San Antonio light. [volume] (San Antonio, Tex.) 1911-1993, 1923-10-21
ADDED MARGIN
Of SAFETY IN
NEW BRAKES
Cadillac Adopts Four
Wheel Brakes Only After
Severe Tests.
NO LOCKED WHEELS
Design Makes Mechanism
Entirely Safe, Engineer
Says.
NO LOCKED WHEELS

margin of safety. Owners are ind
ing that they have in addition brakes
that are more durable and operate
more smoothly. according to Ernest
W. Seaholm, Cadillac chief engineer.
Our engineering division carried on
exhaustive research work and extern
slye experiments over period OF
years. investiga ting practically every
four-whecl braEing system and max
ing actual installations of no less than
IS different devices" states Mr. Sea-
holm. "MoSC Of these installations
were tested b. long, hard drives I'M
der the most trying conditions before
the Cadillac system was finally de-
signel and perfected.
Outstanding safety features in the
Cadillac SYSTEM" he continued, "are
the combination of front internal with
rear external brakes; the correct pro-
por, ion.ng OF the b-aking load between
the front and rear wheels; and provi-
sion for complete control OF front
wheels III steering under all driving
conditions.
The service brake pedal in the veg
simultaneously operates internal
brakes OH the front wheels and ex-
ternal brakes on the rear. By this
combination the effect of the expan-
sion of the front internal brake drums
is ncutralized by the opposite effect
of the expansion Of the drums Of the
rear external brakes.
Friction Is Problem.
All motorists who have toured
mountainous roads not uncOmmOnly
find that the brake pedal-if it oper-
ates external brakes-will apply the
brakes earlier in its travel after brak-
ing down a long grade than at the be-
ginning of the grade. This is the re-
suit of heat from friction which ex-
pands the drums and decreases the
clearances between them and the brake
lining. If the original adjustment is
fairly close, some brakes under such
conditions may seize.
Conversely, n brake pedal which
operates internal brakes will not take
effect as early in the pedal travel
when the brake drums ere hot as at
other times. If the Grake clearance
has become excessive the pedal may
even strike the toe-board before the
brakes take effect.
by combining the two kinds of
brakes, as Cadillac engineers have
dcne in the Veg" continued Mr.. Sea
holm, "the applied position of the
trake pedal hardly changes as the
drums expand.
In the case of front wheel brakes
safety in control is mere important
than maximum ability to stop quick
ly. A front wheel which is sliding
without rotation. has nc power u
change the direction Of the car. Front
wheel brakes must provide against the
contingency of locking both front
wheels on a turn.
Locked Wheel Impossible.
"1Lis is accomplished in the veg
Cadillac by a construction which pro.
vices that when the brakes are ap-
piled with the steering wheel turned
10 the right or left. only the brake on
the inner wheel will take effect, ieav-
ing the outer wheel free TO rotate.
Similarly, if ne car is movrs
straight ahead and the steering wheel
is then turned. the outside front wheel
Is automatically released and con
tinres to rotate, giving the driver
pow to change the direction of the
car. 1t Is impossible for the brakes
TO lock both front wheels on a turn,
10 matter how much pressure is ap-
pied to the pedal
Further provision for safety is
mGde by properly prorortioning the
braking effect between the front and
real wheels. In order that the front
~reels will not lock Until after more
than enough pressure has been ap-
pied TO lock the rear wheels, the
brIkinS effect in front is properly
made less than in the rear.
laird Safety Factor.
1.-The fact that she hand brake Is
divorced in every detail of its mech
anism from tie service hraking system
provides a third factor of safety. In
sbori, the complete hraking system Of
the N-G3 consists of three pairs Of
brakes-front internal and rear OK
1tnIa combined in the four-wheel
brake system Just described, and an
entirely separate set Of internal
brakes acting on the rear wheels and
operated By the hand lever. This
masses a complete reserve brakin.
system.
"T ere is another important ad-
vantage" says Mr.. Seaholm. "that
occurs from the use of internal brakes
on The front wheels. Their use pro-
du an automatic thermal equaliz-
in effect which is sufficient, when
tin car is travelling straight ahead, 20
correct any slight inequality which
may exist in the adjustment of the
front wheel brakes.
If enc front wheel brake has
slightly less clearance than the other,
an takes effect first, the greater
friction will heat and expand the
.rreSponding brake drum. The ex-
pan,.on Of the drum viii increase the
clca' arce slightly and permit the
Tedci to be depressed further until
the other brake takes eject.
H. addition to making every inch
OF 9,dal travel count, Cadillac four |
NEte brakes have been freed from the /
nee! Of frequent attention by increas-
ing the life Of the brake lining.
Load Is Lessened.
The distSbutfon Of the brakipc
dntv among four instead of two
wheels Of itself lessons the load on
each brake. Lining wear is proper
touateIy less than with only two
brakes Not content with this, Cad
lilac eucluccrs have provided n special
type = lining which is highly com.
pressed. formed 10 the shape Of the
drum ara subjected. during manufac.
ture. 70 three distinct heat Treatments.
This lining. moreover, is FURNISHED by
machine before assembling the brake
bands on the axles.