Case 1816B Steering Issues

I bought a 1981 Case 1816B skid steer. The motor runs great, carriage and bucket cylinders operate just fine. The issue I discovered after driving it awhile is in the steering. It drives "straight" forward and reverse just fine, but any degree of turning must be done gingerly. The machine makes terrible popping sounds while it jerks into a turn. I can't jam to controls to the stops to spin in the same spot like it should. Also, one time while I was using it, the machine start to buck during a turn, bouncing diagonally back and forth. The violence of the motion was growing by the second, when I killed the main power cut-off switch to the skid steer. This stopped the action, but had it gone on a few seconds more, it would have either thrown me out of the loader or pitched over on its side. What components should I look at first? I was think #1 the Steering Control Valve and #2 the Steering Displacement Pump. Has anyone run into this type of a problem before, and can I get some guidance? Thanks, Jeff

Case 1816B Steering Issues