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

sbr,

It would seem the brake fluid is running out somewhere. In my 1982 240D this happened and it took me a few days to figure out it was the hydraulic cylinder at the brake pedal (edit: that was the clutch pedal and you have an automatic, so you do not have a clutch pedal - sorry). The fluid did not leak on the street or driveway, it leaked on the floor. I ended up flushing the floor area with water to clean the stuff out, but it ruined the bottom of the rug (the molded/contoured stuff that fits around the ducts and wireways that go under the rug) and was a huge pain to replace. I am over six feet tall and just did not fit very well under the dashboard. Good Luck and I hope this helps. Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

Thanks Jim. I noticed what appears to be brake fluid on the inside of BOTH rear tires. So I'm thinking it might be the wheel cylinders? I just want to be sure I can drive the 20 miles to the dealer on monday without total brake failure. I would be able to use the parking brake to help stop me correct???? Anyone?

sbr
'79 450SL
76,000 miles

sbr,

The parking brake has no hydraulic circuit and therefore has not enough mechanical advantage or leverage to be an effective brake while you are moving. It is also a drum brake and not designed to act as a dynamic brake - you will notice if you drive with the brake on for long it needs to be adjusted to take the shoe wear into account.

Bottom line is the emergency brake cannot be counted on to get you to the dealer.

Sounds to me like the hoses are weeping that go to the calipers, or the calipers are really shot. Replacing either of these is pretty straightforward. Good luck, Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

Remove the rear tires and check calipers for leaks. If there is a hint of a brake fluid leaking, the calipers are bad.

They are not too hard to rebuild yourself (I did mine). If you are not comfortable with rebuilding them yourself, replacement with new calipers is a simple do it yourself job. Of course you have to bleed the rebuilt or new calipers. Some will bleed by gravity and others need the brake pedal depressed. This takes a second person.

If the brake pads are more than 1/2 worn out, you might as well replace them. Also check the hoses for leaks and replace them if any leaks are present.

P E H