L**40 rear hydaulic pressure
- Thread starter kuboman
- Start date
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oldnslo
Super Member
Once again, this does not make sense. Last time I Checked Pascal's Law states "that fluid in confines chamber will have equal pressures in all directions." By closing off the RR you in essence have a contained volume of fluid from the RV to the RR. Pressure in this line should be relatively constant from one end of the line to the other.
Can you hear your Relief valve when it operates? If yes did the sound seem to change when shifting the RR Vs the FEL? Should be none but....
There is no logical explanation that I can think of to explain what you are seeing. Back to our regularly scheduled program of :mur::confused2:
Dang my head hurts..
I will retest and report back. Not sure what I am doing anymore:confused3:Should have done more:drink:and then I would not be so:confused3:
Somebody smack me silly.:ashamed::ashamed:
I retested the curly test. Must have been in the :drink: yesterday but this is what I got today.
Deadheaded the curl to 800psi.
Deadheaded the RR, as soon as I did the RR pressure went to 3200psi and the bucket curl whet to 2500psi.
Hope this makes sense to someone but I have no idea what I did yesterday.:confused2:
I retested the curly test. Must have been in the :drink: yesterday but this is what I got today.
Deadheaded the curl to 800psi.
Deadheaded the RR, as soon as I did the RR pressure went to 3200psi and the bucket curl whet to 2500psi.
Hope this makes sense to someone but I have no idea what I did yesterday.:confused2:
Leejohn
Elite Member
Well try this again. The loader valve is bypassing the relief valve and the 3000+psi that you are getting is the safety opening. I don't think I would put hi rpm on the tractor because I wouldn't think that valve can handle the full flow of the pump. The 3pt refief well not open until there is more load on it that it can't lift. The feed back well not let the refief open if there is no weight on the 3pt. Have kubota put a new loader valve on. I would also ask the dealer if you could open the old valve up and look inside of it.
oldnslo
Super Member
Lee,
According to the hydraulic schematic from the WSM (reference page 5 of this post, attachment #2 from 4shorts) the FEL relief is the system relief and the only relief in this system. There is no relief on the rear remotes or the 3PH and the 3PH is the last valve in the circuit and could not protect the FEL or RR in any event.
Roy
Leejohn
Elite Member
That is true and that is why I'm saying there is something not right with the loader valve.
I did give it some rpm, not max but close and the pressure at the RR stayed steady at 3200psi.
oldnslo
Super Member
Question I have is, what in the loader valve would create higher pressure down stream? I keep coming up with the conclusion of nothing.
I cannot see how it could be plumbed incorrectly since operating the FEL stops flow to rear remotes.
I am open to any and suggestions on what the problem is.
Roy
You and me both.
Well like the Kubota tech said "that's just how it is".
Since they did sort of duplicate my situation with another tractor (cabbed) there is in my opinion a design deficiency.
I am quite sure mine is operating as it was designed to. Just wish someone could explain what is happening. In the mean time I will make sure any implement has good hoses.
