ABS Solenoid Valve

I've got a 95 Blazer (T10), 4x4, 4-door, auto, with 4 wheel anti-lock brakes (4WAL).

The ABS light is on and the previous owner told me that when the shop diagnosed it, they found that the pump or solenoid valve hangs up, and if you hit it with a hammer, it will pop free. Reset the computer and the ABS operates normally until the pump / valve hangs up again.

I trust the previous owner because I know him personally.

My question is: can I replace the faulty pump / solenoid by itself, or do I need to replace the whole computer assembly with all four pumps / solenoids?

Has anyone successfully replaced just one faulty pump / valve?

Thanks in advance.

Recycler

Its sold as a whole unit or modual. try findin one from a boneyard.