Bleeding the closed loop PT drive system

[NJBill]

Kent,
Don't bother about your Manual being inTennesee, in all probability it is of little use to you. I have one more circuit to trace and redraw, to complete MY CIRCUITS FOR MY 422, other peoples may be different. The ones I have in my Manual will be trash pretty soon.
I have taken as much time as it needs to find out exactly where each hose originates, and terminates. You could be in for some surprises.
I already apologized to JJ for giving him a copy of a system from my manual. I have not yet posted all my corrected drawings. There is apparently no
set procedure for installing the hoses.
I have four circuits in my manual, so I am drawing four new ones. ALL circuits finish up at the return ports of the tank. The last one ( part of the tilt/lift circuit )comes from the Sauer-Danfoss valve bank, goes to the cooler, and then to the return port on the tank.
I call it "trying to do things right", as one of our other auto mechanic colleagues will confer, it's just something we do, so that nobody gets killed or injured.
You will enjoy tracing the hoses, it's tough but well worth the effort.

 

[J_J]

Kent,
Don't bother about your Manual being inTennesee, in all probability it is of little use to you. I have one more circuit to trace and redraw, to complete MY CIRCUITS FOR MY 422, other peoples may be different. The ones I have in my Manual will be trash pretty soon.
I have taken as much time as it needs to find out exactly where each hose originates, and terminates. You could be in for some surprises.
I already apologized to JJ for giving him a copy of a system from my manual. I have not yet posted all my corrected drawings. There is apparently no
set procedure for installing the hoses.
I have four circuits in my manual, so I am drawing four new ones. ALL circuits finish up at the return ports of the tank. The last one ( part of the tilt/lift circuit )comes from the Sauer-Danfoss valve bank, goes to the cooler, and then to the return port on the tank.
I call it "trying to do things right", as one of our other auto mechanic colleagues will confer, it's just something we do, so that nobody gets killed or injured.
You will enjoy tracing the hoses, it's tough but well worth the effort.

NJBILL,

MARRT sent me a copy of the hyd circuit for an 1850. It only had a basic circuit, and left out many details. If you sent me something on your 422, I did not receive it. Pt is about the worst I have ever seen on letting the owners know how the Pt machines work. It should have a good theory of operation, and complete wiring and hydraulic schematics. It's a stinking shame, that if we can't figure things out, we have to call Terry. They must think that most of us are stupid , and that we can't read a schematic. Their motto seems to , sell it, forget it, and if you need parts, only call us if you have a min $50.00 order. They would never get a contract with the military. because they would have to supply to many details, and write very detailed manuals. Pictures, forget it . They have no idea that we live in a digital age and pictures are every where. They say that a picture speaks a thousand words, but PT doesn't believe that , so they say very little. What is it that we get, a third generation copy of a Zerox copy, done on a machine that has not been cleaned in a very long while. They get a failing grade and absolutely no gold stars or smiley faces for documentation.

 

[toy]

JJ,

I don't have the hydraulic diagram handy -- the Owner's Manual is with the PT down in Tennessee.

toy,

Thanks for the tips. I'm leaning toward draining the lines to the wheel motors, to try getting rid of any metal particles that may be in there. Hopefully this is a "one time" opportunity to clean any contaminents out.

If in this motor change out you do loose a good portion of the hydroulic oil in the tank it might be a good time to cansider completly changing the oil and doing a good clean up of the hydroulic tank.

 

[RegL]

If in this motor change out you do loose a good portion of the hydroulic oil in the tank it might be a good time to cansider completly changing the oil and doing a good clean up of the hydroulic tank.

I just changed out the left rear wheel motor and was surprised that very little fluid was lost, even though I didn't plug the hoses and they were disconnected for two or three days. I just tied them facing up the best I could. Also I didn't bleed the system when done installing the new motor. I haven't noticed any ill effects yet after a couple hours of loader work. I'm not giving any recommendations here, just info.

 

[KentT]

If in this motor change out you do loose a good portion of the hydroulic oil in the tank it might be a good time to cansider completly changing the oil and doing a good clean up of the hydroulic tank.

I just changed the oil, going to Amsoil 20W50 synthetic, about 100 hours ago -- perhaps a bit more. Don't really want to repeat that $200+ expense if it isn't necessary.

 

[toy]

I just changed out the left rear wheel motor and was surprised that very little fluid was lost, even though I didn't plug the hoses and they were disconnected for two or three days. I just tied them facing up the best I could. Also I didn't bleed the system when done installing the new motor. I haven't noticed any ill effects yet after a couple hours of loader work. I'm not giving any recommendations here, just info.

I have not had any problems with my machine that would require changing out any parts such as a wheel motor [knock on wood] so to give first hand knowledge on that particular change out I couldn't , but on other machines when taking hoses loose I've seen oil gush out and everyone trying to find something to plug the hose or get the hose tightened back up in a hurry. Tying up the hoses is a good idea to raise up the hose ends above oil level, but not looking at it at the time I wrote the response I couldn't remember if there was enough slack to do that. This is what I like about this forum when we are faced with a major repair we can get good general advice and if anyone has done the job first hand they can give an accurate idea of what to expect and things that they would have done different if doing it again. That way we can get ready to do the job with general suggestions in case something goes wrong and a more precise description of how a job was done successfully. This way when we start a job we will be more prepared more alert and can work more productively to complete job with success.

 

[toy]

I just changed out the left rear wheel motor and was surprised that very little fluid was lost, even though I didn't plug the hoses and they were disconnected for two or three days. I just tied them facing up the best I could. Also I didn't bleed the system when done installing the new motor. I haven't noticed any ill effects yet after a couple hours of loader work. I'm not giving any recommendations here, just info.

In my first post in this thread I thought I had neglected to mention tying up the hoses above the oil level but in rereading it I did mention it. I knew that I had thought of that but I didn't know for sure if I mentioned it , sometimes my body is present but my mind is lost in space. Scotty you can beam me back up now.