Yes, I too am on good terms with my dealer. So, after all this discussion and, going back to the dealer a couple times here are the results agreed to with my dealer early this morning:
Dealer has my tractor as stated looking at the valve situation including my flail mower. Their shop foreman verified there is no valve adjustment rather saying, the valves used in my TnT from Kubota will leak off above 800lbs weight but "having Zero bleed down with a 700lb mower hanging out there just is not going to happen". He also tested the bleed off time saying, the valve was in "speck" with the 700lb mower. He added that, when driving to and from fields or on roads with implement weight bouncing up and down can raise the pressure on the system beyond 800lbs causing bleed down to sometimes happen quicker. For now, I must believe him, not having spec sheets and all for these valves but also feel he is being honest with me AND, am not opposed to trusting folks until they prove otherwise..
Solution:
Dealer offered two fixes, either work for me:
1. remove the tilt cylinder and hoses plus replace the manual system along with some credit or cash return, whichever I want. This results in top cylinder being left in place but having original manual tilt adjustment when needed.
2. Install the lockout valve (Leonz suggestion) leaving the tilt cylinder in place then, when wanting to "tilt" just open and close the valve. He said Kubota factory does not recommend the lockout valve but he says there is nothing to damage by having one? I asked about my tractor warrantee et all, he responded nothing he would do will affect warrantee. I said go ahead and put in the "lockout" as I may want to use "tilt" at some time later.
So, thanks everyone for all the heads up, your knowledge and your suggestions. Have learned quite a bit about rear hydraulics and Flail Mowers both this past two weeks or so. Now, waiting my tractor coming home tomorrow and BTY- my dealer says "no charge" for anything including pickup and delivery of 25 miles each way...
Ricn