SPECIFICATIONS

Vehicle Systems Systems Operation
When the brake action first starts, primary shoe (15)
comes in contact with the brake drum as it is in rota-
tion. This contact of the primary shoe puts some
force on secondary shoe (16) to help put it in posi-
tion against the drum.
When the brake pedal is released the brake shoe
springs pull the brake shoes and push wheel cylinder
pistons back into wheel cylinder (12). The liquid is
pushed from the wheel cylinder back through master
cylinder outlet and into the master cylinder.
The brakes will automatically adjust themselves with
a forward or reverse brake application. In the above
example. The drum rotation is counterclockwise in
forward which causes a counterclockwise rotation of
the brake shoes. As the shoes are pushed out
against the drum, guide (20) will move axially. This
causes a swing movement of plate (24). The dis-
tance that the plate swings is controlled by the slots
in the plate and pins (23) and (27). If there is enough
wear, plate (24) will engage the next tooth of star
wheel (21).
When the brakes are released, return springs (17)
and (18) will bring the brake shoes back to their rest
position. Springs (19), (25) and (26) will bring the
adjustor back to its original position. The star wheel
is turned one tooth and adjustment screw (21), which
is engaged with the primary shoe web, is turned out.
The brake shoe has a new position after the
adjustment.
Oil Cooled Disc Brakes
Disc Brake Assembly
(1) Inlet (from master cylinder). (2) Passage. (3) Plates (five).
(4) Discs (four). (5) Piston. (6) Seal. (7) Seal.
When the brake lever is pulled, the master cylinder
pushes brake liquid through the master cylinder out-
let, the brake lines, to inlet (1) of each disc brake
assembly. Liquid flows through inlet (1), passage (2)
and pushes on piston (5). Piston (5) pushes against
plates (3) and friction discs (4) to stop any movement
of the lift truck. The five separator plates (3) are
splined to the wheel cover and the four friction discs
(4) are splined to the hub. During brake activation
the piston seals (6) and (7) are deflected by the
brake piston movement.
When the brake pedal is released, the brake liquid
pressure is released and seals (6) and (7) return to
their original position. This seal retraction gives the
running clearance needed between plates (3) and
discs (4). This action will release the brakes on the
lift truck. As the seals retract brake liquid is returned
to the master cylinder. The piston automatically
slides outward from the cylinder bore as the friction
discs wear. This new location then becomes the
beginning or at rest position of the seals. This will
maintain the proper clearances of the discs and
plates.
18
1
5
6
7
4
3
2
IDCS117S