F-And P-100 Series Brake Systems Contents; Description And Operation; Hydraulic Self-Adjusting Brake System; Self Adjusting Brake Assemblies - Ford 1964 F-100 Shop Manual

2 - 8
PART
2-2
F- AND P-100 SERIES BRAKE SYSTEMS
Section
1 Description and Operation
2 In-Truck Adjustments and Repairs 2-9
Page
7-8
Section Page
3 Removal and Installation 2-9
4 Major Repair Operations 2-14
DESCRIPTION AND OPERATION
HYDRAULIC SELF-ADJUSTING
BRAKE SYSTEM
Single-anchor, internal-expanding,
and self-adjusting hydraulic brakes
are used on F- and P-100 trucks.
A n independent manually-oper-
ated parking brake operates the rear
wheel brake shoes through a m e -
chanical cable linkage.
T h e self-adjusting brake mecha-
nism consists of a cable, cable guide,
adjusting lever, and adjuster spring
(Fig. 1). T h e cable is hooked over
the anchor pin at the top and is con-
nected to the lever at the bottom.
The cable i s connected to the sec-
ondary brake shoe by means of the
cable guide. T h e adjuster spring i s
hooked to the primary brake shoe
and to the lever.
The automatic adjuster operates
only while the truck is moving rear-
ward and the brake pedal pressure is
firmly applied.
With the truck moving rearward
and the brakes applied, the "wrap-
around" action of the shoes follow-
ing the drum forces the upper end
of the primary shoe against the an-
chor pin. T h e action of the wheel
cylinder moves the upper end of the
secondary shoe away from the an-
chor pin. T h e movement of the sec-
ondary shoe causes the cable to
pull the adjusting lever upward and
against the end of a tooth on the
adjusting screw star-wheel. T h e up-
ward travel of the lever increases as
lining wear increases. W h e n the lever
can m o v e upward far enough i t
passes over the end of the tooth
and engages the tooth. W h e n the
brakes are released, the adjuster
spring pulls the lever downward
causing the star-wheel to turn and
expand the shoes. T h e star-wheel is
turned 1 tooth at a time as the lin-
ings progressively wear.
With the truck moving forward
and the brakes applied, the second-
ary shoe is against the anchor pin
and the primary shoe is moved
toward the drum. Therefore, the ad-
juster does not operate.
The rear brake assembly is basi-
cally the same as the front brake.
The conventional parking brake lev-
er, link, and spring are used in the
rear brake.
The anchor pins on all brakes are
fixed and non-adjustable.
ANCHOR PIN PLATE
ANCHOR PIN-.
FORWARD
PARKING BRAKE LINK
LINK SPRING
ANCHOR PIN PLATE
ANCHOR PIN
CABLE
ANCHOR FITTING
PRIMARY
SHOE-TO-ANCHOR SPRING
PARKING BRAKE LEVER
RETAINING CLIP
SECONDARY SHOE-TO-
ANCHOR SPRING
FORWARD
SECONDARY
SHOE
SHOE
HOLD-DOWN
SPRINGS
AUTOMATIC
ADJUSTER SPRING
PARKING BRAKE CABLE
HOUSING RETAINER
V PARKING BRAKE LEVER
PIVOT HOOK
REAR BRAKE PARKING BRAKE
CABLE AND
HOUSING
AUTOMATIC
ADJUSTER SPRING
FRONT BRAKE
PIVOT NUT
CABLE
SECONDARY
SHOE
CABLE HOOK
ADJUSTING LEVER
SOCKET
ADJUSTING SCREW
H1339-A
FIG. 1 —Self Adjusting Brake Assemblies