After storing my '79 450SL for 5 months I ran it last Saturday. It started like it had been sitting overnight. Backed it out of the garage and noticed that the brake peddle went to the floor. Hmmmm, this happened last year, brake peddle did not go to the floor, but I had to add about half a container of DOT 4. So after I filled the fluid resovoir, and pumped the peddle, nothing, peddle went to the floor. I do have some brakes, (peddle at the floor), it's enough to slow you down and stop at about 30 mph. I made an appointment with the Dealer for Mon. 4/8, and I'll drive it (20 miles). Any ideas what he problem might be? Had the brake fluid flushed last spring and had a new master cylinder (leaking) installed at the same time. Ran fine all last year. What could have happened from sitting over the winter? Thanks.

sbr
'79 450SL
76,000 miles