(2) Manual bleeding.
(3) Pressure Feed Filler Bleeding.
(a) Connect trailer service brake hose to a
(a) Remove the filler cap from the master
cylinder.
towing vehicle (fig. 2-2) for manual bleeding as the
brake pedal must be pressed and released to actuate
(b) Connect a hose to a pressure feed filler
using a proper size adapter, to the opening in the
the brake system. The master cylinder must be kept
master cylinder.
full of brake fluid or air will enter the system.
(b) Clean the bleeder valve (fig. 4-31 ) with a
(c) The pressure filler must contain from 10 to
20 psi air pressure and sufficient fluid to maintain
clean cloth. Attach a bleeder hose to the bleeder
valve and place the other end of the hose in a suitable
constant fluid level in the master cylinder.
container.
(d) Proceed to bleed the system as in manual
bleeding ((2 above).
(c) Fill the master cylinder with brake fluid.
(d) Pump brake pedal on towing vehicle until
(e) Replenish fluid in the master cylinder after
bleeding, if necessary.
pressure is applied. Hold pedal pressure and open
bleeder valve (fig. 4-31) until pressure is released on
4-43. Wheel Cylinders and Brake Shoes
pedal, then close bleeder valve.
a. Removal.
(e) Repeat this action until fluid has replaced
(1) Release the brake air pressure by opening
air in the system, then close the valve and remove
draincock (fig. 3-5), at the air reservoir.
the bleeder hose.
(2) Remove three screws (1, fig. 4-30), washers
(f) Refill master cylinder and install the filler
cap.
(2), cap (3), gasket (4), nut (5), lock (6), nut (7), and
bearing cone (8) securing the wheel and drum assem-
(g) Repeat this operation on the opposite
bly and remove wheel and drum.
wheel.
(3) Remove the wheel cylinders and brake shoes
CAUTION
as illustrated in figure 4-32.
Maintain a high level of fluid in the
master cylinder while bleeding each
wheel cylinder.
4-42
