Yanmar 155d Hydraulic lockout issue

MountainDeere · Sep 22, 2017

I've got an issue with the hydraulics on my tractor. When I start it up after letting it sit for a few hours, the 3 pt hitch will only go down but won't come back up and the loader won't work. It will suddenly start working at random now and sometimes when I press the clutch in, it'll work after I release it.

It seems like theres a switch or something that isn't working right that is locking it out. Any advice?

winston1 · Sep 23, 2017

The clutch should have no effect on your lift. How is your fluid condition and level? Changed it and cleaned suction screen lately? No switched on your hydraulics.

clemsonfor · Sep 23, 2017

It almost sounds as if the fluid is over heating and thinning out so much that it's unuseable. I would do what Winston said first. Buy you a $30 pail of fluid, clean screen change filter iF you have one and put it all back togeather. If sill a problem the lift valve or the oring on the lift piston may be suspect, letting fluid pass constantly leading to overheating.

MountainDeere · Sep 23, 2017

clemsonfor said:
It almost sounds as if the fluid is over heating and thinning out so much that it's unuseable. I would do what Winston said first. Buy you a $30 pail of fluid, clean screen change filter iF you have one and put it all back togeather. If sill a problem the lift valve or the oring on the lift piston may be suspect, letting fluid pass constantly leading to overheating.

I'll give that a try but it won't work cold and then suddenly starts working normal.

clemsonfor · Sep 23, 2017

Oh well cancel the idea that the fluid is overheating. It would take awile on a hot day to get that issue.

You still need to do the fluid and filters so we know you have clean correct fluid and the strainer and filter if there is one are clean and clear.

MountainDeere · Sep 23, 2017

It seems like a sticking valve because it's absolutely nothing and then randomly starts working.

normde2001 · Sep 24, 2017

Change the fluid and clean the screen, then work from there.

MountainDeere · Sep 26, 2017

I got it figured out. Turned out to be water in the hydraulic fluid. It's gonna need a few more flushes but it's good as new.

clemsonfor · Sep 27, 2017

That's what most of this stuff is.

So had you not checked it? It would have looked milky if it was fresh run.

Buy you a few pails of the cheap 303 fluid and change it after a few hours of running. Do a few changes.

Next time you drain it I personally would put the plug back in and fill with diesel to wash it...don't run it but just fill and then drain. Help wash the sump out but the lines and 3 pt still would have contamination. That would depend though on how much water is in there I guess.

MountainDeere · Sep 27, 2017

clemsonfor said:
That's what most of this stuff is.

So had you not checked it? It would have looked milky if it was fresh run.

Buy you a few pails of the cheap 303 fluid and change it after a few hours of running. Do a few changes.

Next time you drain it I personally would put the plug back in and fill with diesel to wash it...don't run it but just fill and then drain. Help wash the sump out but the lines and 3 pt still would have contamination. That would depend though on how much water is in there I guess.

It was abit milky and flushing it was already in the plans but it just seemed suspicious that it started working a few times right after I released the clutch.