Brake light goes on when driving?

[Fiat88]

The brake pedal on my car doesn't have the greatest feel to it(a little spongy) ever since I redid my rubber brake hoses and rebuilt calipers a year ago. Don't think I got all the air out but the car stops ok just not on a dime. I noticed while driving the brake warning light goes on sometimes. Gonna have the mechanic bleed them when I bring it down for the alignment. So, the brake fluid level in the reservoir must be dropping a vast amount for the light to come on, right?

[narfire]

Have you checked the fluid resevoir? still have juice in there?
Get down and have a look at the pedals. I believe the brake has a contact switch up in the hard to reach place. Perhaps that is acting up or a loose conection there.

[opus10583]

Hi,

Mine is now the second Spider I've had that required jiggling of the handbrake lever to trigger the handbrake release switch.

HTH,
Mark

[opus10583]

My car fixed itself tonight: The plunger for the parking brake light switch achieved its dream of freedom.

[124JOE]

The brake pedal on my car doesn't have the greatest feel to it(a little spongy) ever since I redid my rubber brake hoses and rebuilt calipers a year ago. Don't think I got all the air out but the car stops ok just not on a dime. I noticed while driving the brake warning light goes on sometimes. Gonna have the mechanic bleed them when I bring it down for the alignment. So, the brake fluid level in the reservoir must be dropping a vast amount for the light to come on, right?

take the front wheels off and put a c clamp in the caliper pushing the air bubble back up into the reservoir
put wheels back on then do the back just remember they screw in so no c clamp

that will bleed it out

[manoa matt]

" So, the brake fluid level in the reservoir must be dropping a vast amount for the light to come on, right?"

Given what you describe, that is the most likely scenario. Also check the electrical switch under the parking brake handle.



"take the front wheels off and put a c clamp in the caliper pushing the air bubble back up into the reservoir
put wheels back on then do the back just remember they screw in so no c clamp that will bleed it out"

No, it will not, it will push the air bubble back into the hard line as there is not enough piston travel to force enough fluid back into the reservoir. Just crack the bleed screws and push the pedal down slowly.

[124JOE]

that will let air in the line when you let your foot up unless you have someone to help

ps. you can gravity bleed it,just open and let the fluid drain untill the bubbles stop and it runs all fluid then tighten

[minimike]

easy enough to bleed with a second person to pump the pedal and hold it down. If you don't know how to bleed the brakes,
read this:

NOTE: DON'T GET THE BRAKE FLUID ON YOUR PAINT. IT WILL STRIP THE PAINT OFF YOUR CAR!!!!!

Start at the wheel furthest from the brake M/C. so it's passenger rear, drivers rear, passenger front, then drivers front.

You'll need a glass jelly jar, clear plastic tubing that fits bleed nipple. On fiat, I believe rear and front bleed nipples might be different sizes. Check and buy appropriate sized hose. you only need 12" of hose.

open end wrench sized to fit the bleed nipples. Again, I think they might be different on front and rear.

helper to pump the brake pedal, male or female, with a right foot.

a couple of small bottles of brake fluid, usually DOT 3, unless you know you're using synthetic.

floor jack, 4 jack stands.

brains

eye protection

paper towels

throw away medical gloves

newspaper. (I like to put some news paper under the caliper to keep brake fluid from spilling on the ground)


Top up the MC (master cylinder) with fluid, jack up car on 4 jack stands. remove tires, make sure you can loosen all bleed nipples on calipers. Proceed as follows for each wheel. helper pumps brake pedal 10 x and holds pedal down. He yells "down" and hold pedal to floor. You open bleed nipple. You should have a clear plastic hose, like from a fish tank filter pump, and a clear glass jar to catch fluid. The idea is that you put some fluid in the jar, keep the hose below the level of fluid so caliper can suck air back into system. Other side of hose goes on bleed nipple. Hold jar with fluid and hose end below fluid. When helper has pressurized system and is hold pedal down, you open the bleed nipple and watch the fluid travel into the jar. you might need to do each caliper 4+ times until you see clean fluid enter the jar, and watch for no air bubbles in the hose. When you have no air bubbles, that wheel is done. Proceed to the next wheel.

REcap: helper pumps pedal and yells down holding pedal down. Each time you bleed and lock up bleed nipple, you yell: Pump it up. He does 10 pumps and yells down and holds pedal down until you tell him/her to pump it up again. When you get finished bleeding the last caliper, pedal should be up and pressure should be firm. If not, re bleed. If this doesn't solve your problem, a leaking master cylinder internally might be the cause.
mike