I have has similar issue with the lever activation on my nose gear for my A10. A little flex in the system caused the lever travel to vary and the valve to leak. It worked fine out or depressed, but partially it caused a problem.
I reworked mine by making sure the structure around it was solid and also used a softer endpoint.
I used two fuzzy sides of velcro(so they don't stick) so the the lever would be pushed firmly but could also not have too much push on it. This worked for my A10.
I had it hard mounted in my f18 on the nose gear and that worked fine too.
I did have one break (plastic arm) also.
My uB has the over travel trigger, this works well but also doesn't ensure that the gear are retracted before triggers the nose door.
I just have the gear servo slowed down so it works fine in the air.
Good luck
Dave