Greetings to all!! I am a new member...Just joined, and I thought that I might pose a question.
A few days ago, I bought an older John Deere 400 backhoe, 1960's model? used it for 5 minutes (I'm not kidding!), whereupon I lost all pressure and hydraulic oil began spraying from the front (or is that rear?) pump seal. I removed the pump and found that the seal had been pressed in too far thereby blocking the overflow back to the reservoir and causing the pressure to build up and rupture the seal. But I didn't think that answered my loss of pressure problem. Sure enough, I replaced the seal and reinstalled the unit... No more leaks..Also no pressure anywhere..
I then removed and cleaned the two top and bottom plugs from the control head at the front of the pump, being careful not to disturb the adjustments too badly and reinstalled them. Now I have pressure!... Too much pressure! When I started the machine it immediately burst the large hose going into the filter assembly.. I replaced the hose ($132.00 for a 6 foot hose, OUCH ) and started the machine again. It then burst the hose next to it! Also, it is very hard to start. I have to relieve the pressure by actuating any control to be able to crank the engine.
Sorry for the long winded explanation, but my question is this: does anyone out there know how to check or reset the destroking mechanism on this machine? Could it be anything else? The pump and control head has no wires going to it, no solenoid. What I took out and cleaned did not look like anything that I have found in hydraulic schematics yet. I have already replaced all of the filters and fluid...twice. Any help would be appreciated. I cannot afford to keep replacing hydraulic hoses. Thank you very much guys!!
A few days ago, I bought an older John Deere 400 backhoe, 1960's model? used it for 5 minutes (I'm not kidding!), whereupon I lost all pressure and hydraulic oil began spraying from the front (or is that rear?) pump seal. I removed the pump and found that the seal had been pressed in too far thereby blocking the overflow back to the reservoir and causing the pressure to build up and rupture the seal. But I didn't think that answered my loss of pressure problem. Sure enough, I replaced the seal and reinstalled the unit... No more leaks..Also no pressure anywhere..
I then removed and cleaned the two top and bottom plugs from the control head at the front of the pump, being careful not to disturb the adjustments too badly and reinstalled them. Now I have pressure!... Too much pressure! When I started the machine it immediately burst the large hose going into the filter assembly.. I replaced the hose ($132.00 for a 6 foot hose, OUCH ) and started the machine again. It then burst the hose next to it! Also, it is very hard to start. I have to relieve the pressure by actuating any control to be able to crank the engine.
Sorry for the long winded explanation, but my question is this: does anyone out there know how to check or reset the destroking mechanism on this machine? Could it be anything else? The pump and control head has no wires going to it, no solenoid. What I took out and cleaned did not look like anything that I have found in hydraulic schematics yet. I have already replaced all of the filters and fluid...twice. Any help would be appreciated. I cannot afford to keep replacing hydraulic hoses. Thank you very much guys!!
JD400 backhoe hydraulic overpressurization
0 commentaires:
Enregistrer un commentaire