Cadillac 60 Series 1963 Shop Manual page 166

BRAKES
GENERAL DESCRIPTION
The braking system used on all 1963 Cadillac
cars consists of power-assisted, hydraulically-
operated front and rear service brakes and a
foot-operated, vacuum-released parking brake
that applies the brake shoes at the rear wheels
through mechanical linkage.
Two different power brake units are used in
1963 production: Bendix and Delco Moraine.
These units are similar in outward appearance
and operation but vary considerably in internal
construction. For identification the Bendix unit
is painted all black, while the vacuum cylinder
of the Delco Moraine unit is zinc plated.
Both power brake units are of the vacuum sus-
pended diaphragm type, utilizing engine intake
manifold vacuum and atmospheric pressure to
provide power-assisted application of the hy-
draulic .service brakes. The power units are
composed of two main sections; a vacuum power
section and a split system type hydraulic master
cylinder.
The vacuum power section of both the Bendix
and Delco Moraine units, Figs. 8-1 and 8-2, con-
sists of a front and rear shell, a power piston
assembly that houses the control valve assembly
and reaction mechanism, a vacuum power dia-
phragm, and a power piston return spring. The
control valve assembly consists of a single poppet
with a filtered atmospheric port and a vacuum
port. The reaction mechanism, integral with the
power piston assembly, controls the degree of
power brake application or release in accordance
with pressure applied to the valve operating rod
through the brake pedal linkage. The reaction
mechanism in the Bendix unit consists of a rubber
disc whereas, a reaction plate and levers are
used in the Delco Moraine unit.
The master cylinder in both types of power
units is designed so that the front and rear brakes
have separate hydraulic systems. The primary
(rear) section of the master cylinder provides
fluid for the front brakes, while the secondary
(front) section provides fluid for the rear brakes.
Should a leak occur in the front wheel hydraulic
system, the rear lines and wheel cylinders would
still function. Likewise, if the rear hydraulic
system should leak, the front brakes would still
function. Increased pedal travel would warn the
driver that such a condition had occurred.
A Vacuum check valve at the inlet to the power
unit permits several applications of the brakes
with vacuum assist after the engine has stopped
or after any other loss of vacuum supply. When
Compensating Port
Inlet Port
Seal Ring Front Shell
Fluid Reservoirs p;
ston
stop And I / __
Seal Assembly / f
t
Rear Shell
^ W : V . - ^ ll I!
Secondary Piston
Piston Seal
Compensating Holes
Hydraulic ,.'
Push \
"' sr
^
l
« ^ ' 1
V
l ^ " ^ r \
p u s h R d
' ' ^ ^ • B i i s c a j ^ ^
sllencer
'jJ^Blii
Dust Guard
Check Valve
Power Diaphragm
Power Diaphragm Return Spring
Power Piston
Fig. 8-1 Bendix Power Brake Unit