Subaru 2002 Impreza Service Manual page 330

REAR DRUM BRAKES
Brakes
2.
Rear Drum Brakes
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The rear drum brakes are of a leading-trailing shoe type. When fluid pressure is applied to each
wheel cylinder, the piston expands the leading and trailing shoes. During expansion of the shoes,
the lower shoe return spring joint acts as a pivot. The shoes come in contact with the inner surface
of the drum, producing braking action.
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When brakes are applied during the forward movement, the tip of the brake leading shoe lining
is pressed against the inner surface of the drum so as to oppose the drum's rotating force. This
increases the braking force. The trailing shoe, however, undergoes a force that pushes it back so
that braking force applied to the trailing shoe decreases.
The above shoe actions are reverse while the vehicle is moving backward; the braking force ex-
erted on the trailing shoe is greater than that on the leading shoe. This means that there is no differ-
ence in braking force between when the vehicle is moving forward and when it is reversing.
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An inspection hole is provided in the backing plate for easier inspection of the linings for wear.
The hole is closed with a rubber cap.
(1) Wheel cylinder
(2) Upper shoe return spring
(3) Adjuster lever
B R-4
NF0238
(4) Trailing shoe
(5) Leading shoe
(6) Lower shoe return spring