I hydraulically lift the mid-mount mower on my Kubota B4200D. But it doesn't stay up. It descends to the ground in 2-3 minutes. It's gotten worse over the last 2-3 years (it used to descend much more slowly) . There's no evidence of hydraulic/transmission fluid leakage, as fluid level is full and has not declined over at least 2 years.
Mower drops to ground
- Thread starter Clunksta
- Start date
The hydraulic cylinder(s) likely have worn internal seals. Not sure if rebuildable some are some aren't
Lmichael thank you for your response. My shop/service manual suggests that in addition to hydraulic cylinder leakage (cylinder cap O-ring broken, piston O-ring worn or damaged, cylinder itself worn or damaged) the problem might also be caused by a malfunctioning control valve. Is there any way to determine whether it's a hydraulic cylinder issue or the control valve before I start tearing it apart? Thanks in advance.
Oh, IDK. I am no expert on hydraulics. While I like the "fingertip" control in some ways I would simply prefer manual levers. A while back I had an old (really old) Allis Chalmers garden tractor Near as the dealer could tell it was perhaps a 1961/62 model. It had hydraulic implement lift, and a cursory hitch similar to a 3 point. I bought it in 1990. Rebuilt it, restored it. Installed a brand new 32 cu in single cyl B&S engine on it when it's original 10hp blew head gasket and the rod bearing. Rebuilt the main center gearbox, the mower deck and so on. Just before I sold it, about 6 or 7 years ago IIRC I was having issues with the mower deck again. Easy enough to fix but parts were another matter. I could not even get blades for it. So, I sold it and all the accessories (rototiller, snow blower grader blade and a couple snow blades and all the hitches. In addition if I needed to lift the mower deck or the blade, it would simply fall back down. Meaning I had to hold the lever to maintain pressure.
I then got another large frame Simplicity machine. but when I would have severe allergy issues wife took over lawn duties and such. She hated driving that Titanic around the yard. But it too was beginning to show signs of issue with the hydraulic lift. Again here I figured it was the cylinders as it ran off the hydro unit and the transaxle was fine. So I got a little Honda 4514. Honestly it was a sweet little machine. And it would still be my driver if I hadn't gotten such a great deal on this Kubota and I've always wanted a Kubota diesel machine. And yeah, even this one the mower deck will gradually work it's way down. Not sure what I will do about it though. Definitely no expert on hydraulics
There should be a lowering speed control knob below the seat. Raise the lift, then turn that knob all the way clockwise. If the mower drops, the cylinder is at fault. If it stays up, the control valve is the problem.
^ That test will tell you. But if fluid is not ending up on the ground the cylinder is likely not the cuplrit as a cylinder cannot move without fluid leaving it, assuming we are talking about a single acting ‘push’ cylinder collapsing.
Pretty sure the 3ph lifts the mower. If fluid leaks by the piston ring, if just goes back in the case.
whitetiger
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Kubota tech..BX2370, RCK60, B7100HST, RTV900 w plow, Ford 1100 FWA
The 3-point hitch raises the mid-mount mower deck so if the cylinder is leaking you will not see any oil leaking externally.
PoTreeBoy, Vigo, and whitetiger, I closed the lowering speed control knob and the mower still dropped. Makes my repair plan straightforward - I'll be focused on the hydraulic cylinder and piston. Many thanks!
From what I remember about my BX22, and I believe that yours is very similar, the cylinder is inside of the machine and you have to remove the top cover to access the lift cylinder. Not a job for the faint of heart because of all that is involved in accessing the cylinder. If you don't get it right the first time you have the fun of doing it all over again. I gave it to the local Kubota dealer to fix and it turned out that it was nothing more than low hydraulic pressure. A few shims later and for $475 it was repaired. I would have thought for that amount of money that they would have at least changed the oil and filter. Nope, they socked me for $22 per shim and $30 for incoming transportation. The labor was the balance. Needless to say I have never gone back to that stealership again.