Originally Posted by onehundred80

When I changed the brake fluid I wondered what special steps had to be taken with regard to the ABS and the Service Manual said none. I think that no oil sits trapped inside the unit, all the fluid is on the one side of the unit, the same side as the fluid in the lines. The pistons control the volume of system, if you get what I am saying. I can see you getting air in the unit, that is why the reservoir has to be kept topped up. The individual brake lines go to the ABS unit and are treated individually in it. There is no reservoir in that unit, just ins and outs and the pistons.