What tractor are you running the Redball with. I had a Red ball sprayer new back in 2001 and had it on a new tractor at the time  (MX 210 I think) with the newer pressure compensated hydraulic system. If you had the flow on the tractor turned up too high it would do funny things and not work. Problem if you had the flow too high hydraulic pressure on would go to 3000 psi and the valves cannot handle that much pressure and work properly. If I turned the flow down every thing worked properly. Hope this helps as is a easy fix if you remember to turn flow down.