Hello all,
I have a 71 F100, 360, 4 speed with granny, power brakes, power steering.

Anyway, this week I did a brake job and replaced all 4 wheel cylinders, brake shoes on all 4 tires, and 2 brake hoses in the front.

The truck stops a lot better now and with no sticking or grabbing like it did before, but after I did it, the emergency brake light has come on and won't go off.

There is no sticking that indicates the emergency brakes are on after I have released it. When I depress emergency brake pedal it works the way it is supposed to...keeps the truck still, and when I release it the brake it seems to release fine no sticking or anything and the truck certainly acts like there is no e brake then.

So, my question is why is the emergency brake on all the time now?

Any help would greatly be appreciated.
andrew

 

Your proportioning valve needs to be recentered. This is accomplished by pressing on the brake pedal (not emergency brake pedal) at a stop, (with engine running if with power brakes) firmly and evenly until the light goes out. If the light won't go out after firmly pressing the brake pedal, then the brakes need to be re-bled or the proportioning valve replaced.

 

If you're talking about that little red light down on the lower left of the dash, it's not an emergency brake light. It's a warning light that advises you when either the front or rear pressure is low. Sometimes after you do a brake job you have to reset the brake distribution valve by "centering" it. It's under the cab on the driver's side. Just chase the brake lines until you run into a burfnagle with some wires sticking out of the top of it. That's it. I've never actually done it but they tell me you just crack either front or back line and have a helper sloooowwwwly push down the brake pedal until the light goes out. Some guys figure this is more trouble than it's worth and simply disconnect the warning light. Let us know how it goes.

Here's a photo of the light I'm talking about but I can't find one right now of the actual distribution valve/switch/whatchcallit.
jor

 

Here's what my Chilton manual says:

To centralize the pressure differential valve and turn off the warning light after the systems have been bled, follow the procedure below.

1. Turn the ignition switch to the ACC or ON position.

2. Check the fluid level in the master cylinder reservoirs and fill them to within 1/4 in. of the top with brake fluid, as necessary.

3. Depress the brake pedal and the piston should center itself causing the brake warning light to go out.

4. Turn the ignition switch to the OFF position.

5. Before driving the vehicle, check the operation of the brakes and be sure that a firm pedal is obtained.

It's pretty cool that yours actually works. It seems like I hardly ever see one of these trucks where the light hasn't burned out, or someone hasn't cut the wires to the bulb or switch.

 

I'll be interested in knowing if goracing's instructions actually work. I've read a lot of posts talking about what a pain it is to get the thing centered but it sounds as though all you need to do is hit the brake!
jor

 

Jor and Goracing, thanks a lot for the quick responses.

Jor, you are correct, it is indeed the same light that you took a picture of and posted here- thanks a lot. Now I know what it is and what it does.

I'm going now and try the advice that Jor and Goracing put up here for me...thanks Go-racing for looking it up in the chilton's guide and posting it. I'm stopping at the bookstore on the way home to get a Chilton's or order it if necessary.
I'll let you guys know how it turns out. This truck is still all original and has things working on it I didn't even know existed...
andrew

 

The only way I have gotten mine to go out is to bleed the brake lines. It appears that the switch is activated when there is a loss of fluid at one of the wheel cylinders. Here is the way I get the light to go out.
1. Turn on the ign so the light is on.
2. Have an assistant press and hold the brake pedal while watching the light.
3. Start at a front wheel cylinder and open the bleeder.
4. As the fluid starts out the bleeder the assistant should watch carefully for the light to go out as the pedal is going down to the floor. If the assistant sees the light go out then immediately close the bleeder valve. If it goes out but the comes back on, then you didn't stop the bleeder valve quick enough and now you need to move to a rear cylinder and try again.
5. If after 2-3 tries on the front without the light going out, move to a rear wheel cylinder and try again.
As fluid moves thru the lines it will cause the light to come on. If light were off and you open a rear wheel cyl to bleed it and enough fluid comes out the rear the light would come on then you would need to bleed a front wheel cyl and allow enough fluid to come out until the light goes off again but if you allow too much the light would go from on to off then back to on again which requires going back to a rear wheel and bleeding until you get the switch in the center again.
hth

 

I'm saving your instructions. Thanks, 8Nray.
jor

 

Hello All,

Well here's an update on my warning brake light problem.

I've basically tried all the suggestions that were given here and even followed the Chilton't manual procedure with NO change in the situation.
Here's what I did:

I rebled all the brakes...no change, light still on

I bled only the right front wheel and waited for the light to flicker or go out but it did not..no change

I went to the right rear wheel and rebled...no change

I found the brake proportioning valve itself and then opened the inflow line from the front line and had someone slowly push the brake pedal while brake fluid drained out all over me...no change.

I did the same with the rear brake line input..no change.

I haven't taken off the tires to check my work, ie- wheel cylinders, shoes, but I going to do it today just to be sure that everything is functioning properly. Could it be the pads are not adjusted properly?

Any other suggestions? The light was not on before I did the work on it so I am assuming that the brake proportioning valve is good, but am I wrong here?

Could the brake proportioning valve be bad or "stuck" There was a lot of rust in the master cylinder before I started bleeding it the first time and I wonder if some of it went into the valve somehow. I did not drain the cylinder...just figured that the bleeding would take out the rust.

ANY HELP would be greatly appreciated.
andrew