BENDIX PP-1-2-5-8-RD-3 PUSH-PULL VALVES Manual

®
® ™
Bendix PP-1 , PP-2
Control Valves
™
PP-1
VALVE
FIGURE 1 - PUSH-PULL TYPE CONTROL VALVES
DESCRIPTION
The PP valves are push-pull manually operable on-off air
control valves with an exhaust function. Most are pressure
sensitive, so that they will automatically move from the
applied to the exhaust position as supply pressure is
reduced to a certain minimum, depending on the spring in-
stalled. The exception to this is the PP-8
™
PP-1 valves which have no spring. The PP-8
has a larger diameter shaft for button mounting so that when
installed on the same panel with other PP valves the
buttons cannot be inadvertently mixed. The PP-8
normally used to operate tractor spring brakes independently
from the trailer.
™
The PP-5 valve is unique in having an auxiliary piston in
the lower cover which, upon receiving a pneumatic signal of
18 psi or more, will cause the valve to move from the applied
to the exhaust position from a 100 psi application.
™
The RD-3 valve differs slightly in that it normally remains in
the exhaust position and requires a constant manual force
to hold it in the applied position.
™ ™ ™
, PP-5 , PP-8
PP-2 ™
VALVE
™ valve and some
™
valve also
™
valve is
™
, & RD-3 Push-Pull Type
™
PP-5
VALVE
™
The PP-2 valve has an auxiliary port which may be plumbed
into a service brake line to release the spring brakes if a
service application is made, preventing compounding of
forces on the foundation brakes.
PREVENTIVE MAINTENANCE
Important: Review the Bendix Warranty Policy before per-
forming any intrusive maintenance procedures. A warranty
may be voided if intrusive maintenance is performed during
the warranty period.
No two vehicles operate under identical conditions, as a
result, maintenance intervals may vary. Experience is a valu-
able guide in determining the best maintenance interval for
air brake system components. At a minimum, the PP valves
should be inspected every 6 months or 1500 operating hours,
whichever comes first, for proper operation. Should the PP
valves not meet the elements of the operational tests noted
in this document, further investigation and service of the
valve may be required.
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RD-3
VALVE
™
PP-8
VALVE
1