(5) If a pressure bleeder is used, permit the fluid
2-54. Brake Power Booster
to drain from the bleeder hose until no bubbles appear
a. General. The brake power booster is connected
in the fluid. Then close the bleeder screw.
to the master cylinder outlet through a pipe nipple
(6) If manual bleeding is being employed, slowly
and is operated by pressure produced in the master
depress the brake pedal to the stroke limit, close the
cylinder. It multiplies the pressure produced in the
bleeder screw, and then release. Repeat until no
master cylinder end applies this increased pressure to
bubbles escape from the bleeder hose. Keep the pedal
the wheel cylinders, resulting in more positive braking.
depressed after the final stroke and quickly close the
b. Removal. Refer to figure 2-38 and remove the
bleeder screw so that no air enters the system.
power booster as follows :
(1) Remove the floor plate.
Manual bleeding quickly depletes the fluid supply in the
(2) Disconnect the brake line at the power
reservoir. Continually check the fluid level and keep the
reservoir at least 1/2 full et all times or air will enter system.
(3) Using an open-end wrench of the proper size,
(7) Repeat the bleeding procedure at the remain-
hold the connecting nipple to the master cylinder
ing wheel cylinder and then at the power boo&r.
while removing the power booster.
(8) When the bleeder operation is complete refill
the master cylinder reservoir to the proper level.
(1) Reverse procedures in b above.
(2) Use a suitable thread compound on thread
connections and make sure connections are tight.
Fluid salvaged from the system during the
(3) Bleed the brake system (para 2-53).
bleeding operation is aerated and is no longer
suitable for use in this system.
Section XIV. MAINTENANCE OF THE WHEELS
the mast assembly and then tilting the mast to the
The drive wheel rim and tire assembly consist of
(2) Remove the 3-segment wedge ring (7) figure
2 wheels, 2 tires, and tubes. The steer wheel assemblies
consist of a wheel, tire and tube, and bearings.
(3) Slide the outer tire and rim assembly from
2-56. Drive Wheels
(4) Remove the rim spacer and then the inner
tire and rim assembly.
(1) Raise the front of the truck so the wheel
b. Installation. Reverse procedures in a above.
clears the floor. This may be done by tilting the mast
to full backward position and inserting a block under