'70 K-10 Parking Brake Light Stays On
 

My parking brake light is constantly on. Fluid is full. Any ideas?

Re: '70 K-10 Parking Brake Light Stays On
 

these trucks do not have a parking brake light// the brake light signals that you have a brake problem

Re: '70 K-10 Parking Brake Light Stays On
 

Fluids good. Brakes are new within about 5000 miles.
What type of problem causes the light to come on?

Re: '70 K-10 Parking Brake Light Stays On
 

Your proportioning valve needs to be reset. Push the button in on the front. It's under the black cap.

Re: '70 K-10 Parking Brake Light Stays On
 

There is no button or black cap on my proportioning valve. It's solid with the only connections being fluid lines to the master cylinder and the brakes.
However, while looking for the button you describe, I noticed that the sensor wire was pinched between the master cylinder and the firewall. I loosened it up, got the wire out, and, Voila! Brake light is out!
Thanks to all for your help!

Re: '70 K-10 Parking Brake Light Stays On
 

Some don't have a reset button!
But now the thought is---Do you have a prop valve or a distribution block?
Are you still drums all around or disc/drum?

Re: '70 K-10 Parking Brake Light Stays On
 

All drums.