Bleeding ABS Pump

[Larry Herman]

Just read it all again, it makes perfect sense.  You bleed the brakes normally.  All fluid passes through the ABS unit (and past the closed  ABS valves) no problem.  Imagine that the system is set up like a "T" with the fluid going through the T, and the ABS valve on the branch.  When that valve opens, it dumps pressure to the specific brake line where the wheel is locking.  That releases pressure on the brake caliper and prevents lockup.

Where the "dumped" fluid goes in the ABS is still a mystery to me, but safe to say that is where the trapped air is, and that is why you would need to cycle the ABS unit AS you bleed the fluid through.  Again, the need to bleed tha ABS unit itself is very rare.