Single Piston Floating Caliper Type; Clearance Correction - Suzuki Samurai 1986 Service Manual

[Caliper OPERATION]

Single piston floating caliper type

The single piston floating caliper type brake is
employed in this model. One cylinder and one
piston are used for this type. (The cylinder is
constructed as a monoblock with the caliper.)
Fluid pressure generated in the cylinder causes
the pad (1) on the piston side to press against
the disc. At the same time, the floating type
caliper body is moved to the right by the cylin-
der pressure, as shown in below figure, which
pulls pad (2) against the disc and so brakes the
wheel.
F i g . 1 9 - 6
The disc brake has no servo assistance as in drum
braking, and it is necessary to increase the work-
ing pressure of the piston and pad. For this pur-
pose, the wheel cylinder has a large bore. Even
only a little change in clearance between the disc
and pad has therefore a large influence on the
brake pedal stroke. It is necessary to have the
clearance adjusted to the minimum at all times,
by means of the piston (rubber) seal.
body
Brake disc (rotor)
Piston seal
Cylinder
(Rubber seal)
Piston
Hydraulic pressure
"OFF"
Fig. 19-7

Clearance correction

When oil pressure is applied to the piston, the
piston moves forward. The rubber seal, which
exerts considerable pressure against the piston,
moves with the cylinder. However, as a part of
the rubber seal has been fixed into a groove in
the cylinder, the shape of the rubber seal is dis-
torted toward internal end of the cylinder, as
shown in above figure. When pressure is taken
off from the foot brake pedal and fluid pressure
is released from the piston, a restoring force is
generated at the seal and pushes the piston back.
As the pads wear away and the clearance be-
tween the disc and pads becomes larger, the
piston moves a larger distance. The seal then
could change in shape further but, since the end
of the seal is fixed into the groove in the cylin-
der, the distortion is limited to the same amount
as previously described. The piston moves
further to cover the distance of clearance. The
piston returns by the same distance and the
rubber seal recovers its shape as described
above and thus the clearance between the disc
and pads are maintained in adjustment.
Piston seal
Winder (Rubber seal)
I
Piston
Hydraulic pressure
"ON"
19-7