John Dougherty
Bronze Member
With 20 hours on the new tractor I have a problem with the MB63 backhoe. When brand new the lever that controls the dipping of the bh (main boom closest to the tractor) made a hissing sound internally. The solution was to bump the lever back from the seated position and the sound would stop. No big deal I thought. There were and are not now any external leaks. Now at 20 hours the boom control has slack in it. Maybe a quarter on an inch measured at the plunger that is actuated by the handle and enters the valve body. The result is that additional pressure is needed for down force to dig, although it doesn't provide all that much extra pressure. On retraction, the boom will slam backwards into the 'stowed' position and the lever action is not smooth like it was originally. Operating rpm's are anywhere from 1600-1800. All other functions and movements are normal as far as I can tell. It worked when I got it other than the hissing sound. Something internal has changed in the valve body for this function of the controls. Any ideas? One more thing, ambient air temps are in the 70-80* F while operating the machine.