Troubleshooting hydraulic problem on YM155D

[astromarmot-HT]

My 155D rear/main hydraulic system developed a whining with loss of power when the 3-point is activated. Problem gets much worse when the tractor is up to operating temperature. Checked the fluid and it looks like heavy cream. I drained and replaced the fluid and everything worked like a dream for about 20 minutes. I'm pretty new to hydraulics so I don't know if this is more likely an air or water contamination issue. Any suggestions on what to check next would be greatly appreciated.

I refilled the reservoir with Super Tech 303 Hydraulic/Transmission fluid.

 

[alan-HT]

Water in the old fluid. After draining, did you remove, clean, put back the internal hyd screen filter?

 

[astromarmot-HT]

I did not, that will be my next step. Is there a way to flush the old stuff out, or is there not enough left in the plumbing to worry about?

 

[alan-HT]

If you don't have a Service Manual you can do a search here for how to locate and service the filter.

Flush no. To access the filter you'll drain it again, so use a clean clear container and inspect it. If water forms at the bottom, don't put it back because water is damaging. If it's barely milky-looking, I'd re-use it but schedule another change at 200 hours rather than the recommended 300.

 

[winston-HT]

MIght have something to help you.

 

[astromarmot-HT]

Thank y'all for all the help. I pulled it apart yesterday and the mesh filter was completely gunked up. I haven't put it back together yet, but as bad as that thing was, I'm confident that it was at least a big part of the problem. Thanks again!

 

[Aaron-HT]

Aeration can also make creamy looking oil. If it continues, check out the rubber coupler down on the suction line. It is a short section of hose that couples the two sections of steel line together. If it is cracked or loose it can suck air and not necessarily leak oil. Of course, the more clogged up that screen is the harder it will have to suck and the more air it can pull in.

 

[alan-HT]

You can get special cleaners but I just rinse it in diesel. Check the rubber O-ring gasket is OK and you put it back exactly.