Tractor Stuff

The hour meter on my Kubota B2601 sits a few ticks north of 300. In other words, I’ve had a lot of fun with it during the past seventeen months. Most of the hard work is done, but I won’t be fully in “maintain the homestead only” mode until around the first of the year.

I’ve wanted a hydraulic top link for as long as I’ve been aware that such things exist. Being able to adjust blade angle on the fly makes any grading job much easier. In fact, effective use of a box blade is well nigh impossible without one. I finally got around to installing mine this past week. To be more accurate, I finally completed the installation this past week. Beware, tractor geekery follows.

True third-function setups are pricey, and depending on the tractor can be a bit of a challenge to install. I opted for a diverter valve setup that I connected to the front end loader lift circuit. I can’t imagine the need to lift the front bucket and adjust the rear hitch angle simultaneously.

I chose a plug-and-play setup from a small business in Missouri called Tractor Innovations, and probably paid a third more than the acquisition cost for the individual components for the convenience. He advertises a fifteen minute install. He’s right, but only if you’ve practiced. My initial kit installation time was probably right at thirty minutes. The entire project took much longer, as I will explain.

The TI kit itself truly is plug-and-play. Decide where you want the valve within reach of the existing quick-connects, drill two mounting holes, and bolt it in place. Make sure you know which hoses are for which circuit and patch the valve in using the hoses already connected to the valve. Route the longer hoses to the rear of the tractor, choose the mounting location and drill one more hole to hold the bracket for the quick-connect fittings. Assemble the bracket and bolt it in place. Tie-wrap the hoses so they won’t catch or rub on anything, and you’re done. In theory.

The B2601 is a baby tractor, really. There isn’t much real estate to hang extra stuff near the operator’s station. Or anywhere else, really. I made room for the valve and its associated hose nest on the side of the plastic part enclosing the instruments and wiring, on the right side of the machine. It’s tight, but it works. I had to pull the right side engine cover and remove the bolt holding the assembly in place for access. Also, I had to insert the bolts from the back, as there is insufficient clearance behind the panel for the extra length when trying to go from the front.

There are lots of potential interference points where the rear hoses logically should be routed. Eventually, I’ll snake skin the hoses, but for now I routed them as carefully as possible and used lots of tie wraps to keep them where I put them. Then there was the bracket for the quick-connect pair. It’s flat, designed to mount to a flat surface with the fittings off the edge of whatever flat surface is used. The cross-support (shared mounting point for the tool box and SMV triangle) between the fenders was the logical mounting location for my tractor. However, this part is L-shaped, with the flat on the top.  Not wanting to mount the assembly above the support, I borrowed a scrap piece of uni-strut from work, bolted that to said cross-support, and mounted the bracket to it.

The cylinder itself was where the real fun began. The “standard” category one cylinder sold by every farm and equipment store out there for $125-150 wasn’t what I wanted. Those cylinders are adjustable from twenty to twenty-eight inches and since they don’t come with check valves, either you add them or deal with creep.

My original (manual) top link adjusts from approximately sixteen to twenty-six inches. Rarely did I ever extend it past twenty inches. Therefore, said standard cylinders definitely wouldn’t work for me. AMA USA makes several different lengths and all come with check valves already installed. They will set you back at least two hundred federal reserve notes, slightly more if you buy from a large retailer like TSC and/or if you want a less popular length.

I chose the sixteen to twenty-two and a half inch option. It cost me one penny short of two bills from Agristore USA, delivered. I may regret not having the additional three and a half inches that my manual link has, but I doubt it. And if push comes to shove, I can always remove the hydraulic cylinder and reinstall the manual link for specialty situations. The only thing I ever remember stretching it out for was the finish mower. A while back, I started using a longer adapter to connect the floating top link setup on that. Once I made that change, the manual top link stayed short while attached to the mower and it still lifted evenly.

The first hurdle with the cylinder was Kubota’s use of a narrower eye connection than most other manufacturers. The maximum eye width that will fit is ~1.6″ and the standard eye width that everyone else uses for category one equipment is 1.725″ or thereabouts. A couple minutes with a grinder and then some follow-up with fine sandpaper cured that problem.

Then came the hoses. Part of this was my fault for buying everything before I knew exactly how AMA configures the cylinder. I knew they use 3/8″ BSPP threaded ports, and they include BSPP to NPT adapters with the cylinder.

The quick-connect fittings that come with the kit are 1/2″ FNPT. The most common tractor hydraulic hoses have male fittings on both ends, so that’s what I bought. There was only one each 1/2″ and 3/8″ hose of the proper length available from my chosen local supplier. So with the mis-matched hoses, I also bought the appropriate adapters to go from 1/2″ to 3/8″ for each hose.

What I didn’t know was that the BSPP to NPT adapter that comes with the cylinder is male on both ends.
So, I had to go back and get a double female adapter for each hose. Connecting the cylinder to the quick-connect fittings at the end of the hoses from the TI kit:

Hose #1

  1. 3/8″ BSPP male to 3/8″ MNPT
  2. 3/8″ FNPT to 3/8″ FNPT
  3. 3/8″ MNPT TO 1/2″ FNPT
  4. 1/2″ MNPT to MNPT hose
  5. 1/2″ FNPT to male Pioneer quick-connect

Hose #2

  1. 3/8″ BSPP male to 3/8″ MNPT
  2. 3/8″ FNPT to 3/8″ FNPT
  3. 3/8″ MNPT to MNPT hose
  4. 3/8″ to 1/2″ bushing
  5. 1/2″ FNPT to male Pioneer quick-connect

It was hideous to look at, but a function check of the cylinder proved that it worked and didn’t leak. Thanks mostly to $25 bottle of Loctite 545, likely. I figured that I’d use what I’d already bought, and when it came time to replace a hose, I’d get what I should’ve bought in the first place that didn’t need multiple adapters on both ends.

Initially, I set the hitch to about mid-travel with nothing but the quick hitch attached and cycled the cylinder a few times. The hoses were stiff and wanted to hang up on everything in addition to trying to rotate the bracket around its single mounting bolt. Since the tractor was already running, I decided that I’d complete the function/clearance check of the cylinder itself and then try to figure out the hose and bracket issue afterward. I fully extended the cylinder and cycled the hitch from top to bottom. No problems. Then I retracted the cylinder and set the hitch to lift. Something distracted me momentarily, but I was quickly brought back to reality by a CRUNCH! CRACK!

It turns out that a hydraulic cylinder is much larger in diameter than a manual top link. I mean, I knew this but never gave any thought to the consequences of the fact. This additional girth caused it to impact the cross-support and bow it slightly. Also, if the hitch isn’t perfectly centered and the cylinder is fully closed, the upper corner of the quick hitch will also pick a taillight and destroy it. The hitch was slightly skewed to the left, so that was the taillight that it attacked.

I acquired some scrap metal and fabricated spacers to raise the cross-support about two inches. After installing those, I could fully raise the hitch without interference from the cross-support. The taillights were still at risk, but the cylinder will never need fully closed in order to put any implement at the correct angle for use, so that should minimize the chances that I will destroy yet another one. (I give myself less than six months before I kill the next one, though.)

Once that was done and I could raise and lower the hitch without causing damage, I started looking at other clearances. I noticed that at some point during the secondary cycling of the unit, the hoses had caught or flexed or something causing the mounting bracket to rotate, then bend, then stress the entire thing enough to cause the breakaway feature to activate. I tried moving the bracket to the right side seat belt anchor. Same problem. Then I tried attaching it to one of the bolts that holds the PTO shield in place. That was worse.

I then flipped the bracket over and mounted it to the top of the cross-support using the hole that I originally drilled for the uni-strut. That almost worked. Almost. The hose stiffness rotated the bracket around the bolt holding it to the cross-support, despite it being as tight as I could get it. Neither hose popped loose, though. I would’ve been fine leaving it there, double-nutting it loose enough to allow it to swivel but keeping it secure, but the hoses also got hung up on the fender edges and quick hitch release handles. It would only be a matter of time before something caught with enough tenacity that a hose would be either cut or yanked loose.

I fabricated a 3″ riser/spacer and mounted it between the cross-support and the bracket, in the hopes that the additional height would help with the pinch points and stretch things out enough that the hoses would stop catching on stuff. It did help, and I was actually able to lock the bracket in place and use the setup with my box blade for a couple of hours. When I stopped to inspect things, I saw several places where the hoses were gouged from continued clearance problems that I’d missed. It’s just as well. It looked horrible.

I gave up and bought a set of 1/4″ hoses and the minimum number of adapters to connect everything. Specifically, 3/8″ BSPP male to 1/4″ female reducing adapters on the cylinder side and 1/4″ to 1/2″ bushings going into the new quick-connect tips. My thought process was that the smaller hoses should be less unwieldy, and maybe they wouldn’t cause things to bend or pop loose. And maybe, just maybe that would help with whatever was binding them and causing the gouging. To help with that last part, I put snake skin on the hoses from end to end.

Almost as an afterthought, I also ordered a bolt-on swivel with a threaded stud to further allow movement while keeping everything secured. When the swivel arrived, I tried again. I removed the riser and temporarily bolted the swivel directly to the cross-support in the same location that I’d been using. Then I attached the hose bracket to the swivel stud.

Next, I hooked up the new hoses and started checking function and clearances. I didn’t like how everything swung during movement. I unbolted the swivel and tried to find a better place to put it. I finally settled on the fender, just above the PTO and just forward of the ROPS. Finally, everything seemed to be good enough. The hoses still rubbed up against the occasional sharp edge, but the snake skin allowed them to slide without getting caught. The swivel allowed one of the bracket bolts to scratch the paint off the ROPS. Everything else looked good. I went to work.

An hour of solid blade work later, I stopped to inspect everything. No surprises. Everything was still secure, the snake skin kept the hoses undamaged, and the aforementioned scratch (that I can absolutely live with) were the entirety of the situation.

Installation finally deemed complete.

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