MX5100 Jerky 3pt hitch

paulwestski · May 16, 2013

kiotiken said:
Sounds like you have all the info you need. It has a jerky hitch and you know from your experience and everybody elses here, it's not going to go away after the dealer prep. It also would have been pretty easy for him to confirm the fluid level in a matter of seconds, funny how he didn't offer. If you don't care about the jerky hitch, problem solved, if you do, look at another model or make. It's been made very clear in plenty of threads on TBN, there is not fix, no solution, it's just they way they are.

MORE INFO on the flow regulator that fixed the issue........sorry I thought I was quoting another poster

paulwestski · May 16, 2013

smweatherman said:
Unfortunately, in my experience, yes. I have an MX4700 bought in Dec 2010. The 3pt acted just as you show on your video. Really annoying and even dangerous in some situations. Dealer tried to work with me and had tractor at shop for almost a month and even had BIG KUBOTA in to look at it. They tried adjusting the 3pt control valve, replaced the 3pt control valve and even tried a similar valve from a different tractor. Nothing improved the situation without causing other problems. The thinking was the output of the hydraulic pump, in gallons per minute is so high, and the volume of the single 3pt cylinder is so low, that it abruptly jerks the hitch up in increments instead of the nice, steady, slow rate you might expect when moving the control lever slowly. Instead of a steady, slow movement, it jerks up, then off, then up, then off.....

I finally installed a Pressure Compensating Flow Control Valve after the loader valve, but before the 3pt control valve. (Fluid goes to loader valve first, then 3pt, then rear remotes if installed.) I can reduce the amount of flow going to the 3pt (with excess dumping back to tank). So by adjusting the flow control valve I reduce the amount of fluid going to 3pt, it moves more slowly and much more smoothly. This also reduces flow to the rear remotes. I use that too when I have my snow blade on the FEL. The power angle is connected to rear remotes. By reducing the flow I can get the angle to change at a nice controlled rate instead of slamming back and forth or needing to be very delicate with the control lever. I really like the mod so far. It is a work around, not a fix, but has been more than sufficient for me. I only spent about $150 total, all bolt on, can be removed if needed. Also, this does not affect 3pt lift capacity, just speed, and if I set the flow control at the max setting none of the fluid bypasses and everything works like stock. The pressure drop across the valve I installed is less than 100psi at all flows and pressures so heat build up, pump wear, etc., should never be a problem.

Search for "Jeff's Homebrew Jerky Hitch" on this forum. I pretty much stole his idea that he used on a different tractor. If you are seriously interested I can give more specific info, pictures, etc....

Best of luck. The flow control valve and hydraulic top link are the best additions I have made to the tractor.

Wxman

Please forward me more information on your fix pictures would be nice also
Thanks

Chilly807 · May 16, 2013

3boys865 said:
Dealer prep or other adjustments will not make the hitch smooth. It is not designed to be smooth. The response I got from my regional Kubota rep was that the value tractors (Standard L's and MX's) are not engineered to have a smooth hitch. If you want or need a smooth operating hitch, you will need to purchase a Grand L or M series Kubota.

I can't say anything bad about the MX5100 otherwise. It provides a lot of tractor and power for the money, just depends on what you are looking to use the tractor for. If you plan to do any grading, use a PHD or any other implement that would require fine control over the 3PH, then you will not be happy with the 3PH performance. If not, you will not even notice the jerky hitch. It is smooth when raising quickly, just can't feather it up smoothly.

I returned my MX5100 after 2 weeks and purchased a Grand L 4240 because I needed a smooth hitch for grading. Couldn't be happier, it was the right decision for me. If you will mainly be doing PTO or FEL work then the MX5100 is a great choice.

Hope that helps...

Or alternatively, you can buy any colour other than Kubota orange and get a smooth hitch. I've never seen any similar complaints about a Deere, New Holland, Case etc. product.. they have other issues, I'm sure.

Sean

3boys865 · May 16, 2013

Chilly807 said:
Or alternatively, you can buy any colour other than Kubota orange and get a smooth hitch. I've never seen any similar complaints about a Deere, New Holland, Case etc. product.. they have other issues, I'm sure.

Sean

Sean, yep your right about that, other brands have value tractors also, but they chose to NOT cut corners on a basic function of the tractor like the 3PH. Don't understand why Kubota thought it would be a good idea to cut corners on the 3PH....

Chilly807 · May 16, 2013

paulwestski said:
Please forward me more information on your fix pictures would be nice also
Thanks

I'd like to see them too, this is still in the back of my mind for a day when I have some extra cash and some time to install the valve.

One other thing has been rolling around in my mind too.. we had another member here with a B series with position control (B2400 I think it was), that had a cycling issue with his 3 ph. He changed the O-rings in the valve and cured his problem. I've been pondering the possibility of that causing the trouble with the L and MX series. It's possible if the O-rings were swollen (wrong material maybe?) that they would be too tight on the valve spool and cause it to stick or chatter instead of sliding smoothly.

To be honest, I haven't even looked in my parts book to see if that valve even has O-rings or not (too much else going on) so this is just musing on my part.

Sean

smweatherman · May 16, 2013

paulwestski said:
Please forward me more information on your fix pictures would be nice also
Thanks

Give me a day or two and I will put some info together. It has been a few months now so I probably can't give the details off the top of my head. I don't have any pictures yet either, but that should be a quick fix.
I just used the 3pt yesterday with the rotary mower. Even with the mower I left the rate reduced a good percentage. It is slower, but fast enough, and alleviates a lot of the 'slamming' when the mower reaches the top of its travel. I still like it for a work around type solution.

Chilly807 · May 16, 2013

Is there any way you can get some video of the hitch with the valve fully open, then a second video with it restricted to a smooth rate? I'd love to see the difference, as I'm sure everyone else would too.

Thanks,

Sean

paulwestski · May 16, 2013

smweatherman said:
Give me a day or two and I will put some info together. It has been a few months now so I probably can't give the details off the top of my head. I don't have any pictures yet either, but that should be a quick fix.
I just used the 3pt yesterday with the rotary mower. Even with the mower I left the rate reduced a good percentage. It is slower, but fast enough, and alleviates a lot of the 'slamming' when the mower reaches the top of its travel. I still like it for a work around type solution.

Thanks
Get the info to us when you can

smweatherman · May 16, 2013

Camera took better pictures in the dark than I thought it would so here is a first post.
I installed a Brand Hydraulics pressure compensating flow control valve, FC51-1/2. It will handle 3000 psi and up to 16 gpm flow. They have a decent web site with specs, dimensions, etc... at BRAND Hydraulics suppliers of hydraulic valves and pumps. I purchased from Northern Tool. This valve has 1/2 inch female NPT connections. They make them with SAE ports as well. Other companies make these valves too; this is what I found to be available to me.

I made a mounting plate out of some 1/4" steel plate. The other items I used were: 2 short lengths of 3/8 inch hose with 8FJX ends. (#8FemaleJIC), 1 8MJ-8FJX-8MJ female run tee, and 3 8MJ-8MP90 fittings (#8male JIC to 1/2 male NPT 90 fittings).
That is all it took.

The flow control valve has two holes for mounting. I bolted it to the plate I cut and mounted the plate using two bolts that were already in place for the factory mounting of the loader control valve. I just had to use longer bolts. I actually mounted the flow control valve rotated 90 degrees clockwise for a better fit in my application. I cut a 'notch' in the plate for one of the lines to be able to go straight back. I was a little space constricted because of a toolbox I had mounted in the area before this. I will refer to top, bottom, etc.. as it is mounted (pictured).

The loader control valve has three ports: P, for pressure I presume, T for tank and PB for power beyond. I didn't touch the P port. The flow control valve has IN, CF (controlled flow) and EX (excess flow).

The Tank port exits straight out the bottom of the loader control valve. I disconnected that hose and inserted the tee mentioned above between the hose and the valve port with the additional connection pointing straight down. Then using one of the new hoses I connected this tee to the EX (excess flow) port of the flow control valve using one of the 90 male pipe to JIC adapters. As mounted the EX port comes out the bottom of the flow control valve. This allows any excess flow, the fluid I don't want to use, to return to the tank the same way excess flow from the loader control valve does.

The power beyond flow exits the loader control valve on the top outside edge on my tractor. It exits into a 90 degree fitting that is connected to the hose that routes fluid to the 3pt and rear remotes. This is the flow I want to control (reduce). I disconnected the hose from the 90 fitting on the loader valve leaving the fitting in place. This hose is then connected to the CF (controlled flow) port of the flow control valve using one of the 90 male pipe to JIC adapters. As mounted the CF port is on top of the flow control valve.

The second piece of hose is then used to connect the PB port on the loader valve to the IN port of the flow control valve. The third 90 male pipe to JIC adapter is used on the IN port.

Now: the loader valve and loader work as they always did. Power beyond (the loader valve) fluid goes from the PB port to the IN port of the flow control valve. From the flow control valve the fluid is either sent from the CF port to the 3pt and rear remotes or 'diverted' to the EX port which returns the fluid to the tank through the tee installed on the loader valve T (tank) line. Reducing the amount of fluid at the CF port (what we want to do) just increases the amount going through the EX port back to the tank. The amount of fluid at the CF port is controlled by the lever on the flow control valve, and in my case is adjustable from 0-16 gpm. The valve 'compensates' for differing pressure and keeps the flow at the dialed in setting. My tractor only has a hydraulic output of 9.2gpm, so on the valves 0-10 scale I have to get down below about 6 before anything happens. I seem to run at about 3.5 on the scale for most things right now, slower, but not too slow. It is adjustable from the seat with no tools at any time. Slower doesn't really fix the problem, but it masks it really well. Slower, less momentum, less jerkiness. Slower doesn't bother me nearly as much as the jerkiness. I can return to factory at any time by simply adjusting the valve to a 'controlled flow' equal to or greater than the 9.2gpm my pump puts out.

I hope this description helps make sense of the attached pictures. I will work on some videos of hitch in action next time in use. The hitch is empty right now.
From Seat