Bought a 1998 Sheridan C9A at a flea market last weekend. It looked neglected but was all there except for the three screws in the rear sight. Pump linkage was tight and no barrel separation. No pump pressure at all, so I got it for $40.00. I got it home, cleaned out the paint overspray in the barrel, and lubed the pump cup with power steering fluid w/stop leak. After several pump and shoot cycles over 10 minutes, it held two pumps and then 5 pumps overnight! I got some sight screws at the hardware store, cleaned up the wood and metal and now it looks only slightly used.
I fired several rounds at 15 yards and found the rifle shooting high even with the rear sight adjusted to the lowest position. I searched the forum but found no solution to the problem I was comfortable with. My solution was to put a "speed nut"( a spring steel, sheet metal clip that acts like a nut used to connect sheet metal panels. Used extensively on automobiles, cloths dryers etc.) over the front sight to raise it about 1/8". I had to grind some off to make it fit and then epoxied it in place. Works well and looks good. It can be removed with a heat gun if I ever come up with a more elegant arrangement.