560 hydraulic problem

560 gas hydraulic will start squealing after running for 15-20 minutes and continues non stop. It also will not work completely after about 1 hour. Are the seals in the pump shot or is there something else going on. I check the fluid levels and it is coming out of the check plug.

No, it's not the pump. It's a blockage of sticking valve somewhere in the system. Bad pumps don't "squeal," you just don't get any pressure.

This isn't going to be an easy fix. You're going to have to tear it down and go through the entire hydraulic system to find the problem, most likely. There was a web page somewhere that detailed one person's adventure out there, if someone could post the link, that might be helpful.

This is usually caused by a plugged or restricted orifice screen assembly or worn spool valves.

The hydraulic system on the 560 is a combination of closed center and open center hydraulics. They use an open center type pump and closed center valves. The unloader valve is designed to open whenever the valves are closed or the system exceeds maximum pressure. The flow through the orifice is used to control the unloader valve. It is also ported to the spool valves. When the valves are closed there is no flow past them and the pressure builds up to open the unloader valve. Normally this results in about 60 PSI of pressure in the hydraulic system. When a valve is moved the flows from the orifice is directed to the load side of the valve and this causes a drop in pressure which will allow the unloader valve to seat. When the pressure builds to the maximum for the system the unloader valve is again unseated to control maximum pressure.

If contamination collects on the orifice screen enough to restrict the flow to less than what leaks past the spool valves there will not be enough pressure built up to open the unloader valve and the system will go on high pressure.

In your case, since it is OK when the oil is cold, I would expect to find too much wear in the spool valves so that there is too much leakage to unseat the unloader valve when the oil warms up.

Check the orifice screen assembly first. If everything looks OK there you can compensate for the worn spool valve by enlarging the orifice hole. If you drill out the hole, only go a few thousands of an inch at a time. Go just far enough th correct the problem with the hydraulic oil hot. You will need a set of number drill bits to get a small enough increment in hole size.

Interesting. I'm still fighting problems with my 2606. Mine would squeal till it warmed up in the winter or when low on fluid. A leaky cylinder will leak a lot of fluid before you know it.

Try adding an additional 5 gal of hytran to your system and see how it does. I believe the squealing is usually associated with oil starvation. Before and after doing so, get a tape measure or wood stick to make a dip stick so you can check your oil without having to pull that side plug.

Don't know if yours is the farmall or international but the pressure relief valve may be in the sump under your seat where the rock shafts are at the front right. Found a piece of metal (maybe broken spring) that would was stuck holding the ball open allowing the system to bypass.

Does yours have more than one pump on the left side and if so which one is causing the problem? Mine has a separate pump for the steering. Do you have a loader or what is it that stops after one hour?

Keep following up. These are hard to sort out.