The float position on the valve is really pretty simple. Don't let it overwhelm you. There are usually 3 or 4 springs (about the size in a ink pen) that hold the steel balls in place and are pushed by the valve spool when you move the lever.
There is probably some moisture in the end cup and some dirt or corrosion is causing the trouble. Just needs to be cleaned up and put a touch of white lithium grease on them.
hydraulic spool repair kit - Google Search
If this link works, look at item #8 (springs) and #11 (balls) as an example of what they are and where they are located.