I have a john deere 4440 that the hydraulic pump has been replaced 3 times in less than 100 hours. The last pump lasted less than 20 hours before it blew the seal out. I plugged a pressure gauge in the rear remotes. In the left bank of each set the gauge would go to neutral and stay at o psi. In the right bank the gauge would go to zero then go up to 2200psi and stay there unless you moved the lever a small amount. All linkage was unhooked before I tried this. Is this how the hydraulics work on a john Deere.
Chrz farms
You're leaving out a lot of information here. Who replaced the three pumps and why? What else was checked or done to establish the need for that? Was your recent pressure check done before or after said seal "blew out"?
While testing standby pressure at remote couplers may be the easiest method, it does put you at the mercy of the valve's operating condition. In your case it might be wise to tap in somewhere ahead of the valves, and possibly be prepared to disconnect and isolate them to what if anything changes elsewhere in the system.
While testing standby pressure at remote couplers may be the easiest method, it does put you at the mercy of the valve's operating condition. In your case it might be wise to tap in somewhere ahead of the valves, and possibly be prepared to disconnect and isolate them to what if anything changes elsewhere in the system.
Ditto what Fedup stated. Over the yrs since I've been diagnosing hyd problems many hyd pumps have been replaced only to determine that the replaced hyd pump wasn't at fault. I agree one should check hyd pressure in front of pressure control valve which could be blocking pressure to SCV's. What was the symptoms(problems) of the 2 pumps previously replaced?
SCV breakaway coupler should not have pressure until control lever is moved in correct direction to send pressure oil to the corresponding orifice. Pressure should remain on gauge when lever is returned to neutral position & gauge should return to zero when control lever is moved opposite direction to apply pressure to opposite orifice in breakaway coupler.
SCV breakaway coupler should not have pressure until control lever is moved in correct direction to send pressure oil to the corresponding orifice. Pressure should remain on gauge when lever is returned to neutral position & gauge should return to zero when control lever is moved opposite direction to apply pressure to opposite orifice in breakaway coupler.
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