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J5;r
SINGLE CIRCUIT FLAP- VALVE MASTER- CYLINDER
4
Description (Fig. 5)
The flap valve •aster-cylinder, also known as a
central re-feed!ng master-cylinder, Is comprised
of:
A cast Iron body (A) Including:
• a bore,
• a fastening flange,
• a feeding boss (l), on which the equalizer
tank Is screwed, and which Incorporates a
fitted 4 m• dla. Mecan!ndus pin (2)
providing a connection between the braking
system and the equalizer tank,
• a connection for the front brake system (3),
, a connection for the rear brake system (4).
- A die-cast light alloy piston (8), comprised of:
• a primary cup (5),
, a secondary cup (6).
A feature of this piston Is that it Incorporates
a channel, which enables
it
to slide
longitudinally over the Mecanindus pin, and a
central drilling in Its front section to
accom~odate
flap valve (C).
- A flap valve (C) comprised of:
• a bracket (7),
• a spring (8).
- A piston return spring (D).
-An anti-emulsion valve
(E)
or residual pressure
dummy valve.
Note: this master-cylinder incorporates neither
a snap-ring, nor a thrust washer.
In the rest
position, the piston bears against the
Mecanindus pin.
Operation
When
the driver'presses or. the brake
pedal, piston
(B)
moves towards the bottom of the
bore.
Fig. 5
CHRYSLER
160
-
160
GT •
180
In so doing, It
drives also
primary cup
(s)
and
flap valve bracket
(7).
Flap valve (C), under the effect of its spring (8),
remains stationary, and comes into contact
with
its
seat (9).
During this first displacement, which is very
short,
there Is no increase In pressure,
and a
small
quantity of fluid is discharged through the
piston
central drilling, then via pin (2) towards the
equal! zer tank.
From that Instant, the piston Initiates a
displacement of the column of fluid towards the
receiver cylinders, and generates an Increase in
hydraulic pressure, which is In
proportion
to the
pressure
applied
on the pedal •
When the brake is released,
the hydraul
fc
pressure
Is cancelled, the piston
and flap
valve
return unde
r
the effect of return spring
{D).
As a first
stage,
the vacuum,
which
Is generated
at
that instant, opposes the force of flap valve
sp
ri
ng
(8):
the flap valve, then, remains open,
and the
circuit is, therefore, made
im
m
ediately
complete:
then, the piston reaches Its rest position,
th
e fl
ap
valve reaches its stop position,
and provides a fr ee
communicat
i
on between the
supply system and t he
braking system.
Note:
the
flap-valve
master-cyl
ind
er provides
several
Improvem
ents
In relation to conventio
nal
master-cylinders.
It does
not
include an
expansion hole, and
the
fi sk
of scratches appearing on the
pri
mary cup Is
,
therefore,
ellm 1nated.
As
soon
as
t
he
brake
pedal
Is
released, ,·e-
feedln
g
takes pl
ace
im
mediately
through
t he fl
ap valve
opening, w
hich
r educes
the vacuum
cons
iderab
l
y,
and
thus eliminates the risk of
air
penetrating
in
the
system.
G.064
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