Kubota BH 90 backhoe-slow dump cycle

[bgWI]

My 16 month old backhoe (not used much) on the 4330 has been working fine until this AM. Digging stumps, all at once I lost "power" to open the bucket for dumping. Closing the bucket is fine as are all other functions of the two levers.

Opening the control cover, I find the levers work the valve rods fine except for the push motion to dump the bucket. No bent linkage. Travel of the bucket valve rod stops about 3/8 to 1/2 inch short of going full into the valve body (like the other valves). The pull travel does allow full extension to curl the bucket at full pressure. It feels like something physcial is preventing the rod from full inward travel, preventing full flow of oil through the valve. The valve rod resistance is there with the tractor pump running or off.

Being Sunday...Murphy's prime time for mis-function, I wonder if perhaps an O-ring curled out in the valve since all functions were fine yesteday. Any other thoughts? My hydraulic knowledge is elementary, so its off to the dealer 35 miles away on Monday....

Have a great day!

 

[JerryG]

On the bottom (opposite end) of the spool that isn't working, I would take the end cover off. It will have two small bolts or screws holding it on. Watch to make sure that you don't lose anything. There could be small parts that might fall out. It depends on the valve design. If something is damaged, that will be where it is at.
Good luck.