Changed T1400 HST fluid now it won't move

[fruitcakesa]

I changed the diff fluid with SUDT and put 10-30 in the HST.
I also cleaned the HST filter.
Now it won't move at all.
Does it need to be bled or some other procedure after a fluid change?
Any ideas?

These are the recommended fluids for the trans. according to the manual I saw online.
From the manual:
Hydrostatic Transmission 0.60 US qts. (0.57 L) API service CD SAE 10w-30

Transmission Case - T1400H 1.9 US qts. (1.8 L)
- T1400 2.7 US qts. (2.6 L)
-------------------------------------------------------------------------------------
Multi-grade trasnmission fluid or gear oil SAE #90. The fluid listed below or equivelent are recommended.
Kubota - UDT Hydrostatic transmission fluid
Shell - Donax-TD Donax-TM
Mobil - Mobil Fluid 350, 423
Exxon - Torque Fluid 56

 

[the old grind]

Did you 'pre-fill' any of the filters or install them 'dry'?

 

[fruitcakesa]

The only filter is a tubular, fibrous unit that is in its own fluid filter chamber.
This is not like the canister hydro filters on the bigger tractors.

 

[the old grind]

It seems as though your pump has lost prime, and/or can't recover from the system being drained. If you're confident that any/all connections went back together tightly can you pressurize that system by using a rag over the reservoir or fill cap with air nozzle? (rag assures <15 psi) An exposed suction leak might ooze at that, one not yet seen perhaps becoming apparent if the rag seems to be very tightly held and pressure is not pushing it off.

Can you add pics of any components in place? There may be something, some way to 'bleed' that's in a manual that you don't yet have.

(waiting for anyone who don't need pics to chime in)

 

[fruitcakesa]

Jacked it up and ran it while moving the hydro pedal F&R.
About a minute or so later, the wheels began to turn so I continued rocking the pedal for another minute and voila, it was fixed.
I also shortened the HST pedal adjuster 2 turns and now it is better than before I did the change.
Thanks again for the tips.

 

[fruitcakesa]

update:
Took it out mowing and after about 15 minutes , the tractor stopped moving with almost no HST pedal engagement.
I was able to limp it back to the shop and re-readjusted pedal travel which changed nothing.
I jacked it up and ran it while rocking the pedal and lo and behold, it started working again.
So, did I not get all the air out the first time? Why did it runs so well for 15 minutes.
Does anyone know the pedal adjustment and spec? I am just guessing when I do it.
The actual pedal is sloppy on the shaft maybe 1/8 to 1/4 inch play.
I tried to account for that when I made the adjustment.
Would an old belt cause this? I changed it years ago.
I will see what happens in the meantime.

 

[fruitcakesa]

Well this is weird. It will run and drive for a few minutes and then stop.
If I repeat the jacking and pedal rocking, it will run again but then stop.
I have adjusted the pedal linkage in both directions with no change.

 

[art]

Did you check the belt?

 

[fruitcakesa]

Did you check the belt?

The belt was replaced some years ago but it is not cracked or slipping[no smell of burnt rubber] but if it is stretched could that be an issue?

 

[fruitcakesa]

I put a new drive belt on in hopes that a worn belt was the answer...not!
It is just a bear to purge all the air out of the hydro unit.
It took about 10 actual purges, jacking the machine and rocking the hst pedal till the wheels began turning. Do it again and again and again etc until it is completely bled.
The pedal travel adjustment is very precise, there is a go/no go point in the linkage adjustment that you need to hit for the F and R functions of the unit operate fully.
Took about 6 adjustments before I got it. Now, adjusted with the new belt, it really does run better that when I got it.