Brake Failure Warning Light

I was parallel parked on the street last night while I ran into the post
office. As I pulled out of the parking spot, my "Brake Failure" light came on,
and stayed on the whole way home. The brakes seemed to work perfectly well.
This morning when I started the car to go to work, the light flashed briefly,
but then went off as soon as I touched the brakes and hasn't come on again.
I'm giving the car to my brother-in-law in a couple of weeks, and it would be
embarrassing if something major happened as he drove the car from my place in
Chicago to his home in Michigan. My car is regularly maintained, and my
mechanic hasn't mentioned the brakes needing any repair. Anyone know what this
is about? Should I be worried?

Thanks,
Patricia

 

The sensor is located on the left frame rail just below the bend. Pull thr
rubber boot back from the switch. If you see fluid the switch is bad.If not,
the proportioning valve just got off center causing the light to come on,
It's a common problem and nothing to be worried about.

 

Subject: Re: Brake Failure Warning Light

At the risk of being exposed for what I am (a know-nothing), where's the frame
rail, and the bend in what?

And thanks for the reassuring response.

Patricia

 

First, check the brake fluid reservoir. If level is fine go to #1. If
level is low then go to #2.

1. If the brakes work but the pedal keeps traveling after you stop
then it's probably your master cylinder.

2. Top up the fluid and monitor, driving at low speeds to test. If the
brakes work but the pedal travels further than normal but STOPS then
there is a leak in either a brake line or a caliper. For safety
reasons there are two brake lines running together, each one brakes
both front wheels and one rear (so if you lose one brake line you
still brake on 3 wheels). The braking to all four wheels is balanced
through this system by a Pressure Differential Valve which can also
fail and leak. A leaking brake line or calliper can pump out all of
its fluid in a matter of minutes but the PDV can leak slowly and let
air into the system.

And, of course, it could just be faulty wiring triggering the warning
light.

All of the above are brake problems I have had (replaced master
cylinder, calliper, and PDV) and I'm sure there are more suggestions
coming. You might try putting a large piece of cardboard or paper
under your car (or park on a nice clean driveway) and let it sit, then
idle it, pump the brakes, etc. and then move the car to see if you
have any leaks and where and what they are.

Good luck.
blurp

 

Follow the brakelines down from the master cylinder. The two lines go into a
brass block about the size of a pack of cigaretts. There four lines leaving
going to each wheel. They are split, left front right rear, right front left
rear. If any caliper or
line gets a leak, you still have brakes on both sides of the car to prevent
the car snapping around. It will still brake in a straight line. The switch
is on the bottom of the proportioning valve. Pull the rubber boot back and
check if it is wet. If it is the switch is leaking fluid.You can replace the
switch, but sometimes you have a problem bleeding the brakes so that the
switch comes back to center position so that the light will go out.

 

Subject: Re: Brake Failure Warning Light

While I appreciate your confidence in my mechanical abilities, I assure you
it's entirely misplaced. I'll tell my mechanic, though. Thanks!