I re-read what I said last night and what I said about "don't believe........... Well I meant this if the bleeder isn't the highest point. Example: There are some GM trucks with dual wheel cylinders placed in a horizontal orientation. It is impossible to bleed the air out of either cylinder in that position. Similar as mentioned here. The backing plate had to be unbolted and rotated 90 deg to bleed them properly. The "flat-rate" method was to insert a piece of .002" feeler gauge down past the wheel cylinder cup creating a leak to allow total bleeding and remove it when finished.........Bruce