380 SEC Brake trouble

[Crausch]

Hello All.

I just purchased my first Mercedes. A 1983 380 SEC. I love this car. It has some issues as you would expect from a car 26 years old. Love it none the less. I have a question about the brakes I hope someone can help me with.

I needed to replace the front right caliper. I did so. Pads are fine and the job was straight forward. I bled the brakes. Front left, rear left, rear right and finally front right. I had a nice solid pedal feel when finished. When I started the car to take it for a test ride the pedal went almost to the floor. I shut it off and double checked for leaks and fluid level in the master cylinder. No leaks and master cylinder just below max line. No leaks around the master cylinder or the brake servo (booster). What am I missing? Does this point to a problem with the brake servo? If so are they repairable? Any leads on getting one used?

Thanks for any ideas or assistance.

Christian