First posting - please bear with me - i'm freaking here...

A 1987 300D, antilock braking, soft brake pedal, spongy - felt like bubbles. Figured to try to purge (edited out:bleed) the system (seemed the first thing to try - fluid a little low). Looked at all brakes yesterday - no leaks/wetness anywhere.

Today: suctioned-out the old fluid from the reservoir, looked a bit dark, filled it with new DOT4. Pedal felt a little better with the engine running.

Hooked a Mityvac to the left front caliper to start purging the lines, pulled about 10" of vacuum, cracked the valve and withdrew a bit of fluid with several bubbles in it. Did it twice more - more fluid & some bubbles. Maybe pulled out just under 2oz. of fluid total. THEN realized it could be leaking air around the threads.

Got someone to help me to play 'pump & hold the pedal, burp the valve". NOW the pedal goes all the way to the floor, hardly any fluid coming out of the tube (what comes out doesn't look as clear as the new I put in) and have tried it 15-20 times with NO improvement.

When the pedal is pumped and held I can still spin the rotor. Haven't checked the other wheels or moved the vehicle yet - left front is still jacked & wheel-off.

HELP! PLEASE tell me I didn't screw-up the ABS! And what can I do to fix this? This is my first car w/ABS (other cars are '83 MB 240D and '86 VW Jetta - both power & assist but no ABS) and vacuum or 'pump/burp' bleedings have always worked fine on them.

(desperate) Thanks!