case 1840 how do i check pressures for left drive pump

[glenndoriott]

I have a case 1840, left drive motor bolts come loose and busted drive motor, replaced with new motor, now left side has very little power output. I have tried two different drive motors so problem is in pump. Before the motor broke this machine was very slightly slower driving on left side but not bad. something happend when the motor broke or during the repair process. i dont think any contaminants got into the pump system,but anything is possible. how do i check pump pressures and what should pressures be. I have already pulled some of the valves on the exterior of the pump and everything looked good. Is there somewhere online that i can download specs. and schematics and picts and other info. Thank You for any and all info. Glenn

 

[Kurt]

I am also going though growing pains finding info on this system, but I have found that the center raised part of the pump is the charge pump, the port on the top of this is suppose to be giving 320-340+ psi at full throttle, this supplys pressure to the high pressure pumps one forward and one rearward, (next to the engine), the one closest to the engine provides power to the right side, and the pump furthest away from the engine is for the left side. There are four testing ports on the top of the pump two on each side of the charge pump port the two furthest away from the engine will be for the left drive motor, the pressure should be above 1000 psi to 3000 psi, when the control lever is engaged for that port, when the control lever is not moved there should be no pressure, the amount of pressure is dependent on throttle position. I would check to see if you have a air lock in the hyd lines to the motor, bleed the hose for the left side. I haven't been able to find a parts breakdown for this pump, but if you find one please let me know. Kurt

 

[kecamml]

I am also going though growing pains finding info on this system, but I have found that the center raised part of the pump is the charge pump, the port on the top of this is suppose to be giving 320-340+ psi at full throttle, this supplys pressure to the high pressure pumps one forward and one rearward, (next to the engine), the one closest to the engine provides power to the right side, and the pump furthest away from the engine is for the left side. There are four testing ports on the top of the pump two on each side of the charge pump port the two furthest away from the engine will be for the left drive motor, the pressure should be above 1000 psi to 3000 psi, when the control lever is engaged for that port, when the control lever is not moved there should be no pressure, the amount of pressure is dependent on throttle position. I would check to see if you have a air lock in the hyd lines to the motor, bleed the hose for the left side. I haven't been able to find a parts breakdown for this pump, but if you find one please let me know. Kurt

 

[CASE 1840]

I am also going though growing pains finding info on this system, but I have found that the center raised part of the pump is the charge pump, the port on the top of this is suppose to be giving 320-340+ psi at full throttle, this supplys pressure to the high pressure pumps one forward and one rearward, (next to the engine), the one closest to the engine provides power to the right side, and the pump furthest away from the engine is for the left side. There are four testing ports on the top of the pump two on each side of the charge pump port the two furthest away from the engine will be for the left drive motor, the pressure should be above 1000 psi to 3000 psi, when the control lever is engaged for that port, when the control lever is not moved there should be no pressure, the amount of pressure is dependent on throttle position. I would check to see if you have a air lock in the hyd lines to the motor, bleed the hose for the left side. I haven't been able to find a parts breakdown for this pump, but if you find one please let me know. Kurt

Your machine uses a Sauer / Sundstrand M 46 ( 40 series ) pump and Danfoss OMT 400 motors. The motors are also under the Sauer / Sundstrand banner. . . . . . . . . . . . . . . . . . . . . .. . .. . . . . . . Go to the Sundstrand site and download the service manual, it will give a diagram as how to check pressures. You will need a -6 SAE ORB fitting to check pressures. Be aware unless you load the machine, you won't see much in the way of drive pressures. If the other side works, the charge pressure is likely OK.