Hydro problem solved

[Cvans]

Earlier I asked on a different thread what it takes to get these older hydro's to run at a consistent speed. Today I tied into my 129 and after about to hours of studying and modifying it now works the way I would imagine that it did when new. The best part is, it cost nothing I can now till from one end of the garden to the other without messing with the control.
It seems that getting all of the play out of the trunion springs is necessary and getting the right preload on them is critical. I was able to do this without removing the plate from the pump. Simply shielded the pump shaft from weld splatter and built it up until the hole in the plate was too small for the springs and associated parts. When all the parts are reassembled there should be no play between the two plates the springs. The springs should have to be compressed slightly to fit into the trunion and that assembly should fit into the other plate with no slop.
I really liked this tractor before but I'm liking it a lot more now that I don't have to hang onto that hydro handle.
I hope you can understand my babble.

[Matt G.]

You could have accomplished the same thing with a couple washers between the caps and spring, and consequently not had a permanent modification.

[Cvans]

I considered that but my trunion was worn so bad that it was about to fall apart and I don't like looking for parts in the garden.

[RChristensen]

Normally when you do that you loose the smooth transion when you start and take off spinning your wheels. There was a reason IH designed the two spring control. It may work good for tilling but might be rough for mowing.

[Cvans]

Thankfully, tilling is all it does. Your right though, the little bit that I drove it on hard ground when you pull back on the handle it does slow down right now. I didn't notice too much difference when taking off from a stop. The other thing I noticed is that finding neutral is much easier now and it doesn't want to creep after setting for a few minutes.