QuestionI just acquired a Case-IH 695 tractor with hydraulic issues. I was able to drive it onto the trailer (although the power steering didn't work) and when I got it home, before unloading it, I drained the hydraulic fluid, changed the filter, cleaned the screen and refilled with CaseIH hydraulic fluid. The looked better than expected and got about 8-9 gallons out of it. There were some metal shavings on the screen, but nothing out of the ordinary. I unloaded it and shifted it back and forth a few times and after about 5 min, the power steering started working and I drove it around the farm another 15min or so before parking it. Before shutting it down, I checked the 3pt, pto and hyd remote valve and everything seemed to work as expected so I shut it down. After sitting for an hour or so, I started it up to put it in the barn and the power steering wouldn't work again. Is it possible the filter needs changed again? The guy I got it from says that after 20min or so of use, it would stop and you'd have to let it cool down before using it again. I've read some of your other posts suggesting the multiple control valve or the regulator valve. I've got the parts manual, but no service manual so I'm a little unsure of where to check pressures to properly diagnose the problem(s). I would consider myself an intermediate car mechanic, novice tractor/equipment mechanic and I have worked a little on industrial hydraulic systems. The next thing I was going to do is remove the regulator valve, disassemble and clean the spool. If that doesn't work, I'll remove the mulitple control valve but I'd like to be able to closer pinpoint the problem before getting this far involved. I'm I heading in the right direction, or? Any help would be greatly appreciated. Thanks in advance for any light you can shed.
AnswerHello,
I doubt that the filter would plug up again that fast. Usually, if you have to let it cool down to get the hydraulics to work, the pump is getting pretty weak. As the oil warms up it thins out and the pressure drops off. The easiest way to check the main hydraulic pressure is to plug a gauge into the remote couplers on the back. A repair shop can also plug in a flow rater and record the flow at different pressures to get a better diagnosis. Recheck the oil level on the dipstick and with the oil warmed up, if the flow drops by more than 10% at 1500 psi compared to what it is at no pressure, then the pump is worn out. Without a flow rater, you can compare the pressure you get with cold oil compared to the pressure you get with the oil hot and it will give you some indication. The pressure at the remotes should be at least 2000 psi. If you get far less with the oil hot, the pump is probably weak. If the pressure is low all the time, possibly the relief valve is bad, there is a suction leak, or there is a blown gasket or o-ring in the multiple control valve. To check steering pressure, tee in a gauge at the steering cylinder supply hose fittings. There should be at least 1400 psi. Turn the steering wheel all the way to the end and watch the gauge. Remember that when checking with only a gauge, you can have pressure but not enough flow to do the job, so that's why a flow rater is a better way. The steering takes about 3 gallons per minute and the steering priority valve is supposed to make sure it gets that before giving oil to the other functions. The main relief valve, steering relief valve, steering priority valve, pto valve, and oil cooler bypass valve are all located in the multiple control valve in front of the left rear axle. It would be too hard to tell you which one is which without being able to show you. You can see a breakdown of it at caseih.com and click on parts, then online parts search. Enter your model in the search box, then select your model from the results. Go to the hydraulic section and you can see pictures with the part numbers. The pump is located inside the transmission on the back side of the multiple control valve.
