did you check the brake pressure at the brake line on the motor?
I would put a pressure guage inline on the brake circuit and see if the pressure is dropping when it gets hot.
check the fitting on the hose connection.
diagram shows brake line to RH motor and then to LH motor.
If LH motor is releasing then something is either wrong with the brake unit on the RH motor or its not pressurizing the brake servo.
Maybe you can help me out. I have a combi C6000CB. After the truck gets hot the wheels lock up. I have to wait for the machine to cool down before it starts moving again. We replaced some relays, one of the changeover valves and the right side drive unit since the right side is the one locking up. After changing all these parts, the wheels are still locking up. Any suggestions as to which direction to go from here?
Swoop223 are you still on this forum?
if this is the CUBE model:
you can check the inching valve for sure but also check the parking brake switch and circuit at the dash controls and make sure it is correctly working, no broken wires etc. Also there may be a switch under the left pedal that operates the brake circuit.
also there is a brake valve associated with this circuit located at the hydraulic tank filter line
If a CB model then there should be a brake valve under the floor plate area (left pedal), it is not an inching valve, its either on or off. This valve is a manual valve that works the brake units on the motor assys releasing them when the pedal is actuated.
Inching valve could be an issue, look under the door in that open space with all the hoses, top left under the pedal is the valve, couple JIC stuck out of it with hoses runnin off it as well as a return spring for the pedal its self, check to make sure it's operating, i've only come across them leaking, not stickin so not much more help then that.