[XR7Cougar]

The brake pedal went ot the floor last week in my 1970 Bronco - it has 4 wheel drum brakes with no power booster. The interior brake warning light did NOT go on.

No fluid was leaking from the wheel cylinders so I assumed a bad master cylinder. I swapped that out and as I was bleeding the brakes a rear wheel cylinder blew out - I'm suspicious this was the problem to begin with. So I replaced both rear wheel cylinders too.

Now the brakes work but my interior brake warning light is now ON?! I have rebled the master cylinder and brake lines twice now and the brake light will not go off. The truck stops OK but I havent gotton on the brakes very hard yet.

Any ideas why the brake light won't go off? Where do you think I should go from here? (trying to avoid a trip to a "real" mechanic)

 

[mikemustang289]

Mines been on in my car since I bought it 5 years ago. It's never bothered me enough to find out why. I think it may be have to do with the emergency brakes although as far as I know there is no switch on the emergency brakes, just a lever with a cable. If your bakes work then I wouldn't worry about it.

 

[mustangboy]

Try hitting the brakes hard with one of the front brakes lines open.You need to recenter the little piston inside the switch which has moved to the rear since it lost pressure there when you were bleeding the rears.It doesn't have anything to do with the emergency brake.

 

[71hotrodpinto]

Yup , what i was gonna say
recenter the switch.

 

[FEandGoingBroke]

Anything over 400ft lbs on the pedal with the line open or closed and it should re center the switch...

 

[71hotrodpinto]

I wouldnt think so, the switch is between the two circuits. when the front brakes fail the plunger pushes forward to close off the front circuit. Vice versa on the rears.
Now his is stuck at the rear because of his rear wheel cyl failing. If you just close up both circuits again, how is the plunger going to move?
Im pretty sure you need to either bleed the fronts again with the pedal pressure OR (more involved but a better solution) take the valve off and apart and recenter it manualy. That way you get to clean and bleed the whole system anyways and youll know its right.
Just my opinoin
Good luck


_________________
71 Pinto,5.0 Roller block,B303,1.7 Rockers,Crane beehives'68 302 portednpolished heads. Cut n re-welded,coated Must II headers,Rpm Airgap,Holley 570,Msd dist steel gear,Crane HI6
"The MONEY PIT"

<font size=-1>[ This Message was edited by: 71hotrodpinto on 3/20/06 2:37am ]</font>

 

[dacofa]

Actually some of the old ones you just hold the pedal down hard for about 15 seconds and it recenters itself. But each make is different. Just go get a book on it and be done with it. It'll come in handy soon enough. Wait till you work on the Ujoints and diffs. LMAO

 

[Blue Fastback]

Jam on the pedal hard. The equalized pressure will recenter the shuttle valve and turn the light off.

 

[67Coug]

Don't just mash on the brake pedal. Have as assistant crack open a front bleeder screw slightly. With ignition switch on SLOWLY push the pedal down until the light goes out. Hold the pedal right there and have your assistant close the bleeder screw. Early switches were not self-centering. If you press the pedal too far the light will come on again and you will have to then do the same to the rear system. Just play with it until the light stays off.