Rotary vane compressors each have four self-wearing carbon vanes. When these vanes become worn to a certain point they no longer catch air and you will notice a large reduction in air flow. These repair kits include four new vanes, a new gasket and two new black, internal air filters. Rotary vane compressors can be rebuilt in 20-30 minutes using common tools.
1/4 HP Rotary Valae Repair Kit
Has good instructions, easy to install and only takes a few minutes to install. I have had my pump since 2012 and this is the second kit I've put in. For me the vanes seem to last around 3 years before they wear down and air flow drops off or they break. Overall a good product.