The brake light just started coming on in my '76 El Camino. It is not loosing fluid and it stops fine. Ideas? I'm going to replace the front pads this week; I replaced rear pads last months when I replaced a leaking rear seal. Could this be a problem with the master cylinder? I don't know if it is the original or not. How does the brake light work...off pressure loss, pedal travel?

There can be multiple sensors tied to the brake indicator light. For example in my 3rd gen both emergency brake on and combination valve/switch can turn on this light. You might need to *temporarily* disconnect sensors until you id the one in question.

I would note that you do not have to lose all braking or brake pressure for the light to come on. The brake system actually has two seperate circuits and if one has less pressure than the other the light comes on.

Based on your observation that you are not losing fluid, I would suspect the master cylinder is at fault. You may be able to get new seals in a rebuild kit and fix it that way if the bore is not rusted. Or just replace the master cylinder.

i know on my 5th gen when I get in the car I will lightly press on the
e-brake and the dash light will come on