a heads up on this issue on cars that dont recieve the brake flush/bleed service every 2 years
sediment builds up on the float and tower, the float can stick at the low position, a few taps with a screwderiver handle will free it up, if the sediment is bad enough just remove the roll pin and pull the tank to flush/shake it out so you dont pump the debris through the system.
unfortunatly at that mileage if its never been bleed/flushed regularly the master will probably start to bypass internally after its all done. so you probably should bite the bullet and get a new master to swap on. in most cases ive been able to bleed it out at the master fittings and keep air out of the abs/lines. crack em open, push the pedal down slowly to push the air out at the high point. do it slowly to keep from pushing air past the master fitting.
after a few shots, compress both front calipers with em cracked to make sure to push air out of the abs to the master.
most times i dont have to go to the calipers except to finish flushing
blunt nose chisel and hammer around the bleeder base/caliper scasting to pop the rust free to crack the bleeders
