I have an older Bobcat 753 F Series with foot control only. Lately my lift and tilt both freeze up for various amounts of time. Right now I have the Backhoe attachment on and it works fine no problem with the auxiliary controls. But i cant get the backhoe off because the lift and tilt seem to pressure up a little but won't move enough to undo things. In the past few weeks after slamming down the seat cage they would work for a shot time while I have the bucket on, but still occasionally freeze until I hit some bumps and then they start working. They are both locked at the same time, not one or the other. I assume it is in one of the valves on the main control block, but which one or could it be something else?
Does it help if you turn off the aux. hyd's that run the backhoe? Maybe cycling the aux. hyd's a few times with the engine off may help.
I've tried that many times and I've turned the key to the left to get the hydraulic pressure out of the system.
What are the symptoms of part number 6664850 (lift lock valve assembly) going bad?
I think I found the problem. Debris getting under the seat so that the seat switch wasn't working or bad wires to the seat switch.