Just got my car on the road and found that when I turn a corner fluid is forced out of the cap. I have an R&C power rack and 89 Ford power steering pump. I have heard of a low pressure valve to lower the pump pressure but can't find any info.
Several people make them, here is one http://www.speedwaymotors.com/Mustang-II-Power-Steering-Flow-Valve-for-GM-Pump-2-GPM,5852.html