Capital journal. (Salem, Or.) 1919-1980, 1921-05-21
Neglect Of
Rear Axle
Expensive
Constant Attention
Necessary to Insure
Freedom From Much
Trouble

Trouble
Among the hardest working
units DIN the mechanism OF the
modern motor car is the rear axle.
The function of this part is not
only to help carry the weight Of
the car but also to transmit the
power. Whenever the car is in
motion the rear axle is the scene
Of intense mechanical activity. II
will be obvious then that this part
of the mechanism should have the
most scrupulous care. 1t does not
always get 1t, as we shall point out
in the course OF tnis article.
Rear axles fall readily into two
distinct classifications, dead axles
and live ones It is live axles
which are used on all modern pas
genger cars. The term live" sim
ply means that the axle turns.
Dead axles do not turn and they
arc only used on vehicles having
double chain drive.
When we come to examine live
axles we find'it necessary to classiT
fly them stin further into three
minor classes, known respectively
as floating, semi-floating and
three-quarter floating. A further
classification comes later, accord
ing to the type of gearing used to
transmit the power.
The live axle consists principal
1y OF a hollow spheroid, from
which project on either side two
tubes. In the central spheroid Is
located the differential unit em-
bodying a number of gears. From
the dlfferential project two shafts,
which occupy the tubes projecting
from the central spheroid OF the
rear axle. AT the ends Of these
shafts the wheels are attached.
The classifications OF floating,
semi-floating and three-quarter
floating are derived from the
method used In attaching the
wheels to the shafts
The floating axle does do very
nearly that thing. 1t is not called
upon to bear any OF the weight OF
the car, 1t simply transmits the
power to the wheels and takes a
little OF thet orsional or twisting
stresses. The floating axle hasjts
bearings outside the tube, so that
the wheels really rest on the tubeO
and not on the shafts. In this
type OF axle the shafts may be re-
moved without disturbing any
other parts.
The semi-floating axle has its
bearings on the inside of the tube,
so that the shafts are called upon
to bear some of the load as we'll as
to transmit power. The shafts are
not as easily removed as in the
case OF the floating axle.
The three-quarter floating axle
has the ebaring on the outside Of
the tubes and there is a rigid con-
nection between shafts and wheels.
This type demands that the shafts
shall bear some OF the load in addi-
tion to transmitting power.
When it comes to the types of
gears used In transmitting power,
we find that the passenger cars OF
today employ three, straight beyel,
spiral bevel ami two-speed bevel.
In the truck field we find three
types. the worm intern
Al gear and double chain drive,
though the latter is growing less
every year. During the last few
years the spiral bevel has come
rapidly to the front, until today It
Is the popular type. There are
obvious reasons for this, its quiet
and general efficiency be-
ing the leading ones. Many maxi
srs still stick to the straight bevel |
while the two-speed bevel has only |
,ne prominent adherent.
The car owner who has exper-
enced that most tenacious trouble
known as rear axle
rouble" win not need the advice
% do everything possible to guard
against Il. Many serious troubles
nay develop in this unit aud only |
he utmost care will obviate some
If them. Axle shafts sometimes
break or are twisted out of their
,roper shape. Bearings are some
lines crushed. The difterential
rears are peculiarly liable to chip
ling. which may very probable re-
Iult in the ruin OF the whole unit.
AS is generally the case the
item In the proper care
4 the rear axle is fabrication.
tever make the mistake OF using
irease In this part. as used to be
be rule. oil is the proper lubrica-
ion for the rear axle. Once or
vice durlng the running season
he rear axle should be drained,
nda fter being flushed with kero-
ane fresh oil should be put In.
fote also that while the part
louId be kept well filled with oil
Il the time. an excess Is not de-
rable, for the extra quantity is
kelly to work down into lheI
-aking system. with the funct-
ming OF which it interferes.
,meumes Il Is necessary TO place
It washers in the axle tubes TO
event the excess oil working out
this way. Many modern cans