 Ft Noodle Air Hose with Coupler and Plug