1532 Hyrostatic problem/question.

[k0ua]

Makes sense. So TSO's tractor is up there with ares then? or more. Man 4975psi is a lot of umpa.

I would bet real money that TSO's tractor hydrostatic transmission relief pressure is somewhere near what ours is. Around 5000 psi.

 

[radrock]

I would bet real money that TSO's tractor hydrostatic transmission relief pressure is somewhere near what ours is. Around 5000 psi.

Probably, my tractor is pretty small compared to his. It's only 26 HP. The pressure relief valve that I had to have fixed was on the joystick valve and is called the safety relief valve. My three point hitch would not raise because of this.

 

[radrock]

Yes, I found that that relief valve takes care of the whole system, but I did see another one on the 3 point. I had to break the paint like you explained in your thread. I took the valve out, cleaned it up and started at 0 psi. When the screw was all the way out, nothing worked.

Can you post any pictures of these locations?

 

[jmarx82]

I would bet real money that TSO's tractor hydrostatic transmission relief pressure is somewhere near what ours is. Around 5000 psi.

Ok, So why would the tractor not move when there relief valve I messed with was all the way out?
I am out of town for work now. I can post some pics when I get back.

 

[radrock]

I wish I understood all of this stuff myself. I looked up your tractor at AGCO Parts Books. The 1529 and 1532 are the same. Mine is different however they both have a pressure relief valve on the side of the transmission someplace. Here are two screen shots I took, one of the Transmission and the other of the Hydraulics For your three point hitch. Maybe your tractor would not move when you backed off the pressure relief valve because it caused an oil dump. No pressure or a free flow thru that may have caused it to loose all pressure everywhere else on the system. I am not mechanic by any means and don't really know what I'm talking about. It is crazy stuff. But if your tractor is operating correctly by what you did I would by all means leave it that way. Make sure it is not getting hot or anything. You mentioned earlier that your tractor would not spin the wheels in Mid-Range on the snow and ice. I am positive that your tractor should spin the tires on a slick surface.

 

[k0ua]

Ok, So why would the tractor not move when there relief valve I messed with was all the way out?
I am out of town for work now. I can post some pics when I get back.

One thing I thought of is perhaps the Massey does not have a charge pump internal to the transmission. The charge pump makes up the leakage losses in the main pump. On my Kioti the charge pump is not internal to the transmission either. It is a circuit that takes its input off of the power steering section of the implement/power steering pump. This is the only thing I can think of. The hydrostat on the Kioti is made by Kanzaki. I wonder if the Massey(made by Iseki) could also use a Kanzaki transmission with this setup for the charge pump? But trust me on this the Main pump which is 1/2 of a hydrostatic transmission has very high relief pressures, usually far higher than the 2500 or so that the implement/power steering pump up on the side of the engine. The other 1/2 of a hydrostatic transmission is a hydraulic motor.
And as I stated and Murph confirmed the relief valve pressure on our Kioti's is 4975 lbs. as I would expect any tractor of similar size to be.
The relief pressure on my implement pump is 2645 lbs or there about's.

But more to the point the PRV on the implement pump was not what I thought the problem was, and if the charge pump circuit comes from the implement pump and its pressure was set low, perhaps this could explain it. I don't know. We need someone that works on these machines every day or an engineer that designs them to confirm this. In any case if you were able to solve the problem by increasing the relief pressure on the implement pump then good deal, but it is still hazy to me how that fixed it unless my supposition about the charge pump is correct. It is all I can think of. Sorry for any confusion

 

[k0ua]

I am positive that your tractor should spin the tires on a slick surface.

I agree. My Kioti will spin its tires on a gravel or dirt surface in MED range easily and that includes the fronts at the same time. It will not do it in HI range at all. The PRV just opens and the transmission just whines and the tractor does not move.

 

[k0ua]

Here is an old thread with a better description of an hydrostatic transmission's charge pump and what it does. The charge pump pressure on my Kioti is 255 psi. Again this pressure is derived on the Kioti from the power steering circuit, as there is not actual charge pump in the transmission like some design's use.

http://www.tractorbynet.com/forums/...nt/211669-what-hydraulic-charge-pressure.html