Hydraulic problems Power Trac 1850

[PowerT1850]

Hi,
I am from Sweden and a new user on this forum. Have hydraulic problems. It run slow when I bought it and I have repaired one wheel engine and tested.
Should move some gravel when it stopped with a "jumping pedal". Not moving forward or backwards. The lifting and steering works but not so strong and a little slow to. I think it is a PT 1850 early modell and have a Kubota 4-cyl engine. Can not se what the mainpump have for brand or modell. Anyone that can tell?
See pictures. Need also the circuit for hydraulic to trubleshot.What can be wrong?
I am in a hurry because the snow is falling and I have nothing to move it with!!

 

[J_J]

You should check some pressure with a hyd gage and see if there is a loss somewhere.

I also have one of the older Power-tracs, with a Ford Industrial 45 HP gas engine.

I have never seen or heard about a PT with a Kubota in it.

Anyway, my PT has three pumps, the large pump is a variable speed hyd pump, and a piggyback pump is on the back of that pump for the PTO.

My steering and lift is from a pump driven by the fan belt.

There are some members that have 1850, but not that old.

Perhaps call Terry at Power-Trac and tell him what you have and they might have a parts manual.

http://www.power-trac.com/

 

[PowerT1850]

Hi JJ,
Thanks for quick reply. I have spoken to Terry last week and send several pictures. He should see if he could help me, but no answer.
I will take more pictures and more questions will come on this forum.

PowerT1850

 

[J_J]

I have referred your post to other members that have an 1850.

http://www.tractorbynet.com/forums/power-trac/

 

[ponytug]

I don't have your model, so it is a little difficult to diagnose, but it sounds like your tram pump (Variable Volume Pump) has an issue. That would be the leftmost pump in the series on the right photo. Hydraulic feedback at the pedal is not normal.

I am sorry not to have specific suggestions.

All the best,

Peter

Hi,
I am from Sweden and a new user on this forum. Have hydraulic problems. It run slow when I bought it and I have repaired one wheel engine and tested.
Should move some gravel when it stopped with a "jumping pedal". Not moving forward or backwards. The lifting and steering works but not so strong and a little slow to. I think it is a PT 1850 early modell and have a Kubota 4-cyl engine. Can not se what the mainpump have for brand or modell. Anyone that can tell?
See pictures. Need also the circuit for hydraulic to trubleshot.What can be wrong?
I am in a hurry because the snow is falling and I have nothing to move it with!!
View attachment 291351View attachment 291352View attachment 291353

 

[J_J]

Have you changed filters?

The charge pump pressure has to be correct also, and should be pumping about 10 percent of VSP pump volume .


Relief valves in the pump might be fouled.

Perhaps the trouble is in the wheel motor circuit.

I believe the wheel motors are in a series /parallel configuration.

If that is true, I believe the 3000+ psi high pressure is developed across two of the 1500 psi motors.

 

[wdchyd]

First thing I'd do is lift the tractor off the ground and see if both wheel motors are going in the same direction.....if not, then the drive motors are fighting themselves and timing is wrong internally in the repaired drive motor or the motor hoses are on backwards, or the motor work was done wrong

If not, then I'd remove that hydrostat pump and look at the internals for obvious problems

Either way it is always best to elevate the drive wheels when doing repairs to hydrostat systems for your own safety......these things sometimes have minds of their own....

 

[PowerT1850]

First thing I'd do is lift the tractor off the ground and see if both wheel motors are going in the same direction.....if not, then the drive motors are fighting themselves and timing is wrong internally in the repaired drive motor or the motor hoses are on backwards, or the motor work was done wrong

If not, then I'd remove that hydrostat pump and look at the internals for obvious problems

Either way it is always best to elevate the drive wheels when doing repairs to hydrostat systems for your own safety......these things sometimes have minds of their own....

Thanks for troubleshooting help. I will test to lift and see if it moves. It worked at first and then suddenly stopped, so connection is not backwards. The back and forward drive is working with electrical valves. Maybe this is something wrong with?
See attach images. Is the small pump at right side on Kubota engine a hydraulic pump for steering. Is the dualpump with axial pistons nearest engine ( drive ) and gearwheel back ( for lifting and tilt ). Anyone that can tell what brand / modell. Hard to get spareparts otherwise. The mainpump, is it difficult to repair? Expensive?
Buy a new? I am not skilled at hydraulic, but work as a tool engineer and have worked a lot with engines, in particular with chevy smallblocks.

// PowerT1850

 

[J_J]

Your machine has a serial number and Terry should be able to tell you how old it is.

Ask the parts guy for a parts list.

I would wipe and clean the pumps, and use a mirror or put the camera under the pump and take a picture.

The numbers on my pump were on the bottom.

The pump on the rear of my tram pump is the PTO pump.

Where is your third pump located?

You should be able to make up a hyd schematic by following all the hoses from point to point.

Go to your PTO connections and follow the hoses back to the pump supplying the hyd fluid. The valve controlling speed on the PTO on my early 90's machine is a lever valve.

Are you using 10W-40 motor oil in the hyd tank, or synthetic

Motor oil is the recommended fluid for hyd systems.

 

[SpringHollow]

That looks very different from my PT 1850. Some of the older models did have a Kubota engine. Terry really should be able to help but they do not seem to use email much. I sent you a PM.

It helps to rig up a pressure gauge to a Tee and some adapters to put it into various places in the circuits to see what is happening. It is really hard to get JJ to do that - he hates having people measure the pressures in their systems. (just kidding - it is one of the things he always recommends and he did so here. Because of him, I bought gauges to let me do that and a flow meter that was going cheap).

Wish I could help more.

Ken