I've got a Kubota R520 that sometimes won't move after the parking brake is applied. Sometimes it starts working after trying switching from forward to reverse or turning the parking brake on and off. This is apparently a fairly common problem from searching but no one has posted the fix. I suspect its a sticking solenoid the way it comes back to working. Some times it can be quick other times it could be 10-15 minutes messing with it. If you don't use the parking brake it works fine all day but you can only start it with the brake on. I haven't been able to find a wiring schematic so I'm having trouble shooting it.
Lol I just fix one start with pulling the fuse cover off check voltage if good does the light comes on dash brake and goes off when turned off than check power to lever yellow black wire no power brake off brake on power to wire if good brake solidnid on hydro system needs checking power two wires one ground other is ground next you go deep floor cover you will see to solenoids on pump each one has two wires ground and power neutral no power if you have a power on one or the other check ground cont
If all good you got to go to the relay this one was mounted by fuse box