[TimMullen]

Has the system ever been apart or had air "sucked in"? If you have air in the ABS system, it will be very difficult to get it out. They only real way is to use an ABS scan tool (like the Lotus Scan Tool) to put the ABS into "bleed mode" where it opens (actually continuously cycles) the internal valves and and allows the fluid/air to be flushed out of the ABS.

The other possibility is that there is air trapped in the front calipers. The fluid enters the inside of the caliper at the top, crosses over to the out side at the bottom, and "vents" out the bleed nipple at the outside top. If there is air in the inboard side of the caliper, it will not be flushed out.

To flush air out of the front calipers, you have to remove the caliper, turn it upside down while bleeding fluid, then turn it back right side up and continue bleeding. The idea is to get the fluid to flow out the inside bottom (at the top as it's upside down) to the outside of the caliper. Then the bleeding will allow the air to pass out the nipple.

You may have to do the "full" bleeding of the front calipers to remove any trapped air.