HELP-Cub 2072 Hydro Problem

[mwesterlund]

Help anyone Please. My problem continues with a Hydro problem 1989 Cub 2072. When the Hydro fluid (and tractor) warms up the Hydro gets weak and can not pull hills. Even small hills. Hydro lever becomes hard to push. At the same time the power steering gets very hard/stiff. It feels like a pressure drop or restriction and system fails. It never fails completely and rill pull on flat grade. On steep it will stop moving completely and whine. Just no power. No motor strain. Same in reverse or forward. Trunion spring replaced and linkage looks OK and hit with PB..Fluid, filter changed. Cub factory hydro filter being used and changed again just in case restriction. Pulled and cleaned check valves (not sure how to check if they are failing) Upon first cold run (and it does not last long) it seems to work OK. Any ideas? Thanks in advance for any help anyone has.

 

[cfrock]

My guess is that the hydro charge pump is going bad. it is rare that they do but it can happen.
Better try and find another used one and swap it on and see what happens. I have a Kubota tractor that is starting to do the same thing and will have to address it soon.

 

[dtanner]

Michael Westerlund

Could be an issue with the pressure relief valve that controls the pressure the hydro puts out. If it is like the earlier cubs you will find it up buy the two hydro valves. I will see if I can find it in parts look up in the am. But if I were you I would look there. A ball of junk (water glob) in your hytran could be getting sucked in the intake tube on the hydro pump as well. Also a dirty hydro filter could be starving the pump and causing all those issues you are having.When did you last take off the back cover off the rear end and clean all the clumps out and replace the filter and add new hytran ????

 

[mhomrighausen]

Good suggestions so far. Use this... Sauer Danfoss 15 Series Service Manual. Read and study it thoroughly. Use the gauges in accordance with what the manual says. My guess also is the charge pump is going bad. Please keep us posted.

 

[mwesterlund]

Thanks for all the feedback for the "new guy". Good news is all the feedback supports what i have done to date. Next step is to get new relief spring, shim if required and try to build some pressure (which is obviously lacking). Anyone have a good method to clean/clear the valve seat for the valve cone going in from the side? I plan on making sure the cone is seating when i put new spring in. While all looks clean and OK with valve I can not be sure it is tight into housing and able to build pressure. If this works I will post results for others to benefit from. Thanks, Mike...I guess pump may be next..ouch