L245DT Hydraulics Theory

[Danmower]

This is info others might find helpful which I gleaned from a Kubota mechanic. I was having problems with my hydraulics not working (FEL & 3pt). Here goes: The L245DT has a single hydraulic pump located on the rt side of the engine which feeds a metal line going back to the '3 point box' under the seat (not sure of proper name). From there, the fluid goes to a small block shaped manifold on the left side of the 3pt box under the seat. This little block manifold has two lines going up to the FEL controls. One of these lines feeds pressure to the FEL control valves (hand levers), the other line returns pressurized fluid when the FEL is not in use. They call this pressurized return line 'PB' or Power Beyond as it allows pressurized fluid coming FROM the FEL control to feed back into the 3pt box and provides 'Power Beyond' the FEL. This PB fluid allows the lift on your 3 pt hitch to raise. When you are using the FEL, the 3pt wont lift. There is a 3rd line coming back from the FEL control, and this is just un-pressurized fluid which comes from the 'drain' side of the FEL cylinders when in use. This fluid is routed through the FEL control and just runs back through this 3rd line into the gear box behind the transmission. The FEL control has its own pressure relief valve (which was the problem in my case). The 3pt has its own pressure relief valve near the little block manifold. To diagnose my problem, I bypassed the FEL by connecting the pressurized output hose from the little block manifold back around to the other fitting on the manifold (which normally receives the PB line from the FEL). Thus the FEL was bypassed and a single hose looped between the two manifold ports. With the FEL control thus bypassed, my 3pt lift started working as normal, indicating my pump was fine (which I had completely disassembled) and my 3pt system was fine (which I had partially disassembled). It DID indicate my FEL control had a problem. I took apart what I think was the FEL pressure relief valve (don't have manual for it and the part didn't look like your typical relief valve), which appeared to have an external adjustment of some sort. I reset it and everything starting working normally. What a relief. BTW, I do have the L245DT shop manual and it is pretty worthless, as far as theory of operation goes. It does have some pictures which can be helpful. No info on the FEL. Hope some of this helps others. In addition to my time, this problem cost me $750 in renting a 'big' backhoe to do some trenching I had planned to do with my Kubota. Ouch!

 

[ronjhall]

<font color=blue>No info on the FEL.</font color=blue>
Danmower
<font color=orange>Kubota</font color=orange> usually has a separate manual for the FEL.
If you adjusted the pressure relief valve to get you’re FEL working. Did you set it at the proper pressure? Having pressure set to high could damage your FEL.

There are a couple of long threads dealing with Hydraulics on TBN. They both started with Bird installing Top and Tilt on his tractor. Your explanation of how hydraulics works on a tractor is very close to how I leaned to hook up my Top and Tilt.

<A target="_blank" HREF=http://www.tractorbynet.com/cgi-bin/compact/showflat.pl?Cat=&Board=owning&Number=24170&page=&view=&sb=&o=&fpart=all&vc=1>Tip And Tilt Click Here</A>

<A target="_blank" HREF=http://www.tractorbynet.com/cgi-bin/compact/showflat.pl?Cat=&Board=owning&Number=32151&fpart=1>Top and Tilt Click Here</A>

Thanks for the explanation in a shorter format than the 2 links above. /w3tcompact/icons/smile.gif