Brake Warning Light Question

[farmtruckman]

On my 67 LB, I have the brake light on the lower dash left on. I just replaced the master cylinder and bled the whole system as I am installing a PB booster. Even though I have good pedal now, the light remains on. Any ideas?

[wt4speed#2]

Probably need to adjust the or center the valve in the proportioning block .

Tony B

[farmtruckman]

I'll check that out. I also now noticed that the brakes are dragging. Could I have the adjustment off on the shaft that goes from the booster to the pedal? I have shortened it all of the way but it is still a tight fit with the pedal in the resting position all of the way up to the limit.

[fordman]

if the shoes are dragging that would be a shoe adjustment problem

[farmtruckman]

Thanks for the response. They didn't drag before I put the booster on, so I assume it is the position of the shaft to the pedal that is applying brake in the resting position. Do you think if I back off the adjustment on the shoes, that will take care of things?

[fordman]

i assume the truck had manual brakes before this was done. maybe that could be part of the problem in the adjustment department.

[farmtruckman]

The pedals are the same, however, I bought the booster on ebay and I am assuming that it is the correct fit. I looked at teh LMC catalog and they have the same booster but there are three (3) part numbers, and the 67 of course only fits one part number so the shaft length on this booster might fit a 68-72 or pre-67. I just went out and jacked up the front end to see if the rims will turn and they do but there is a slight binding. It is reasonable enough to back off of the shoes a little bit on each rim enough to free them up. I will have to watch it if I ever put new shoes on since they are so much fatter. Now the trick is to get the brake switch working. The 67 is an odd year and has a unique stop light switch which I can't remember how it was mounted. When I mount it the way I think, it works until I tighten the bolt, then the brake lights stay on so I am forcing the switch on as I tighten. I need to see how another 67 works otherwise I either order a new one from LMC or rig up the newer configuration which is so much simpler. Snowing here so I am not getting much done. I also have a 72 SWB 4x4 parked next to the house that I had to move today and got it stuck in the snow/mud for a while. The 67 runs great and is closer to being done so I am concentrating on that one when the sun comes out (rare). Thanks for the advise and keep it coming. Maybe tommorow, I can back off each adjuster and allow it to be driven. The next trick is to figure where I am going to draw vacuum off of. The 352 doesn't have much to choose from. Only the kickdown fitting for the trans, so I am planning on teeing off of that.

[FLATBEDFORD]

I just replaced my master cylinder. The truck came with power brakes. After replacement of the master and bleeding the brakes, the warning lite is still on. The pedal is high and firm and the truck stops as good as my '96 f250. I'd like to know more about the proportioning block and adjusting it.

[FORDification]

Read the following thread:

http://fordification.com/forum/viewtopic.php?t=2214

As for the brakes dragging, since you say you just installed a new master cylinder, you should also check the pushrod between the booster and MC. It's part of the booster and normally this is an adjustable rod. If the rod is adjusted too far out, when you go to install and tighten up the MC, the rod is already beginning to push the MC piston. Not good.

[FLATBEDFORD]

So I bleed until the light goes off even if the pedal is high and firm? I did get goos streams from all bleed valves. A mechanic friend of mine says to hit the block with a hammer to re center the switch. Do these switches need cleaning or replacement? I also have to make sure the parking brake pedal isn't making the light go on.

[FORDification]

The e-brake has absolutely nothing to do with the warning light. It's just coincidence that the light is down by the e-brake.

Hitting the distribution block with a hammer is not going to center the valve. It's centered by a balance of front/back fluid pressure. They don't need cleaning (unless you had really dirty brake fluid). Just follow the instructions in the link above and you should have it corrected in no time.

[FLATBEDFORD]

I thought that the light would also indicate that the parking brake was set. This is my first Ford of this vintage. I'm learning....

[68F250]

What's funny is sometimes the parking brake can actuate the warning light if the valve is on the hairy edge.

[HugYourPlumber]

i bought my 69 about 3 months ago...the light above the e brake stays on constintly.The light has no lens on it. i always thought this was an ignition light until i read this topic...this truck has no power brakes.Can i get this light to go off?AND HOW??

[FORDification]

Yes you can....just follow the link in my reply 5 posts above this one, where I quoted the factory shop manual with instructions on how to center the valve in the distribution block.