Brake imbalance switch diagram
(click to get a bigger picture)
Early Bronco's without disk brakes did not have a proportioning valve,
had a brake imbalance switch. If the pressure was not equal in the front and
rear brake systems, the plunger would go off center and trigger the light on
the dashboard. This is to let you know if there is a failure in your brake system.
To get the light to go out, you must recenter the plunger. The
easiest way is
to bleed either the front or the rear brakes. Start by bleeding one of the
front wheel cylinders. While you are bleeding it, have someone in the truck
watch the brake light and let you know when it goes out. If it never goes
out, or it goes out then back on (you passed it), you need to repeat the
procedure, bleeding one of the rear cylinders. The light will go out once
the plunger in the switch is centered.
The Official version:
|Centralizing the Pressure
After any repair or bleeding
of the primary (front brake) or secondary (rear brake) system, the dual-brake
system warning light will usually remain illuminated due to the pressure
differential valve remaining in the off-center position.
Page by Marc Reiter - last modified 11/24/99
©2002 copyright BroncOhio Early Bronco Club.