Anyone experience ABS Pump failure?

I might be wrong, have been before but it sounds more like the master cylinder to me! "Hard to argue with someone that can put a hand on the car and test the system when we can't though"! How does it do under hard braking, pedal feel ok then? If so, that's another symptom of a failing mast cyl! When push on pedal easy, fees like it is going down to far. When push on pedal hard, feels ok = master cylinder! All day long! Night too. That's my story and .......

If one of the dump valves in the ABS controller is leaking, fluid will be bled off from what ever wheel that valve controls and it will flow into an accumulator in the assembly. The accumulators have rubber caps that can be removed, and you can straighten out a paper clip and stick it through the hole and touch the bottom of the accumulator piston. Then have an assistant push on the brake pedal so that it fades, and if the ABS controller is bad, the piston will push the paper clip out.