Is this normal?

[RSR]

I just got my new LS XR4145HC last week. Full disclosure: this is my first tractor, and have only run a couple other tractors in my life ... so, despite what I may "know" from reading on here, I have very little to no practical experience.

When operating the 3pt hitch, it seems very jumpy/jerky. This is based on a John Deere I have rented, and a friends B-series Kubota. I've attached a video below. It doesn't seem bad on the video, but it's much more noticeable in person. If I move the lever quickly to a set location, it moves smoothly. However, if I try to feather it and slowly move the lever, it jerks like crazy. The video is with the tractor at idle. If you bring up the RPM's, it shakes the whole tractor. Interestingly, it seems easier to feather/control when running it with the lever at the rear of the tractor, as opposed to the lever in the cab (???).

Here's the full history of the machine. The dealer installed a 3rd function and grapple, plus a rear snowblower with hydraulic chute rotation. The tractor came from the factory with fluids. After running the rear hydraulics on the snowblower, the dealer said he topped off the Hydraulic fluid with Wolfshead. He did not, however, run the 3rd function hydraulics/grapple. After receiving the tractor, I ran the 3rd function hydraulics. At the time of delivery, they were jerky, but with the excitement of a new tractor, getting everything unloaded, etc. I forgot to ask the dealer about it.


The next day, as I was going over the tractor checking everything, I checked the hydraulic fluid and it was at, or slightly below, the low mark. Not having access to the original fluid, or Wolfshead, I topped it off with John Deere Hy-Gard. It took about 3 quarts to bring it up right to the top of the full mark.

After topping the hydraulic fluid off, I ran the 3PT up and down multiple time, thinking maybe there was some air in the lines that was causing the jerkiness. But, the problem persisted. When I checked the hydraulic fluid after running it, it looked like there were little bubbles in the hydraulic fluid. I tried to take a picture against a black background so it was evident (see attached).



So, is it normal for the 3PT to be this jerky, and I'm just getting concerned over nothing, or is there something else going on here?

Thanks!

 

[dodge man]

If it has position control, it might be normal. My JD has it so it stops at an exact point depending on where the lever is set at and it has numbers to show the various positions. So say I have it all the way down and then move it all the way up, that will be a smooth operation. Say I have it all the way up, and I am trying to lower an implement to a certain place, I move the lever a little bit, watch the implement move down, move the lever a little bit more, and so on. Depending on my timing of moving the lever that will make it start and stop and be jerky.

 

[ruffdog]

Your video is "private" so it won't play.

Air in the system will raise havoc with how it operates. Run it for a while and move everything to the extremes so you work the air out of it. If the oil gets bubbly, let it sit so the air can bleed out.

 

[RSR]

Your video is "private" so it won't play.

Air in the system will raise havoc with how it operates. Run it for a while and move everything to the extremes so you work the air out of it. If the oil gets bubbly, let it sit so the air can bleed out.

It should be public now. Thanks for noticing that.

 

[LS Tractor Owner]

Mine reacts just like Dodgeman's does. If I move the lever slowly, the 3 point is "jerky". I have spoken with the dealer about it and he reported it was "normal". My tractor has position control on the 3 point, (1/4 inching), meaning it will move a 1/4" increments. When the lever is moved "faster", it is much smoother.

 

[oosik]

When I did a total hydraulic oil change at 50 hours - the 3-point was "jerky" for a while. With use it smoothed out.

 

[RSR]

Mine reacts just like Dodgeman's does. If I move the lever slowly, the 3 point is "jerky". I have spoken with the dealer about it and he reported it was "normal". My tractor has position control on the 3 point, (1/4 inching), meaning it will move a 1/4" increments. When the lever is moved "faster", it is much smoother.

My understanding is that 1/4 inching, and position control, are two different types of valves. That is, 1/4 inching moves in 1/4 increments with each toggle of the lever, while position control should be able to smoothly, and repeatedly, move to the same location. ???

 

[chas0218]

All the tractors I have ran seem to do that especially at higher rpm running the pump at higher rates. I wouldn't worry about it long as when you put it all the way down it doesn't slam the 3 pt. implement on the ground and it is smooth if you grab it and go from all the way down all the way up.

 

[ericm979]

There's a valve that controls how fast the implement lowers. It's often a knob below the seat. If your implement is slamming to the ground you can turn the knob in to slow it down. When you take the heavy implement off you need to back the knob out or the 3pt arms will lower very slowly.

Watching the video, that's not normal. My Branson's 3pt goes up and down smoothly and fast, even after adding hydraulics or changing the fluid. Like others suggested, run it up and down a bunch of times to get any air out of the cylinders.

 

[RSR]

When I did a total hydraulic oil change at 50 hours - the 3-point was "jerky" for a while. With use it smoothed out.

How many hours did you have to run it before it smoothed out?

I've run every cylinder up and down multiple (10-20+) times.

I've also tried playing with the flow control knob under the seat.

Interestingly, after running the cylinders, there are always air bubbles in the hydraulic fluid, when checked at the rear axle. After sitting for a couple of hours, they rise out of the fluid, and it is clear.

I'm trying to determine if I just got a bunch of air in the lines, that is going to take a lot of time to work out of the system, or if there is something else going on?

Potentially stupid question: Is it possible to suck air into a hydraulic line through a bad seal? (I have no visible external leaks)