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F) Slack adjuster
Braking system – checking and adjustment
S-cam brakes with manual slack adjusters
Due to normal brake drum and brake lining wear, the wheel brakes must be regularly adjusted in order to
maintain the full brake cylinder stroke. To ensure maximum brake efficiency, the clearance between brake
lining and drum must be kept to an absolute minimum. To determine this clearance, check the brake cylinder
stroke while full pressure is applied to the service brake. If the path at the yoke end measures more than 2/3
of the maximum cylinder stroke then the brake must be adjusted without delay. With a correctly adjusted
brake, it should be impossible to move the piston rod by hand more than 15 mm.
Turn adjusting screw to the
right until...
... the brake shoes fit closely
to the brake drum.
Turn adjusting screw to the
left, until...
... the no-load stroke at the
slack adjuster (at 127 mm) is
approx. 10 - 15 mm long.
The wheel must rotate freely
with no grating noise.
No-load - absolu-
tely no play is
permissible bet-
ween the piston
and membrane.
Adjusting screw
(width across flats 19 mm)
Special instructions for automatic slack adjusters are given on the following pages.
A = At 1/2 stroke, the angle must not exceed 90°.
B = On full brake application, the slack adjuster and axle beam must not come in contact
with each other.
L = Inspect piston rod according to technical specification.
