109 Hydrostatic will not move

[olds45512]

Originally Posted by Buickguy

I will do that tomorrow. Thanks for the suggestion. Hope it works.

PS: how many quarts of fluid?

7qts.

[CubDieselFan]

About 7 with the filter. Buy 2 gallons of fluid of your choice. I use hy-tram but I use cheaper stuff when I am trouble shooting.

[Buickguy]

I changed the fluid and installed a new filter. The tractor now moves some, but when trying to move forward, it will only move forward on flat ground. When trying to drive up a small incline it just will not go.

It seems like it is trying to go into both forward and reverse at the same time.

I can drive the tractor up the incline in reverse without any problem.

Any more suggestions? I appreciate everyone's help.

[Buickguy]

I have a 109 hydrostatic that all of a sudden started to not want to move when moving the drive lever and when it did move it was jumpy. It seemed like it was engaging in both forward and reverse at the same time.

On recommendations from you knowledgeable individuals (thanks a bunch) I changed the filter and fluid. There was no change.

On reading the forum posts it appeared that there might be a problem with the hydrostatic valves. I had them rebuilt by the individual in Ohio based on positive comments here on the forum. Still no change.

The condition is that when I push the hydrostatic lever forward or in reverse many times it will not engage. And when it engages it is not smooth.

On the power side, I can cut the grass on the level, but as soon as I try to go up any incline in forward gear it stops and will not go. It seems like the tractor is going into reverse and forward at the same time. I can back up the same incline without a problem.

I am at a loss on what to do next as I am not that familiar with this system. Note that I have had this tractor for almost 40 years and it has performed flawlessly up to now except I have had to rebuild the engine a couple of times.

Your help is greatly appreciated.

[olds45512]

I would remove the tunnel cover and the rear fenders and inspect the trunion on the pump and the linkage's. here's a link talking about the trunion.

http://www.onlycubcadets.net/forum/s...Trunion+repair

[johncub7172]

I agree with above idea of control issues.

[J-Mech]

Well..... It sounds like you have used this tractor a lot. Having the engine rebuilt a couple times. 40 years of owning it is pretty neat.

I do agree that you need to check out the hydro control linkage, and more than likely it is completely shot. If you haven't done anything to it in the 40 years, I know it's shot. But, I struggle to think that is the issue.

It is possible that you have a broken pin on the hydro swashplate trunion shaft inside of the transmission. It makes the hydro act like you are describing, but a lot of times when it breaks, it is hard to find neutral. Do you have issues finding neutral?

Only other thing it can be, and this failure will also give the symptoms you describe, is that the hydro is actually wore out and it is having plate lift-off. That is where the slipper pads, and rotor plates actually get worn off enough that when the hydro gets under load, it actually floats the piston block off the valve plate. Now, if that is what is happening, then 1.) You can't fix it. (Affordably) 2.) You have worn out your hydrostat more than most anyone ever does and 3.) It is caused by use..... but moreover a lack of maintenance. From what you say, changing the oil and filter to help it sounds like it may have been the first time you did. 2 motors is a long time to never service the trans. May in fact be time to find a good use hydro.


I merged this thread into the original one you had. No need for another thread, you still have the same issue.

[Buickguy]

Thanks for everyone for your help. I will work on your suggestions to see if I can get this tractor working again.

[sawdustdad]

Is it possible that the spirol pin through the drive shaft at the hydro input shaft has sheared? It would not be apparent, and the sheared pin might catch occasionally and the drive shaft will turn the hydro input for a while, until under load, it releases and the drive shaft spins without turning the hydro? It might tend to catch in reverse? This would be something that would happen suddenly, and could create the symptoms you describe that appeared out of nowhere.

I suspect (though Jon is much more knowledgeable than I) that the worn out hydro situation would not be something that would appear suddenly. Nor would the loose/faulty hydro linkage unless something broke.

The sheared pin would look fine until you actually try to remove it or you pull the flex joint away from the hydro's input.

Since a sheared drive shaft pin would be the easiest to fix, I'd check that first. You won't know for sure unless you drive it out and inspect it.

[Alvy]

Originally Posted by sawdustdad

Is it possible that the spirol pin through the drive shaft at the hydro input shaft has sheared? It would not be apparent, and the sheared pin might catch occasionally and the drive shaft will turn the hydro input for a while, until under load, it releases and the drive shaft spins without turning the hydro? It might tend to catch in reverse.

I suspect (though Jon is much more knowledgeable than I) that the worn out hydro situation would not be something that would appear suddenly. Nor would the loose/faulty hydro linkage unless something broke.

The sheared pin would look fine until you actually try to remove it or you pull the flex joint away from the hydro's input.

Since a sheared drive shaft pin would be the easiest to fix, I'd check that first. You won't know for sure unless you drive it out and inspect it.

I was going to suggest this exact thing first. Heat building up from slipping a lot then expanding and catching sounds possible