Volvo VNL 780 Operator's Manual page 317

DANGER
Automatic slack adjusters MUST NOT
be manually adjusted in an effort to
correct excessive push rod stroke, as this
condition indicates that a problem exists
with the automatic adjuster, installation of
the automatic slack adjuster or problems
related to components of the foundation
brakes. These conditions will not be
corrected by manually adjusting the
automatic slack adjusters.
Manual adjustment of the automatic slack
adjusters is a dangerous practice that
could result in serious consequences. This
practice gives the vehicle operator a false
sense of security about the effectiveness
of the brakes, and the brakes will likely
soon be out of adjustment again.
General
All Volvo vehicles are designed to meet or exceed all applicable federal brake standards and
regulations. They use a dual circuit, compressed air system. It consists of two independent
brake systems that use a single set of brake controls. Each circuit is supplied by its own
compressed air tank. Both air tanks receive compressed air from the same supply tank
(wet tank) and are charged with equal pressure. The two circuits are interconnected for
the parking brake system.
DANGER
DO NOT release the parking brake or
attempt to move the vehicle until brake
air pressure in both circuits is at least
690 kPa (100 psi). Failure to follow
this procedure may lead to uncontrolled
vehicle movement and cause severe
personal injury or death.
OPERATION 307