Need help...I have a 312b escalator. Im having some issues with the tracks function. When the machine is cold everything works great. As the oil gets hot the tracks won't steer. Goes forward and reverse but will not turn independent. Any suggestions
Reseal the swivel would be my first thought.
if reseal don't help, make a case drain motor leak test
Follow the oil and test components. Start with clean oil in tank and suction filter free of debris. Oil gets sucked over to pump. Check pump pressures. If within spec, move to Main Control Valve. Check pressures. If within spec, check at travel motor. If ok, check case drain on travel motor. Oil then returns to tank. I recommend starting at the pump. If your pump is not building and holding pressure, then it doesn't do much good to troubleshoot any other component.
Machine travelling & turning fine when the oil is cold and having steering issues when the oil is hot are classic symptoms of oil bypassing in the swivel. The OP reports no hydraulic issues other than that. Reseal the swivel as a first step.
I agree with Nige, to stop having track issues its a good idea to reseal swivel every 6000hrs, If your machine is around the 10000hr mark and never been resealed then definitly do the swivel, you will be suprised how good the machine works after doing this