Bleeding brakes - ABS 126
 

I replaced the front calipers and hoses tonight on my 300SDL. I did one caliper, and without bleeding it I had to drive the car in order to turn it around to get to the other wheel (working on the street). While doing this, I obviously had to hit the brakes. I proceeded to replace the other caliper, then bleed the front two calipers until there was a steady trickle of fluid with no air bubbles. The brakes feel great, but do I need to bleed the back calipers too? Did I get air in the whole system or just the front brakes?

By nature a bubble of air will work it's way to the high point of a system. I suppose a bubble could work it's way to the master cylinder and get pushed to one of the rear lines.

In practice I've yet to see air come out of the rear brakes when I only worked on the fronts.

I think you'll be fine, but why not take the opportunity to flush all the brake fluid?

Sixto

Bleeding brakes & brake fluid flush
 

The air generally does not travel between front and rear brakes, but as mentioned, it would be a good idea to make sure no air is the master cylinder. You could bleed the master cylinder by pressurizing the brake system, and then one at a time, open each brake line from the master cylinder. Make sure to place a rag under the master cylinder, and wash away any spilled brake fluid after you finish. Mercedes dealerships place importance on having a regular brake fluid flush performed, so if it has been a while or the condition of the brake fluid in the whole system is in doubt, I would suggest also doing a complete brake fluid change.

The best way is to use a brake pressure bleeder tool, that make it very easy for a DIY'er to do this. I use a product called Speedi-Bleed and love it, very fast, the quality is top notch, and decent price for what you get. You can find it at http://www.speedibleed.com