IH Cub Lo-boy 154 hydraulic problem

nepa · Sep 16, 2024

My mid-mount mower is stuck all the way up. When I push the lever to raise the mower I can hear the motor and pump strain because the mower is already up to the max. When I pull on the lever to lower the mower nothing happens. Even in the float position nothing happens. The mower is stuck all the way up. I changed the hydraulic filter and that did not help. I guess the only places the problem can be is the hydraulic piston or the lift valve assembly. Any suggestions for diagnosing this? Thanks.

oldnslo · Sep 16, 2024

It has been way to many years since I have been around one of those tractors but believe they are a single acting cylinder so power up and gravity down but since you say has float I could easily be wrong.

Can you see the lift cylinder? If yes does it have two hydraulic lines to it or one? If one suspect single acting so would look for lift linkage binding.

Can you see the valve spool? Is it moving both directions from center approximately the same distance?

nepa · Sep 17, 2024

Hi oldnslo,
Yes, single acting hyd cylinder with one pressure hose attached. I disconnected the piston rod and was able to rotate the shaft. The bearings for the shaft are lubed.
Sorry, I do not know about spool valves. The tractor has an assembly where the lift lever is attached to a rod that comes out of the end.
Pretty much, I have surmised that the problem is a jammed hydraulic cylinder or a problem within the hydraulic valve assembly.
I was thinking about loosening the hydraulic line at the cylinder and letting fluid leak out to see if the mower drops. Kind of scares me a little but might be a good test. What do you think?

oldnslo · Sep 17, 2024

When you say disconnected the piston rod does that mean you disconnected the cylinder from the lift linkage and the mower deck still did not lower?

If yes that would indicate the lift linkage is mechanically bound up since the deck should have dropped like a rock without the cylinder being connected.

nepa · Sep 17, 2024

The mower was not on the tractor at the time. I disconnected the rod of the cylinder at the lifting bellcrank to see if the shaft was bound up and it was not. With the hydraulic piston disconnected I could turn the lift by hand. Thank you for following up.