delliottg

Today I had two panic stops in a row in my 1976 300D (both behind someone who decided it's OK to stop on two lane highway when you're doing 60 mph on a blind bend). Anyway, the red brake light that generally indicates the parking brake is on came on steadily. I Googled and found where the brake light may mean two things (the story I found was for a 1984 300D, so it may not apply). The light can either be telling you that the parking brake is applied, or the brake fluid level in the master cylinder's reservoir is low. I checked, the fluid is right where it looks like it should be (top of the top line), and it's nice and clear, no burnt smell. There's a push button on top of the reservoir, so I thought that'd be how I reset the light, but pushing it does nothing. This is surprisingly hard to Google for, so I'm hoping someone here can help me.

Thanks!

David

tommd1977

David, the light is not "reset." The light is simply on and will remain on until the issue is resolved. As you said, there are two items to turn on the light. Parking brake and low brake fluid. The park brake must return far enough to turn the switch off, or of course the switch could be shorted. Also, there is a float in each part of the master cylinder reservoir. You said you checked the fluid level. At the reservoir, you will see two electric connections, one below each of the outer caps. Disconnect each and see which one if either turns off the light. If one of them does, remove the cap and the float assembly. You will probably find one has a problem, maybe the float came apart, or submerged. If removing both connectors does not turn off the light, check the park brake switch. Then maybe a wire shorted, but I think you will find a failed reservoir float.
Tom