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P A R T 2-3-F-250 AND F-350, AND P-SERIES BRAKE SYSTEMS
2-17
l. Raise the truck until the wheel
clears the floor.
2. Rotate the drum until the feel-
er slot i s opposite the lower end of
the secondary (rear) brake shoe.
3. Insert a 0.010-inch feeler gauge
through the slot in the drum. M o v e
the feeler up along the secondary
shoe until i t is wedged between the
secondary shoe and the drum.
4. Turn the adjusting screw (star
wheel) to expand the brake shoes
until a heavy drag is felt against the
drum. Back off the adjusting screw
just enough to establish a clearance
of 0.010 inch, between the shoe and
the d r u m at a point P/2 inches from
each end of the secondary shoe. This
adjustment will provide correct op-
erating clearance for both the pri-
mary and secondary shoes. If the
0.010-inch clearance cannot be ob-
tained at both ends of the secondary
shoe, the anchor pin must be ad-
justed.
5. T o adjust the anchor pin set-
ting, loosen the anchor pin nut just
enough to permit moving the pin up
or d o w n by tapping the nut with a
soft h a m m e r (Fig. 2).
D o not back the nut off too far or
the shoes will m o v e out of position
w h e n the nut is tightened. T a p the
anchor pin in a direction that will
allow the shoes to center in the
drum
and provide
an operating
clearance of 0.010 inch (Fig. 2).
Torque the anchor pin nut to 80-
100 ft-lbs. Recheck the secondary
shoe clearance at both the heel and
toe ends of the shoe. Install the ad-
justing hole cover.
6. Check and adjust the other
brake assemblies.
7. W h e n all brake shoes and an-
chor pins have been properly adjust-
ed, lower the truck. Road test the
truck and check the operation of the
brakes. Perform the road test only
w h e n the brakes will apply and the
truck can be safely stopped.
TWO-CYLINDER BRAKE
T h e two-cylinder brake assembly
brake shoes are adjusted by turning
adjusting wheels reached
through
slots in the carrier plate.
T w o types of two-cylinder brake
assemblies are used on truck rear
wheels. T h e assemblies differ pri-
marily in the retracting spring hook-
up, and in the design of the adjust-
ing screws and locks. However, the
service procedures are the same for
both assemblies.
T h e
brake adjustment is m a d e
with the truck raised. Check the
brake drag by rotating the drum in
the direction of forward rotation as
the adjustment i s made.
1. R e m o v e the adjusting slot cov-
ers from the carrier plate.
2. Turn the rear (secondary shoe)
adjusting screw inside the hole to ex-
pand the brake shoe until i t drags
against the brake drum.
3. Back
off the adjusting screw
so that the drum rotates freely with-
out drag. Depress the brake pedal to
center the brake shoes, and back off
the adjusting screw an additional
notch to provide operating clearance.
4. Repeat the above procedure on
the front (primary) brake shoe.
5. Replace
the adjusting
hole
covers.
PARKING BRAKE
ADJUSTMENT—CABLE
ACTUATED REAR WHEEL
PARKING BRAKES
Adjust the service braJkes before
attempting
to adjust the parking
brake cables.
Place the parking brake lever in
the fully
released
position, then
check for slack in the parking brake
two rear cables (Fig. 3).
The cables should be tight enough
to provide full application of the
rear brake shoes, when the parking
brake lever is placed in the fully
applied position, yet loose enough to
ensure complete release of the brake
shoes when the lever i s in the re-
leased position.
If the cables are loose, adjust
them as follows:
1. Loosen
the locknut on the
equalizer rod, and then turn the nut
in front of the equalizer several
turns forward.
EQUALIZER LEVER
EQUALIZER ASSEMBLY
LOCK NUT
H1007-A
FRONT NUT
EQUALIZER ROD
HI173-A
FSG. 2—Anchor Pin Adjustment
FIG. 3—Parking Brake Cable Adjustment
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