I understand how ABS works, and I understand that the ABS modulator removes the brake pressure to the locked up wheel(s) by activating solenoids and then re-applies it. But how does it release that pressure and how does it re-apply that pressure? What goes on inside the modulator? Any info would be very much appreciated (diagrams would be even better for my feeble mind).

Thanks in advance.

 

There's an electric motor driven pump to reapply the pressure. Releasing the pressure is easy you just open a valve around the master cylinder and allow some fuild to flow back to the master cylinder.

For an idiots guide see how stuff works

And when I say idiot I didn't mean you, I meant it's written for Mercans so while it is right in the basic principles take some of it with a hefty dose of scepticism.