Gast 81R Rebuild Kit for Twin Cylinder Rocking Piston Oil less Pumps This Aftermarket kit will Rebuild the top end of our compressor and will correct low pressure issues or no pressure. If your pump is failing due to low or no psi this kit will correct it. Condition: New Kit Includes: AT329 CUP seals, sleeve O-rings, Head Gaskets, & 4 x Flapper valves. - DOES NOT Come with sleeves. They are no longer made or available for this model. These can usually be cleaned with a scotch pad and alcohol or flipped over. This kit fits pumps with a cylinder sleeve ID of approximately 63.60 mm. If you have a different dimension please let us know your size so we can point you to the correct kit. Fits 81R640-P101-H302CX 81R640-P101-H311CX