I did a hydraulic pressure test on my 646 this morning. I connected a hydraulic hose to my travel valve. It is connected to the port where the Allen key drain plug is. I have a 5000 psi gage attached to the end of my 4' hose. I warmed up the tractor and the 20/50 Mobil 1 synthetic oil was at 110*. I did all my tests at full throttle. If I moved the bucket or arms until they deadhead it will peak at 1400 psi. I did the same with my 3-point hitch and got the same 1400 psi. I then put the tractor in high gear and pushed against a big snow pile and all I got was 1700 psi drive pressure. I then turned the tractor around and tried it in reverse and got 1700 psi also. This is not what I wanted to see. Just to try I unscrewed the acorn nut off the back of the travel valve and turned the relief in a half turn and tested and then another half turn for a total of one turn in and still 1700 psi max. According to the manual I should be seeing 2400 psi drive pressure. I have found limited info on the adjustment of the relief so I'm not 100% sure I'm turning the correct adjustment. So do I need a new pump? Am I testing this correctly? If my travel motor was worn wouldn't pressures be different in foreward and reverse? I have double checked and my spool is traveling full travel. Am I missing anything? Any input and suggestions are wanted please. Thank You!!
Case Nut
The 3-point and loader both squeal the relief at 1400psi. Those are fine, I'm guessing because they are at lower pressure. I suspect my pump is only building 1700psi and that's all it's got.
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