John Deere 755 Hydraulic problems

   / John Deere 755 Hydraulic problems #1  

rodgriffith

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May 13, 2008
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I have a 1987 JD 755 4x4 Hydrostatic with FEL. The FEL slowly stopped lifting as did the three point lower links and the power steering failed at the same time. Does anyone know what this could be?
 
   / John Deere 755 Hydraulic problems #2  
Looks like your hydraulic pump went bad. You should get a guage and check the output pressure.
 
   / John Deere 755 Hydraulic problems #3  
I think your 755 is similar to my 770 in that it has both a power steering and an implement hydraulic pump. So the chances of both failing simutaneously is slim. And with any mechanically problem, look at the simple and cheap options first. My guess is that the pumps, which I think use a common suction, are restricted due to a blockage on the suction side. Not sure about the 755, but the 770 and 790 have a suction screen (often found clogged with "stuff") as well as a spin on filter. To access the screen, you must drain the transmission/rear axle/common sump.

I'm pretty sure that if you drain the fluid, clean the screen, replace the spin on filter and replace the fluid with new clean tractor fluid (the JD stuff is good and fairly reasonable) you will find that the machine is back to normal. If the HST has a filter or screen, it should also be cleaned or replaced.
 
   / John Deere 755 Hydraulic problems #4  
I'm quite confident just one hydraulic pump on the 755, but that doesn't necessarily mean the pump went south. Attached is list of "things to check" on this model tractor.
 

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   / John Deere 755 Hydraulic problems #5  
does anybody know if the jJD755 has a screen in the hydraulics and if so where it is
 
 
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