sammyb

I just picked up a matching numbers '74 454 coupe tonight (don't ask why, because I don't need another Vette...it was local and it needs so little to be awesome...so I'll tinker, clean and polish then decide if I'll keep it.)

When I went to drive away, I lowered the handbrake and the dash brake light momentarily went off, then immediately came back on and wouldn't go off. The brake might have been dragging a little, but it was pouring rain and dark, so I couldn't much tell. (I was just happy the headlights and windshield wipers worked and the T-tops didn't leak a drop! :) )

The car also pulls to right under braking, but the brakes are relatively new, so I'll pound the calipers with a mallet to see if they're just a little stuck from sitting most of 2003.

Ideas on what I should look for first on the brake light?

Ben Taylor

There are only two things that would trigger the brake light on your dash.

The first is a switch underneath the E-brake handle, this makes the light go on based on the position of the handle, it doesn't tell you if the e-brake is accually doing anything.

The second is the sensor in the proportioning valve in the engine compartment. This senses the difference in pressure between the front and rear brakes, so if one of your calipers is malfuntioning this would be your indicator.

Since C3's use fixed calipers and not sliding calipers hitting them with a mallet would only put stress on the mounting bolts.

The first thing I would do is pop the lid off the master cylinder and check the quality of the fluid, then bleed the brakes.

1979toy

Step on the brakes hard a couple of times. That should center the proportioning valve if the system is working correctly. If not, look for leaks.

As mentioned above, the emergany brake handle switch can be on too.

sammyb

Ben,
Actually, I think you're probably right-on. When I took off the ebrake, I pushed onto the brake pedal, and that was when the light came on. My guess is that the proportioning valve is off. I wasn't sure if the brake light was both a ebrake and brake line pressure sensor.

Also couldn't remember exactly what the Vette calipers were like. I've done Porsche 911 brakes and TR-3 brakes since the '69's were done.

I'll check the fluid and bleed the brakes tomorrow.

jerryp58

Won't the brake light also come on if there's a problem with the master cylinder?

Smokehouse69

There is a pressure switch on the proportioning valve that has to be reset. Hard brake pedal pushes usually does it, if not try tapping it with a wrench a couple time. If the light still doesn't clear then check the calipers for leaks or air in one of them. The car probably could use a good brake flush, so purge and re=bleed the brakes.

Bobchad

Air in the rear lines caused by runout being out of spec.