Hello,

My name is John and I am new to the forum. I work in construction in Seattle. I will get right to the point.

The emergency brake light will not go off in my truck. I have checked the cable and it is working well no kinks or loose fittings. Tracked the wires to the harness and nothing loose there either.

Has anyone else had this problem?

Thanks in advance for any help.

 

which Brake light are you referring to? If it's the one on the lower left dash, then it is probably the switch in the proportioning valve / Distribution block. It should be located on the inside frame rail near the front Cab mount. They tend to stick and cause the light to remain on. There are several thread about this issue you can find with the search feature.

 

The light come on when there's a failure in your brake system.

You can remove the switch plug on the distribution block.

The Distribution block loads up with crap over the yrs and the inner trick rod slides one way and most of the time gets stuck in place when trying to reset it.

These Distribution Blocks need to be cleaned and or rebuilt if you can find any parts.
Or replaced.
orich

 

Thanks for the help fellas, I will check it out in the morning. I tried the search function, but had no luck. Probably using it the wrong way. Anyway thanks again.

 

as a last ditch effort, crack both fittings on your master cylinder a little then retighten.
this trick will sometimes balance out the distribution block.

 

I see this component called the wrong thing quite a bit. For 67-69 it is a Distribution Block with a Differential Pressure Switch. Starting in 70 on passenger cars with disc brakes it is a combination valve which performs the the same duty as it's predecessor but also includes the Proportioning Valve in line with the rear brakes. If there is a pressure differential (one side is low possibly because a leak) then the internal shuttle moves towards that side and activates the switch. First check your wheel cylinders and lines for a leak. If no leak, then bleed the front and see it the light goes out. If that does not work, try bleeding the rear. If that does not work then the shuttle is probably stuck and the block will need to be removed and rebuilt. Notice how I did not call it a valve. The rebuild parts are four X-rings (most people just use O-rings) and a copper washer.

 

This is not an emergency aka park brake warning light, it's the low brake fluid warning light.

The plastic switch that operates this light threads into the Brake Pressure Differential Valve (correct FoMoCo terminology).

C7AZ-2B264-A .. Low Brake Fluid Warning Light Switch / Obsolete

Applications: 1967 (only) all FoMoCo vehicles.

This switch (and the 1968/79 version: C8AZ-2B264-A) are turds, notorious for failing!

 

Here is a source for the parts you'll need to repair the BPDV.

https://www.musclecarresearch.com/valve-kit-whead1