So your backhoe won’t stay in place. I assume that’s leaking down while not running as opposed to being uncontrollable while you’re operating it?
Your legs don’t work well. Hopefully that’s the backhoe stabilizers, not the legs you walk on. What are they doing that doesn’t work well? Are they leaking down? If yes, during operation or just when not running?
The joystick shoots out hydraulic fluid like water out of a squirt gun (but that’s unrelated). This joystick; I assume that’s the loader valve, not one of the controls on the backhoe. What has led you to the conclusion this issue is unrelated to the issues with the backhoe?
I’m certainly open to correction from others more knowledgeable but I believe your 5400 has open center hydraulics like pretty much every tractor in that size range. The hydraulics are daisy chained such that the pressure line runs to loader valve first with a power beyond outlet that sends pressure to backhoe, rear SCVs, etc. with 3 point usually being last in the circuit (and of course the backhoe taking the 3 point’s place in the circuit when it’s on the machine). Regardless the exact order of the that circuit, if you have one part of it shooting hydraulic oil at you, it’s not at all unlikely to negatively impact the performance of other hydraulic functions on the tractor even if they “appear” to be unrelated to each other. That daisy chain open center arrangement means all of the hydraulic stuff on your tractor is related to each other to some degree.
So, two points:
1. A little unclear on the details of the problems. Some more detail might help get better answers there if you need more help.
2. The joystick that’s shooting hydraulic fluid willy nilly… fix it. Fix the known problems with the circuit first. You may have additional problems but then again you may not. If you have questions on how to fix it, some detail of where it is on the tractor and where exactly the discharge is coming from (photos are really helpful there) will get you more answers and better answers.