Well THAT was a pain.
It took me about an hour and a half to manufacture the parts. It took over two and a half hours to install them.
I was determined to do the work without removing the lift and travel levers shafts. It was more frustrating than I had realized. If you buy the kit, the lever shafts must be removed, because if you put a downward facing bolt in the hole on the lever "ear", it is impossible to reach it and thread a nut upward onto that bolt. And since the kit comes with tie-rod ends that have a downward facing bolt, you have to remove the travel/lift lever shafts to install the kit.
(MAYBE you could get in there if you removed the lift cylinder and lift rocker shaft? I didn't try, but I doubt it.)
But using the heim joint and a bolt, you can JUST wiggle a one inch long bolt upward through the lever "ear" and then install the heim joint and lock washer and nut onto that bolt.
But as it turns out, that's only on the lift lever side. That side was fairly fast and easy. Visible and accessible, done in about 30 minutes. Smooth as silk. I put a washer on the upward facing 1/4" bolt and put just a little puddle of weld down in the crack. That holds the washer permanently in place, and fills the gap: we're putting a 1/4" bolt into a 9/32" hole, so the bolt can wiggle around in the hole, and we don't want that. A little lump of weld bead makes the bolt fit snug in the hole.
So I've got this licked.
HOWEVER. The travel lever side took me over an hour to get installed. Nothing can be reached, nothing can be seen. Super, super frustrating. I finally got the bolt into the "ear" and dropped the heim fitting on it and it took me dropping SEVEN nuts before I finally got one to thread on. Once the nut is resting in place, you can only reach it with a single index finger, and you just have to kind of swirl in a circle getting the nut to spin and catch a thread.
UGH.
But I GOT IT!
Kinda. :-(
It turns out that SMewing was right: Using the heim joint on the travel lever side makes the whole shaft assembly sit too low. So the jam nut hits the top of the "footbrake neutral return" lever, so the travel lever is BARELY able to move.
"Ah! we'll install a spacer between the "ear" and the heim joint!" Good plan. That will work. BUT
With a spacer between the heim joint and the "ear" you have to have a 1 3/8" long bolt to attach it. BUT YOU CAN"T GET A 1 3/8" BOLT IN THERE without removing the travel lever shaft.
So it's a Catch-22, at least for those like me who STUBBORNLY refuse to remove the travel lever shaft.
Therefore: My plan will work. If you build up the parts as described below, and put a spacer on the travel lever side, you can do this whole upgrade for about $25 plus some scrap materials laying around. But you will have to remove at least the travel lever shaft in order to install it. And it will be dirty and frustrating. Only someone who is cantankerous and stubborn and cheap should consider going this route.
But if you ARE cantankerous and stubborn and cheap, and you have a drill and a welder, then you might consider it.
So did I remove the travel lever shaft? NO SIR.
As it turns out, my tractor is special.
It turns out that, in the process of reinforcing the frame rails of my tractor in order to prepare it for loader duty, I chose to close up the hole in the frame rail where a pin coming out of the brake pedal sticks through a hole the frame and when the brake pedal is pushed, that pin pulls on the spring that pulls on the "neutral return lever". That's how the foot brake causes the travel lever to return to neutral.
Closing up that hole increased the strength of the frame in that (fairly critical) location. But it meant a redesign of the parking brake system, and I'd like to think the new design is actually a substantial upgrade. I no longer have to push the pedal with my foot and then push some other button or lever with my hand. I just have an "extra" inner foot pedal. Push on the inner pedal and it sets the parking brake. Simple. No thought, no fuss. Push, "click", all set.
I explain the need to close up that hole here:
https://youtu.be/ay-uRitVV38?t=249
and you can see the end result here:
https://youtu.be/ay-uRitVV38?t=3671
The tradeoff is that my foot brake pedal no longer has any effect on the travel lever. Pushing the foot brake applies the brake, nothing more. It has no effect on the travel lever, you have to do that yourself. I'm perfectly happy with that, but some folks wouldn't care for it.
But SINCE MY TRACTOR DOESN'T EVEN USE the "neutral return lever", I simply removed it. And once that was out of the way, I re-installed the 1" bolt and heim joint on the travel side, the same as the lift side. Problem solved. It won't work for anyone else, but it worked for me.
Bob