Problem Bleeding Brakes w124 1992
 

Started the day with the idea that I should do a simple brake fluid change before the weather turned to chilly, if it ever does this year. Anyway, the plan was to pull about 80mL of fluid through the passenger rear bleed valve with a mity vac hook-up. About 40 mL came through then bubbles then just air. The volume in the reservoir didn't decrease any visually. Tried for at least 30 minutes and just got air with no change in the reservoir. Then tried the driver rear and had the same thing happen. However, if I bleed the front calipers fluid come through and the reservoir goes down.

What did I do wrong and how can I fix it?

My '92 has a 2nd reservoir behind the main one. They are separated by a plastic inner wall. You have to ensure the brake fluid level is very high to allow it to fill the 2nd reservoir. I believe this is the rear brakes and can bleed dry if you aren't careful.

-John

Ya wants to be pushin not pullin that brake fluid....

Buy or make a power bleeder out of a pump sprayer.

I just did it last weekend, with a power bleeder, works a treat.

Had similar issues w/my 300D. Check this thread for some ideas Need help w/W124 brakes :( - Benzworld.org - Mercedes-Benz Discussion Forum