Webster Hydraulic Fan Motor

[cmillsap]

(09-22-2013 00:23)davidbrady Wrote:  Tommy,

There is a Webster Relief Valve in your hydraulic circuit. When neither the power steering nor the hydraulic fan is calling for pressure the relief valve redirects fluid back to the reservoir. I'd look closely at this valve. If it's failing to open pressures could build to excessive and damaging levels. Here's a schematic of your system. In the drawing item number 37 is the Webster Relief Valve:



My theory is that the pump worked fine as long as you were moving the steering wheel, when you stopped the pressure built and the shaft failed. When you stopped, the pressure had no where to go most likely due to a faulty Webster relief valve.

David,

Is Item #34 the solenoid valve? It appears that is the only item in the fan circuit with wires. If it is and is somehow blocking the flow of oil to the relief valve, the pump (being a positive displacement pump) will dead head at it before the relief valve and cause the system to be over pressurized and blow the pump shaft.

We have no idea how that solenoid valve is designed. We don’t know if it is possible for it to completely block the fluid flow by the position of the spool. I think we need to know more about that solenoid valve and how it works.

Chuck