Weird W126 Brake Problem
 

Picked up a 380SEL with my son yesterday and besides the little niggling problems (e.g., wiper blades, paint, snafu window lifts), the brake pedal was almost to the floor before it was able to stop the car. The brake reservoir was pretty much empty. Added fluid and tried to bleed the brakes but couldn't seem to be able to get fluid out the back brakes.

Put in a new master cylinder, bled the brakes and got nice clean fluid out of all four corners now. Verified all four corners had great pad thickness and nothing appeared too hot, like a stuck caliper

But the brake pedal still goes too low. It's better but no where near my 560SEL pedal.

Now what???

How do the rubber flex lines that go to the calipers look? They older?

Brake lines?? Stalling?
 

I know those lines are older. I didn't look at them for swelling/ballooning (yet). Good idea!! I'll see what I can see this afternoon when the car comes back.

New problem - it wants to stall when you stop. I haven't had a chance to see if the idle is too low, but what else is a common reason for the stalling?

Thanks,
Mike

OK, the brakes feel fine most of the time but it's losing brake fluid. Had to refill the reservoir in one day.

With the engine off, the brakes are nice and hard. With the engine running, the pedal will slowly go to the floor.

It's a new master cylinder so it shouldn't be into the vacuum booster. Looked at all the rubber lines to the calipers and they don't have any signs of fluid leak nor do they balloon when the pedal is depressed. No fluid on any caliper or rotor. No signs of brake fluid under the car, but it leaks tranny fluid and engine oil so it could be masking the brake fluid.

Suggestions where this leak could originate?