Downeastah,
I would put a pressure gage on the pump and monitor the pressure. What you see will help diagnose the problem. Almost sounds like you are running out of fluid to pump, and the gage will tell you that. You could have a relief valve stuck open, or sticking intermittently. If there is nothing to stop or slow the fluid path, you will read very much pressure.
If you have the pressure and volume, say to a valve, the fluid will go to the valve, and back to tank, very little pressure. When a spool is activated, the flow is directed to a cylinder, or motor, and work is done, and you can read the pressure, could be any pressure between say 500 psi up to say 2500 psi or whatever the pump max pressure is. . In the power steering, same thing, the fluid goes to the steering valve, and back to tank. When activated, the fluid pushes on the cylinder to turn wheels, etc, and pressure can be read. The pump will try and push the fluid against anything in it's path, and when it can not push any more, the excess goes through a relief valve and back to tank. So a pressure gage at critical locations, can diagnose just about all your problems.. Below is a similar situation.
IH 574 hydraulic problem
I have an international 574 with hydraulic problems. I have changed pump with gaskets and filters but still after about 10 min or so use, the hydraulics seem to fill with air. the 3-point arms wont lift, the stearing gets tough, and I just dont seem to have any pressure. for the first few mn everything works great. plenty of pressure and volume. any suggestions that I could try would be appriciated.
Thanks
There is a transfer, lubrication pump that moves oil from one section of rear frame to the other. Sounds like that pump is not working or screen on it is plugged, most likely with derbris from the parking brake band. You can clean screen by removing plate on right side of rear frame. When tractor is not running the fluid will equalize in the two sections but when pump is moving oil it is not able to get back into the section that the pump is in fast enough. Some place to start anyway.
I have a I/H 454 that has no 3 point lift and no remote power pressure. p/s works but noisy. fluid is full cleaned and checked valve under seat as I have heard the unload valve sticks but this did nothing anyone have an idear? ps anyone know if there are any filters and where they may be thanks Tom
I don't have a IH 454 and I will be the first to admit my mechanical knowledge can be weak. However on my IH 656 there is a plate on the right side probably 6" x 10" inside of it is a hydraulic filter.
I would also suggest that you go to your local IH dealer and buy a hydraulic filter for your 454. They will have a diagram in the parts book or on the computer showing you right where it is. Good luck.