Hi looking for some advice with a hydraulic problem on my 95 CAT 426b backhoe. The stick cylinder has a steady drift and will hit the ground in about 4 minutes from the most upright position. The boom cylinder also has some drift but much slower. Left side stabilizer also has a slow drift. The cylinders are all DRY and show no signs of leaking or the need to be repacked. The machine only has 2100 hrs so has had some serious down time - sitting around. Are there o-rings or seals somewhere centrally located that maybe casuing this? or a drift control valve? Any info would be great including where to get parts or service in southern VT. Thanks Matt
I would reseal the control valve
Thanks for the information. I will start with the control valve.
Run it so the hydraulics are at operating temperature and get a heavy as you can load in the bucket and extend/lift as much you can, shut it off and listen with an ear on the stick and boom cylinders for a hissing sound, if they have an internal leak you should be able to hear something. Do the same thing around the controlvalve.
Oh, and the stabilizers has a pilotoperated check valve so if that has a drift both the check valve and valve spool has to have a leak so in that case I'd put my money on a cylinder reseal