Kubota M59 hydraulic return not working

lwm · May 3, 2016

Hi, long time no talk, I've been out using my tractors

This is a repost from parts/repairs, I posted in the wrong place.

I put my grapple (WR Long, *love* that thing) on a couple of days ago, it worked fine for about 5 minutes and then went kaput. In fact the whole tractor hydraulic system went haywire.

It feels like the return part of the circuit is jammed up. Symptoms:

grapple will open fast, won't close. I can lift it up and tip it forward and it flops closed but that's it;

loader lifts slowly/weakly and goes down equally slowly;

3 pt won't come up unless I crank the throttle open;

when the tractor is off with the loader on the ground and you move the loader control arm it settles, so the spool seems to be working.

The tractor has 443 hours, had a full filters and fluids service 60 hours ago, all Kubota fluids and filters. We (my mechanic and I) pulled the return filters and they are clean, oil dumped out of them nicely and the oil was clean (kiss $125 SUDT good bye). The fluid level was fine when things were messed up, we checked before removing the filters.

My mechanic is stumped and doesn't know what to try next. He is grasping at straws and wants get new filters and fluid and "see if that works". That sounds like a $250ish guess.

Anyone have any suggestions on how I figure this out? Much thanks in advance.

J_J · May 3, 2016

Start checking all the QD's.

teg · May 3, 2016

How did you plumb the grapple? or did you use one of your 3 spools to run it?

lwm · May 3, 2016

teg said:
How did you plumb the grapple? or did you use one of your 3 spools to run it?

M59's are skid steer compat, it has a 17GPM 4th remote with thumb buttons on the loader control.
So the grapple is just standard, has the big skid steer connectors (which I hate).

teg · May 3, 2016

So if you disconnect the grapple... does it return to normal or is it still screwed up?

jenkinsph · May 4, 2016

J_J said:
Start checking all the QD's.

x2^^^^^

If everything worked prior to plugging in the grapple I would suspect the quick connectors and their lines back to the valve. Just a wild guess but I am thinking something came loose from one of the quick couplers and is jammed at the valve. If the return from the valve is dumping back to tank that might allow the hitch to operate slowly at high rpms. To be clear if most of the flow was being returned to tank that would not leave much for the other functions to operate on. That is my best guess and is a place to start.

lwm · May 9, 2016

Hey all, problem solved! Problem was created by an idiot (me). The M59 has a fancy auto leveler feature and when you turn that on and use the front remote, the hydraulics go haywire. Turning off the auto leveler does not immediately fix it, but if you open and close every ram on the tractor then the problem corrects itself (went through this twice, worked both times).

Another tip in case someone else wants to take the filters off without losing $200 of SUDT, taught to me by Mission Valley Ford's Kubota mechanic, is this: find your shop vac and find the conical attachment. Pull your filler cap and shove the attachment in there, turn on the shop vac. Unless you have the worlds most powerful shop vac, it won't suck up the fluid but it does create a vacuum and the fluid won't dump all over you when you pull the filters.