Saab 95 1967, Руководство по обслуживанию

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FUNCTION
When the brake pedal is depressed, the master cylinder
pistons apply a force to the brake fluid, which is trans-
mitted through brake pipes and hoses to the pistons of
the brake cylinders, causing the brake pads to contact
the brake disc and the brake linings the drums. The mas-
ter cylinder has two pistons which work simultaneously,
but independently, so that one acts on the left front and
right rear wheels while the other acts on the right front
and left rear wheels. Consequently, if leakage occurs in
one circuit, the piston in the damaged circuit moves with-
out affecting the brake pads.
Every application of the brakes thus pumps a certain
amount of brake fluid out of the system, but as the upper
part of the brake cylinder forms two chambers separated
by a partition, the system can only be emptied as far as
the partition. The brake fluid remaining for the undam-
aged circuit is sufficient to allow the car to be driven safe-
ly to a garage to have the damage repaired. Since the two-
circuit brakes operate on the diagonal wheels, always
approx. half the braking effect remains at leakage in one
circuit. Furthermore, this affords greater safety when
steering the car, as one front wheel and one rear wheel
roll freely at the same time and are not locked.
MASTER CYLINDER
LHD up to and incl model 1970, RHD up to and incl
chassis No. 96722017570 and 95722006474.
The tandem master cylinder comprises a body housing, a
primary piston and a secondary piston, which are ac-
tuated by the push-rod from the brake pedal. The distance
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between the pistons is determined by a Spiriil spring and
a wire clamp. The semndary piston has a primary uép
and a secondary cup at front and rear respectively. rtteo
behind the primary cup is a dished piston washer, which
prevents the cup from being extruded into the feed notes
in the piston flange. The primary cup of the pnmary pm.
ton also has a dished piston washer and a secondary, rear
cup. _
The spiral springs return the pistons to the lmtlal posmon,
In their initial position, the pistons are retained by the
spring pressure and as a consequence the channels open
between the fluid container and the master cyllnder.
When the brake pedal is depressed, the push-rod actuates
the primary piston, making the inlet channel between
fluid container and cylinder close, and the pressure In
front of the primary piston rise which in turn affects the
secondary piston making it move and in this way the
same overpressure is obtained in front of both pistons.
Now brake fluid is forced out through the brake lines to
the wheel cylinders and puts the brakes into action.
If a leakage occurs in the brake circuit served by the pri-
mary piston, the spring is compressed until the primary
piston contacts the secondary piston. Then the latter can
work normally.
At a leakage in the secondary piston circuit, the secon-
den/piston is pressed forward by the primary piston and
the spring, until the secondary piston strikes the bottorn
of the cylinder. Then, brake fluid can be pressed out into
the undamaged circuit,
LHD as from model 1971 RHD as from chassis No.
96722017571 and 95722006474.
The pistons are equipped with three seals on each, and
the distance between the pistons is determined by a
spiral spring and a screw.
7.
$5911