L series jerky 3 point

[k0ua]

Sean, are you suggesting we replace our suction hose's? I have a new one, but my rig is just over a year old, and while it did set outside a few months before I bought it, it has been stored inside for over a year. (except for 100 hours)

James K0UA

 

[Chilly807]

What I'm thinking is that even if the hose isn't cracked, which has happened to a lot of L series tractors, the pump may be sucking some air between the rubber hose and the steel lines.

The filter in the suction side adds a lot of restriction, and air will go where fluid won't.

Why Kubota uses a rubber hose there, other than to damp engine vibration from cracking the steel lines, is beyond me.

The clamps aren't much either, simple spring type clamps with no way to tighten them. I'm going to pull the hose off mine when I get a bit of free time, make sure it isn't cracked. If I can find some better clamps, I'll try them at the same time and see if it improves the hitch action.

Neil Messick's comment about the suction line got me thinking about the poppet valves in the 3 point control valve that rely on a solid flow of oil to open and close them quickly. If the oil is slightly aerated, then it acts as a spring and has some "give" before the poppet will open. This MIGHT result in overtravel of the hitch before the feedback circuit can react.

It may be a wild goose chase, but if it is, it's a cheap one as goose chases go. A little time invested and a cup or two of UDT assuming I lose a bit.

It's possible that the valves have varying degrees of tolerance to air in the oil, depending on how close they are to being perfectly adjusted.

Sean

 

[General Lee]

After looking at the suction line on mine, it's a classic case of a problem waiting to happen.

The suction from the pump (rubber hose with spring clamps on both ends) goes to a steel line, THEN through the hydraulic filter and finally a second steel line going to the sump.

I've noticed some aeration in the oil while running, it may be a problem after all.

Sean

When I get some time this week, I'll look at my suction line and check things out. Its a new machine, been garaged since I've had it but did sit on the dealer's lot a while.

 

[Chilly807]

When I get some time this week, I'll look at my suction line and check things out. Its a new machine, been garaged since I've had it but did sit on the dealer's lot a while.

Even if the hose isn't actually cracked, the pump may be sucking air between the hose and the steel pipes.

Mine has 9.something gpm of fluid flow, when you think about it that's a fair bit of fluid to pull through an automotive type filter every minute, if it can get air it will.

Sean

 

[Chilly807]

I spent a couple hours mowing tonight, then had a look at the sight glass before shutting it down. I had a fair bit of air in the oil, the real question is: How much is normal?

Video didn't turn out that well, what's easily seen with the naked eye gets lost in the video.

Sean

 

[dancour]

Yes, my new L3200's 3PH is jerky too.

Being more specific, the 3PH will raise and lower completely very smoothly but if I try to inch it higher as when using my box blade, it jerks or bounces.

I was told that the L series is the economy level which has been scaled down to compete with the other brands like the NH Boomer to be at a price point that's competitive.

Apparently the L series does not have an "inching" valve that you would sure need if using a sickle bar mower. The better and more costly valve is included in the higher cost Grand L series I was told.

I'm still pleased with all the other Kubota L tractor functions and I'm backed by a super dealer.

The price was great for the L3200 and it seems to me a quality machine but my box blade work won't be as smooth as I'd like.

I imagine most guys don't hook up a box blade or mower and just enjoy the smooth operating loader, 4WD, HST, and power steering. So you won't hear from them until sometime later.

If anyone hears of a reasonable solution to the L3200's jerky 3 point hitch issue, please post.

PS I did have one set of remotes added to my L3200