Troubleshooting guide

28
www.bendix.com 1-800-AIR-BRAKE (1-800-247-2725)
SR-1
™
Spring
Brake Valve
Service Relay
Valve
QR-1C
™
Quick
Release
Valve
PP-DC
™
Park
Control Valve
Miscellaneous Charging System Related Components
Park Control Valves
The PP-DC
™
park control double check valve is a
push-pull, manually operable on/off valve with an integral
double check. It is dashboard mounted and provides
in-cab control of truck or bus parking brakes. Manually
pushing or pulling the button will release or apply the
parking brakes. The integral double check valve allows
the PP-DC
™
valve to receive supply air pressure from
either, or both, the front or rear axle service reservoirs.
The valve is pressure sensitive and automatically moves
from the applied (over the road position) to the exhaust
position (thus applying the parking brakes) if total
system pressure (both front and rear axle reservoirs)
drops below 20 to 30 psi.
Section 4: Tractor Parking, Trailer Charging/Parking and
Emergency Systems
The tractor/trailer parking and emergency system
typically consists of:
• The tractor parking control system
• The trailer parking and emergency system, and
• The tractor protection system
See the inside front cover for system schematic. The primary (rear) brake circuit is shown in green
and the secondary (front) brake circuit is shown in orange.
PP-DC
™
Park
Control Valve
Tractor/Trailer Parking and Emergency Systems