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2-16
2-3
F-250 AND F-350, AND P-SERIES
BRAKE SYSTEMS
Section
Page
1 Description and Operation
2-16
2 In-Truck Adjustments and Repairs
2-16
Section
3 Removal and Installation
2-18
4 Major Repair Operations
2-25
DESCRIPTION AND OPERATION
Hydraulically-operated service
brakes are standard equipment on
F-250 and F-350 and P-Series Ford
trucks.
The standard hydraulic brake sys-
tem on some trucks i s assisted by
either a frame or dash-mounted vac-
u u m booster which m a y be installed
as optional equipment.
P A K K D N ©
S R ^ K E S
The type of parking brake used
in the truck depends upon the par-
ticular truck model and the trans-
mission type.
F-250 Series trucks with a 3-speed
light or medium duty transmission
have cable actuated parking brakes
in the rear wheel brake assembly.
The F-350 and P-Series trucks are
equipped with a transmission mount-
ed (external contracting band) park-
ing brake.
The band type parking brake con-
sists of a brake drum bolted to the
transmission main shaft companion
flange, and an external contracting
type band mounted on the rear of
the transmission.
IN-TRUCK ADJUSTMENTS AND REPAIRS
BRAKE SHOE ADJUSTMENT
The brake drums should be at
normal room temperature, when the
brake shoes are adjusted. If the
shoes are adjusted when the shoes
are hot and expanded, the shoes m a y
drag as the drums cool and contract.
A minor brake adjustment rees-
tablishes the brake lining-to-drum
clearance and compensates for nor-
mal lining wear.
A
major brake adjustment in-
cludes the adjustment of the brake
shoe anchor pins as well as the
brake shoes. Adjustment of the an-
chor pin permits the centering of the
brake shoes in the drum.
Adjustment procedures for each
type of brake assembly are given
under the applicable heading.
DUO-SERVO SINGLE
A N C H O R B R A K E
The duo-servo single-anchor brake
is adjusted by turning an adjusting
screw located between the lower
ends of the shoes.
1. Raise the truck until the wheels
clear the floor.
2. Remove the cover from the ad-
justing hole at the bottom of the
brake carrier plate, and turn the ad-
justing screw inside the hole to ex-
pand the brake shoes until they drag
against the brake drum (Fig. 1).
3. W h e n the shoes are against the
drum, back off the adjusting screw
10 to 12 notches so that the drum
rotates freely without drag. If the
drum does not rotate freely, remove
the wheel and drum, and then blow
the dust and dirt from the linings.
With
sandpaper, remove all rust
from the points where the shoes
contact the carrier plate and apply a
light coating of high temperature
grease. Be careful not to get the
lubricant on the linings.
4. Install the wheel and drum,
and adjust the shoes. Install the ad-
justing hole cover on the brake car-
rier plate.
5. Check and adjust the other
three brake assemblies. W h e n adjust-
ing the rear brake shoes, check the
parking brake cables for proper ad-
justment. M a k e sure that there i s
clearance between the ends of the
parking brake link and the shoes.
6. Apply the brakes. If the pedal
travels more than halfway d o w n be-
tween the released position and the
floor, too much clearance exists be-
tween
the brake shoes and the
drums. Repeat steps 2 and 3 above.
7. W h e n
all brake shoes have
been properly adjusted, lower the
truck. Road test the truck and check
the operation of the brakes. Perform
the road test only when the brakes
will apply and the truck can be safo-
UM-SERVO SINGLE
A N C H O R BRAKE
Minor Adjustment The brake
shoe adjustment procedures for the
uni-servo single anchor brake assem-
bly are the same as those for the
duo-servo single anchor type.
Major Adjustment. A major brake
adjustment should be made when
dragging brakes are not corrected by
a minor adjustment, when brake
shoes are relined or replaced, or
when brake drums are machined.
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