Brakes; General Description; Service Information; Brake Seals - Cadillac 1937 LaSalle VVI Information

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BRAKES
General Description
The b r a k i n g system on the 37-series C a d i l l a c
and LaSalle cars comprises service brakes of
the hydraulic type combined w i t h a hand lever
that operates the rear brake shoes through a
mechanical linkage. A v a c u u m brake assister is
used on the 37-90 V - 1 6 Cadillac.
The service brake system consists of a combined
fluid supply tank and master cylinder, i n which
the hydraulic pressure is originated; four wheel
cylinders i n which the pressure is applied to
operate the brake shoes against the wheel d r u m s ;
and the tubing and flexible hoses connecting the
master cylinder to the wheel cylinders.
The combined supply tank and master cylinder
is mounted on the frame beneath the left front
floorboards, except on 37-90 where i t is j u s t behind
the steering gear. T h e m a i n function of this unit
is to maintain a constant volume of fluid i n the
system at a l l times, regardless o f expansion or
contraction due to temperature changes. It also
serves as a p u m p when bleeding the brake lines.
The compensating action of this unit can be
understood b y referring to P l a t e 22 F i g . 5. W h e n
the pedal is depressed, the piston p r i m a r y cup
immediately closes the by-pass port and builds
up pressure i n the system. W h e n the pedal is
released, the return of the piston a n d p r i m a r y
cup is m u c h faster t h a n the return of the fluid to
the master cylinder.
Consequently, a momentary v a c u u m is created,
which draws a d d i t i o n a l fluid into the system
through the drilled holes in the piston and past
the lip of the p r i m a r y cup. T h e n , when the
retracting springs fully release the brake shoes,
the excess fluid i n the master cylinder passes up
through the by-pass port and the entire system
is ready for the next brake application.
T h e wheel cylinders are of the double piston
type. T h e cylinder casting is mounted o n the
brake dust shield, while each of the two pistons
is connected to one of the brake shoes b y means of
a link. Pressure of the fluid in the wheel cylinder
when the brakes are applied causes the pistons to
move i n opposite directions, thus forcing the
brake shoes into contact w i t h the drums. Pressure
cannot be built up i n the system u n t i l a l l shoes
are in contact w i t h their respective drums.
T h e front wheel cylinders have a larger diameter
than the rear cylinders; consequently, the front
and rear cylinders are not interchangeable. T h i s
arrangement of the wheel cylinders gives a higher
braking ratio on the front wheels than on the rear.
(See Specifications.)
T h e pistons i n the master cylinder and i n the
wheel cylinders are provided w i t h cup packings
which act as seals to prevent the loss of brake
fluid and, consequently, of braking pressure.
T h e hand brake lever is mounted under the
instrument panel at the extreme left. It is con-
nected b y a steel cable to a lever mounted on
the frame X - m e m b e r . F r o m this lever cables
extend to each rear brake, where they actuate the
brake shoes by means of a curved lever and strut
rod.
M o u l d e d brake lining is used on both primary
and seconadry brake shoes of a l l 37-series cars
except the V-16, which has moulded lining on
the primary shoes and woven lining on the
secondary, shoes.
T h e brakes of a l l 37-series Cadillac cars are
protected from water, dirt, or other foreign
matter b y a brake seal mounted around the out-
side edge of the brake dust shield as shown in
P l a t e 22, F i g . 1.
Service Information
1. Brake Seals
T h e brake seals that are installed on 37-series
Cadillac cars must be removed whenever any
work is done on the brakes that requires removal
of the brake drums.
R e m o v a l of these seals is easily performed by
expanding the seal and lifting it from the dust
shield after removing the nut on the clamp
screw where the two ends of the seal are fastened
together. See P l a t e 22, F i g . 1. Installation can
be made b y reversing the above procedure.
2. Brake A d j u s t m e n t (Service Brakes)
1. M a k e sure that hand brakes are fully
released.
2. J a c k u p car, dismount all four wheels, and
remove the inspection hole covers from the brake
d r u m and dust shield.
3. A t each wheel loosen the lock nut at the
eccentric adjustment. (See Plate 23) Insert a
.010-inch feeler gauge between the lining on the
secondary (rear) brake shoe and the drum.
4. Clearance between the lining and the d r u m
can be taken up to the required .010 inch by
turning the eccentric in the direction of forward
wheel rotation. C h e c k the clearance at both ends
of the brake shoe and, if there is more than .002
variation, the anchor p i n must be readjusted.
5. T o readjust the anchor pin, loosen the lock-