I haven’t seen anything in the operators manual on my 05 Case 430 about a way to make the booms float... does anyone know if that was available then?
There is a float button in a lot of newer machines. In older Case machine with mechanical (H-pattern) controls, try pushing down (towards the floor) with the left control. Right control if you have ISO pattern. Like your doing a boom down, but push a little more, it may lock into float.
There is no ISO contols on the servo machines IE 400 series (series 3 has pilots which ISO is an option). I never use float but if I remember correctly and it was quite a while ago, but if you depress the loader up/down controller (left hand controller) and depress it all the way down, I believe it goes into detent. Try it and see if that works.
It has float on the boom control. Just pull the left hand stick all the way toward you. You may have to get a little rough with it because it's a pretty stiff detent to start with and if it hasn't been used in a while it tends to get even stiffer.