1990 740 - ABS pump won't shut off

[acurry]

Hello. My 1990 740 Turbo SW has an intermittent problem: The ABS pump keeps running after the engine is stopped.

Usually - but not always - the ABS warning light has come on while running.

I can almost always hear it running as I get out the car. I open the hood, pound the pump lightly with my fist one time, and the pump stops.

One time, though, I didn't hear it, and it drained the battery completely overnight.

Do I need a new pump?