Steering Problem Kubota M5400 SU

[Stampy]

Howdy to all, I have a 4 wheel drive Kubota M5400 SU with 800 original hours. I purchased it from the original owner last fall. Here's my problem, with the tractor running, but stationary, when I turn the steering wheel it goes about half way and the wheels stop. It feels like the steering locks up (if I elevate the front wheels with the bucket it does NOT improve) lowering the front wheels and putting her in gear (either forward or reverse) the steering frees up and she acts pretty normal. I have replaced the gear oil in the front axel as well as the hydraulic oil and filters and greased everything real good. Nothing seemed to help, she still bindes up mid-stroke. Any help or suggestions would be greatly appreciated. p.s. I did notice a large amount of thin wafer-like fiber board in the hydraulic oil (pieces about the size of a quarter to 1/2 dollar) Now this stuff could have fallen into the oil from above, but I just thought I would include the information just in case it was a clue. Thanks in advance, Jim

 

[rbargeron]

Did something whack your steering cylinder? If you push on the rim of the steering wheel does it get past the tight spot?

 

[Stampy]

The original owner may have, but I've treated her kindly since owning her this fall. That steering wheel pressure doesn't seem to make any difference, however when I tried lifting the front wheels again it went through its full stroke, when I put the bucket off the ground the extra weight made it stick again. It also seems like it doesn't do it in the first 30 seconds to a minute when the hydraulic oil is cold or not aerated???

 

[Tx Jim]

How long since hyd filters were changed??

 

[Stampy]

Tx, It was the first thing I did, with no positive results. If you read my first post you'll get an idea of what I'm experiencing. Thanks, Jim

 

[rScotty]

The original owner may have, but I've treated her kindly since owning her this fall. That steering wheel pressure doesn't seem to make any difference, however when I tried lifting the front wheels again it went through its full stroke, when I put the bucket off the ground the extra weight made it stick again. It also seems like it doesn't do it in the first 30 seconds to a minute when the hydraulic oil is cold or not aerated???

So there are a couple of clues here. Let's see if I've got them right - one being that lifting the front end off the ground helps sometimes but not always.....The other clue being that the steering works normally when it has been setting long enough for the oil to cool off. And then there is that large amount of fibrous material like cardboard that you saw in the hydraulic oil when you changed the filters.

You know, all of these could sure point to some of that cardboard you mentioned being stuck in those little control passages in the steering control valve. Starting from cold it might even be that a bit of cardboard blocking the passage has moved out of the way as pressure let off and things cooled. Might not be oil being cold at all. BTW, the cardboard or fibrous material you describe sounds a lot like what the hydraulic filter is made from. What are the chances that a filter ruptured at some point? You wouldn't even know it until some of the control valves started acting wonky...

Here is what I'd do: First of all, is it possible to back flush the hydraulic system? Better ask your dealer. In fact, ask several. If so, do that and then follow up with new hyd fluid and new filters again. Hate to say it, but if this is the case, you might end up changing those hyd. filters several more times until you get the crud out. The good news is that if this is the problem...and if you can get all that crud out....then it isn't likely to have hurt anything.

A hint on the hyd filters. Mine has two hyd filters, and they are typical kind of filter that screws onto a pipe thread nipple and the lips seal against a machined surface. Those pipe thread nipples are just loosely threaded into the engine block and can come loose. I had one back out with the filter attached!
good luck with it,
rScotty

 

[Stampy]

Scotty, Thanks for your in-depth response. I think you may be right, I wish I knew what the inside of a hydraulic filter looks like because the stuff I found in the oil pan had slight angular bends in the fiber material and a pattern stamped in it (like I said originally, it may have fallen in the oil from above and not been in the system at all, I just don't know) . It was also NOT porous or soft, it was wafer thin and hard. Anyway, I sent the tractor to the Kubota shop today with some of the fiber stuff for their diagnosis (the mechanic, who picked up the tractor said it acted like it was the control box $$$$$$$$ or the pressure was blowing by the valve in the front end. He'd said he would do the pressure tests needed and narrow it down I'll let you know what the damage is. Thanks for your help. Jim

 

[rbargeron]

..... the stuff I found in the oil pan had slight angular bends in the fiber material and a pattern stamped in it (like I said originally, it may have fallen in the oil from above and not been in the system at all, I just don't know) . It was also NOT porous or soft, it was wafer thin and hard.

From the description that stuff sounds like wet brake friction facing material. On your tractor there are 3 disks on each rear axle with facings on both sides of each disk - lots of material. The brakes may still work with some of it missing. Do the brakes make any weird noises?

 

[Stampy]

"r" The brakes don't make any noise and seem to be fine, could that material cause my steering/fetching problem? Jim p.s. Thanks for the great illustration!