edit: all fixed


My reservoir is so grungy I didnt know it had two parts! And that you have to overfill the rear part to fill the front section. Read a few dozen threads and a few diy guides before coming across that fact.

[stupidity below]

While I thought I'd checked the brake fluid level less than a thousand miles ago, I was very surprised the other day when the pedal was extremely soft right as I pulled out of the drive way. At first the old stain line on the reservoir fooled me but then I checked the level by opening the cap and it was empty.

So I started the brake fluid changing process with a hand-held Mityvac at the rear wheels and a quart of DOT 4 fluid. I was able to pull about 6-10 ounces of fluid (cant remember exactly) out but it no more came out. Even after greasing the threads on the 9mm nipples (which have alot of play) and replacing the flexible hoses at both rear wheels, I can't seem to pull new liquid through, only lots of air. I can hear it gurgling somewhere in the hard lines when I pump up the Mityvac before opening the valve. The reservoir level mightve changed after those first ounces were pulled but I can't get any more to come through, only bubbles.

The pedal continues to go straight to the floor and no amount of pedal-pumping changes the reservoir level. Even if one of the back 9mm nipples is cracked open. Shouldn't it push something into those lines?

I would assume the hard brake fluid lines are the next suspect, but I can't tell where it goes much after the rear T connection to inspect it visually. I suppose I could disconnect it up there to use the Mityvac and see if that isolates the issue past the split, even though I don't see any visual evidence of a leak.

Could it be something to do with the master cylinder? No visual evidence of leaks up there either.

I'm about to throw in the towel and let a good local mb mechanic to look at this.