TM 5-3820-239-15
Section XI. AUTOMATIC BRAKES
when specified during preventive maintenance
3-37. General
services.
The automatic brakes used on the pneumatic
a. Remove the screws, nuts, and lock wash-
drill operate independently of each other.
ers holding the brake cylinder cover (fig.
Each brake is designed to be normally on, thus
preventing accidental movement. When the
b. Lift off the brake cylinder cover and
propelling controls are used, some of the air
brake cylinder gasket.
to the propelling air motors is directed to the
c. Screw two 5/8-inch coarse thread bolts
brake (fig. 1-3), thus releasing it. During
into the holes in the top of the brake piston,
towing, the brake can be manually released by
and remove the piston from the cylinder.
turning in (clockwise) the setscrew at the top
of each brake housing.
Caution: Be careful not to damage the
brake piston O-ring.
3-38. Brake Admustment
d. Using a 1 1/4-inch socket wrench, adjust
the brake bolt until the working length of the
There is no method of checking the brake
brake spring (measured from the bottom of the
adjustment without actually making the adjust-
cylinder to the top of the brake spring) is 3
ment. Unless a trouble is encountered during
1/2 inches (fig. 3-14).
operation which pinpoints the brakes as the
trouble source, perform the adjustment only
