My friend got a cat 966h sn/a6d01818 28000hrs When lifting the boom , it have lost is hydraulic power The pilot pressure is 540psi But the load sensing signal relief valve , is 1600psi As SIS procedure , i've tried to adjust but nothing change Brand new hydraulic filter , open the used one , were clean Just think i's the compensator valve on the pump ? Anyone have a better idea?
A6D S/N prefix is a 966H, not 980H. Can you confirm which model you are talking about, it could be important.
My bad , you're right its a 966h
OK, so this machine has full electro-hydraulic controls. 1. Have the joystick position sensors been calibrated.? 2. Have the proprotional solenoid valves in the main controi valve been calibrated.? 3. Has the margin pressure on the implement pump been tested.? Lastly how did this issue develop.? Slowly over time or literally good one day, bad the next.?
No the joystick not been calibrated No the main control valve neither No the margin pressure not been test led cause it need a diferential gauge but dont have one here Literally good one Day and bad the next day
I think I would do all the calibrations first, just to rule them out. Then it looks like you'll have to find a differential pressure gauge from somewhere.
Just finished a 950h that was slow. Lift arm position sensor was bad. Replaced it and recalibrated and it came alive. I recalibrated it with et first and it sped up but got jumpy at the bottom of stroke. You could see the numbers jump around with ET because the sensor was bad. The ecm drastically slows the flows down when it either thinks the cylinders are about to the end of their stroke or it doesn’t know where it is in the stroke. I would definitely calibrate and verify the sensors are working properly before doing anything else.
All the calibration have been done but still the same issue
While ET was hooked up to do the calibrations did anyone think to check the operation of the lift & tilt linkage position sensors as mentioned by @couesaddict above, or look for any other sort of Active Diagnostic Codes.? That really ought to be the next step if it hasn't been done already. Diagnostic Codes can be accessed via the Monitor Panel without needing ET, although you will need it to see how the lift/tilt position sensors are performing in real time. For the correct procedure to access Codes it needs the machine Serial Number so we can see exactly what type of Monitor Panel you are dealing with.
There'se no other active code and yess i've check the operation of the tilt and lift sensor , everything was fine
How exactly did you do that.? Do you have access to Cat ET.?
Yes i have access to CAT E.T.
Thank you. Just checking how the sensor signal was monitored. Which also brings up a thought. What were the minimum & maximum duty cycle values that you saw for both lift and tilt linkage position sensors.?