B7100, B219 Loader Control Valve Issue

Have the same loader, and had the same problem. The detent mechanism can be disassembled without getting into the hydraulics. Yours is probably rusty like mine was, & my neighbors was the same. (different Kubota tractor, loader, & valve, but similar layout) On the front of the valve, (opposite the levers) there are a pair of caps that cover ends of the spools- the longer one houses the detent parts. The end of the spool has a cross hole which contains a spring & 2 steel balls. The inside of the cap has a ridge & a groove- in normal FEL operation, the spring loaded balls stop against the ridge, and when pushed forward to the float position, they compress into the hole in the spool, then pop out in the groove, locking it in the float position. Mine had rusted to the point where the spring & balls no longer existed. Inside the cap was pretty bad also. Dealer (and Cessna) both told me parts are no longer available. I just cleaned it up, re-assembled it minus the bad parts, & if I need float, I hold it in manually. My neighbor could still get parts for his, so we replaced the parts in his, now it works great. It was a major PITA to hold the balls & spring in place while screwing on the cap, but it can be done. I suppose one of these days I'll make replacement parts for mine, but for now it's just not a high priority for me. If you take it apart, be prepared to have the balls & spring (or whats left of them) go flying, & be prepared to have fun putting it back together. Another neighbor has a Yanmar with the same setup, and we were able to disassemble his, clean the rust, grease it up & re-assemble it, & now works great. Just depends on how bad yours is.
First pic shows the Cessna valve with the two caps highlighted.
2nd pic is the exploded view of my neighbor's valve, (similar) so you get an idea of the ball detent mechanism. Keep us posted….

No problem, maybe you will help me with something else one day.

Any source for the detent spring/ball replacement?

I have a similar problem and the ball/spring turned into brown mud. The rust balls has a dia of ~3.8mm. Nowhere to see the spring.

Assuming nowhere to get the replacement, I bought some 4mm stainless balls and planning to drill the hole to suit if needed. I wonder if someone knows how much compression force the detent spring has roughly, like 1lb? 8 oz?

Another thing i would add, something to help keep water off the controls. Will help somewhat.

Last place of work, star operator plows snow with wheels a foot in the air, cranked to one side. Aparrently using float is the wrong way. Least i didnt grind the cutting edge off in one winter.