I need some advice. I began installing Speed Bleeders on my `81 300SD as I was changing my brake fluid (ugly dark tea color). I started on the right rear wheel, furtherest from the master cylinder. I quickly swapped the old bleeder with the new one and began pumping. At first I got ~ 1/2 pint of fluid, then the fluid stopped coming out. The reservoir was over half full, so it wasn't sucking air.

Lots and lots of pedal pumping only produced air at the bleeder valve. Stumped, I pulled the Speed valve out and put the old one back in and cracked it open a half turn. Copious pumping only produced some air in my catch bag. I then put a hand vacuum pump on the valve and pumped away- only air came out. I pulled the valve and put a bit of teflon tape in case the threads were allowing air in. Still no good. Started the car and tried again, same thing. Now I have zero brakes and the brake light on the dashboard is on. What have I done? Everything worked great until I tried to bleed my brakes, and I'm totally at a stand still.

Dave

The reservoir has two chambers and they don't fill or empty at the same rate. Maybe the rear chamber is empty and you're seeing the front chamber full.

Sixto
95 S420
87 300SDL

Fill past the full line all the way to the neck. Slowly the fluid level will start to drop, meaning the rear chamber is filling. Use your shop light to watch. Once you know what to look for it's easy to tell when it is full again. Use of a presure bleeder usually prevents this from happening and speeds things up.

When I get home from work, I'll verify the contention that the reservoir must be filled to the neck. Also- it makes perfect sense. You guys are very appreciated.

Dave

Yeah, the reservoir has two chambers - one for the front brakes, one for the back brakes. The front brakes get the front 90% of the reservoir, so it's tough to see whether there's any fluid in the back portion. Hold your shop light right up to it.

The other guys are correct, you need to fill it all the way up to the neck to insure the rear portion gets fluid. I think you can empty the rear with about ten vigorous pedal pumps.

Don't ask how I learned all this

- JimY

That's just grand. I have brakes now, yay. But I'm irritated at the time I wasted. It's obtuse that the reservoir will appear to be at the correct level but still suck air. I consider this knowledge to be hard won. And I really appreciate the advice folks.
-Dave