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COUPE
FRONT BRAKE SPECIFICATIONS
285
Front wheel brakes
Disc diameter
Working area
. . .
Caliper piston diameter
Working clearance of self-adjuster friction ring
Minimum thickness of disc after grinding
Minimum permissible thickness of disc from wear
Minimum thickness of lining pads . . . . . . . .
Free travel of brake pedal (for master cylinder operation)
Total travel of brake pedal . . .
Hydraulic brake fluid
I
~i~~~t ~a~a~it~:
: : : : : : : :
disc type with lining pads
controlled
by
a wheel cylinder
8.898" (226 rom)
20.46 sq.in (132 cm')
1.772" (45 rom)
.0236" to .0285" (0.600 to 0.725 rom)
.374" (9.5 rom)
.354" (9 rom)
.079" (2 rom)
.063" (1.6
rom)
5.945" (151 rom)
FIAT special \( blue label
I!
fluid
.493 pts (G.B.) - .592 pts (U.S.) (0.28 It)
Description.
The disc brake of each front wheel consists of:
- a disc rigidly mounted to the wheel hub;
- a plate rigidly mounted to the steering knuckle,
for anchor of caliper mounting bracket
j
- a caliper mounting bracket equipped with two
clamps retaining the bracket laterally and pivoted
to it by pins;
-
- a one-piece caliper which houses the wheel
cylinder piston and two lining pads; in caliper
interior is also inclosed the automatic adjusting
device;
- a splash shield protecting the disc side op-
posite the wheel from foreign material.
Operation.
When the hydraulic pressure is established by
depressing the brake pedal, the wheel cylinder
piston moves on and causes the adjacent lining to
come in contact with the disc. Simultaneously with
the above described functions, reaction creates an
even and opposite force which moves the caliper
axially on the bracket and the outer lining comes
into contact with the disc.
Now, as the hydraulic pressure increases, the
braking action will take place and the effort is
shared by both linings, reSulting in equal wear and
effective braking.
Upon release of the brake pedal hydraulic pres-
sure is annulled and the piston is apt to return to
rest position.
However, piston back travel is
restrained by the automatic adjusting device as
outlined hereafter.
Fig. 448 - left side front
wheel
disc
brake assembly.
Brake Lining-to-Disc Clearance Self-
Adjusting Device.
This device assures good braking under all con-
ditions by maintaining a constant clearance between
the linings and disc.
It ensues that, as the front
brakes are set by themselves, action must be made
solely on rear brakes when the brake pedal travel
needs adjustment.
The self-adjuster is assembled into piston (4,
fig. 451) and works in fluid bath.
It consists of a
steel ring (9) which is sliding with a certain friction
in piston interior.
The friction ring (9) is tied to the pin (6) rigidly
mounted to the caliper body (I) by means of two
washers (8-10) which are secured to the pin through
a spacer
(II).
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