Re: Hydraulic Widow help
Posted by HH56 on 2021/11/16 21:32:49
What year? Prewar operation is different from postwar and when you mention a replacement pump, what kind as some of the aftermarket top pumps may not have the pressure needed to operate the windows.
For a partial answer, on the original pumps there is a solenoid switch on the pump similar to a starter solenoid and operated by the window and top switches that turns on the pump. A solenoid valve at each window cylinder is also activated simultaneously by its window switch to allow fluid to only pass in or out of the selected window cylinder.
Prewar, there are two solenoid switches as the pump runs both in up or down operation to either supply pressure to raise or when lowering, runs the opposite direction to help suck the fluid out along with it being expelled by a spring pulling the window down. Postwar, there is only one solenoid switch as the pump runs only to raise the windows. When lowering, only the window solenoid valve opens so a large spring can pull the window down and send the fluid back to the reservoir.
Believe the prewar tops were vacuum operated but for the postwar top, the top control assy has an electrical switch section to operate the same solenoid switch used for the windows. Difference is the pump is used to supply pressure both when raising or lowering the top. Fluid is directed to the top or bottom of the top cylinders by the mechanically operated hydraulic directional valve portion of the top control switch assy. The windows are unaffected when moving the top because their solenoid valves do not open and fluid cannot get to the cylinders.
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