OK, this is my first ever question in the forums...

I have a 76 F250 4x4, 4 speed, dana 44 and 60, divorced transfer case and what should have been a 360 is now a 410.

As a side note the Frame and Drivetrain are a 76 Cab and chassis, mated with a 73 body, so I am not positive if the master cylinder and power brake assembly are from a 73 or a 76

Heres my issue:

The idiot light on the dash is staying on.

I have flushed fresh brake fluid through all the lines, longest line first.

I have searched the forums regarding proportioning valves with no successful resolution.

I have looked at the pictures of the proportioning valves and mine has 5 lines, 2 from the Master Cylinder, 2 for the front discs and one to the rear drums.
It does not have the plunger that I can pull on.

I have filled the Master cylinder to within a 1/4' of the top, with brake fluid and depressed the brake pedal, light stays on.

I have disconnected the with at the valve, light goes out, I assume the wiring is not shorting out.

I have lifted all 4 wheels and had my wife depress the brake so I can assure the brakes engage, and the release, they all do.

I have also loosened the brake lines near the proportioning valve to try and release pressure, light stays on.

So, any suggestions from the masses?????
Also were my explanations clear enough?
Cheers
Darren

 

First, how are your brakes? If they're okay (and you're sure), try the following:
Crack the bleeder valve on one of the front brakes and SLOWLY depress the brake pedal. Watch the light to see if it goes out. If it does, stop, close the bleeder and hit the brakes to see if it will stay off.
If the light stays on, repeat the process on a rear wheel.
If the light doesn't go out at all it could be a bad proportioning valve (the little spool that triggers the light switch is frozen) or the switch is bad. The switch is still available.
If the light goes out but comes back on, the light could be doing it's job and telling you there's something wrong with your brake system.

 

Heres the outcome........
I pulled the proportioning valve, showed it to another dentside guy, it was the wrong valve, I had a proportioning valve from a 75 or older (w/o disc brakes)
He had a parts truck I pulled the proper one from.
I ordered a new switch from Ford, all is well now.
Mike, thanx for the help
Cheers
Darren