My 1990 240 was leaking brake fluid between the booster and the master cylinder, and braking power was all but toast. Before replacing the Master Cylinder, I noticed that the engine would stutter when I tried to brake. I'd been having some issues with the engine dying when I'd put it in gear before with the computer telling me I had lambada issues- now I'm wondering if it is the the braking.

There was some crud beteen the Cylinder and the Booster where they fit, but I cleaned it out and the seal looks good. Is my booster diaphram leaking, causing a bad vacuum when I brake? Or is there perhaps a sensor in the 1990 240DL cutting the engine after detecting pressure loss in the brake lines?

[Edit: There is no code for the reccent stalls]

 

there's no sensor like you describe.

most likely, any engine stuttering as you describe is a vacuum leak. hard to say where.

 

Start the car and have someone press the brake pedal while you listen to the brake booster. You may be able to hear a hissing sound coming from the booster if the booster is leaking and yes a leaking booster would cause the problem you are having, it is a big vacuum leak.

 

brake booster check valve...

2 dollars at junk yard or new for 8 bucks...

white plastic plug that goes on the booster...it has a hose attached and goes to the intake manifold....
use your fingers to take out and if you can't take out the hose attached to it...just slice it up a little and cut the sliced bit off when re attaching it to the new/old valve

then grab the plastic valVe and blow on both openings....IT IS BAD IF YOU CAN BLOW through BOTH DIRECTIONS...GOOD IF IT BLOWS ONLY ONE DIRECTION WITH NO AIR BYPASSING AT ALL ON OTHER SIDE...IF YOU CAN ONLY BLOW ONE DIRECTION AND NONE THE OTHER, THEN IT IS GOOD BUT IF IT BLOWS BY EVEN A LITTLE, IT IS BAD.

see image of valve