I’m replacing a leaking brake tube on a 1990 Chevy Celebrity. Since the master cylinder ran out of fluid, I’m bleeding the master cylinder as well as the affected wheels. The shop manual instructs me to bleed from the forward (blind end) and rear (cowel) master cylinder connections but there are no references or illustrations showing what these terms mean. So, of the 4 connections to the master cylinder, which do “blind end” and “cowel”
refer to?
Bleed all four. The blind end faces the front of the car. It’s called blind because there’s no openings on the front of the master cylinder. The rear end faces the driver. The cowel is wheat the bottom of the windshield attaches to.
Since the m/c when dry you may need to remove the m/c and bench bleed it.
How did the master cylinder run out of fluid? Do you just mean the fluid level went all the way down as a result of a ruptured hose or wheel cylinder or something? Every time this has happened to me, I’ve always just bled at the wheels and it’s been fine. I think they design the brake systems so it’s very difficult for air to actually get into the master cylinder-- the only time I’ve ever had to bleed one is when I’m installing a new one.
The fluid went down to the top (or below, can’t really tell) of the valve orifice visible from the filler cap opening. It was caused by the rupture of the left rear wheel brake pipe. The shop manual tells you to to bleed the mc from two fittings, the front blind end and the rear cowel end when this happens and, ofcourse, the affected wheel.