Betty's Nova lights up

Dear Car Talk

Dear Car Talk | Feb 01, 1991

Dear Tom and Ray:

I have a 1987 Chevrolet Nova. For over a month now I've noticed that the "Emergency Brake" light on the dash stays on for the first fifteen minutes of driving every morning. It seems to be taking longer and longer now to go off. I tried the emergency brake, and it seems to be OK. What could it be?

TOM: Good question, Betty. The "Emergency Brake" or "Brake Warning Light" has two functions on most cars. One is obvious (even to my brother); it tells you when the parking brake is not completely disengaged.

RAY: But that light also tells you when the brake fluid level is low. In your case, the level is right on the hairy edge. In the morning, when it's cold, the brake fluid shrinks (things shrink when they get cold...if you don't believe me, reach into your husbands swim trunks next time he goes for a dip in the ocean). After you've driven a while and things have warmed up, the brake fluid expands, crosses the "minimum" line, and the "Brake" light goes out.

TOM: So, your next question is probably WHY is your brake fluid low? Another good question, Betty! There are two possible reasons. One is that your brake pad linings are worn out. When they get thin, the brake fluid fills up the space once taken up by the linings. When the pads wear down enough, the light goes on to warn you.

RAY: The other reason the brake fluid could be low is that you have a leak in the system. In either case, you should take the car in immediately and have the brakes thoroughly checked. It's probably just pads, but you never know.

TOM: You might also think about re-acquainting yourself with your owner's manual, which explains all of this. It's probably still in the glove compartment. Try looking for it under all those unpaid parking tickets.

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