BENDIX PP-7 TRAILER SUPPLY VALVE

1
®
Bendix
®
PP-7
™
Trailer Supply Valve
SD-03-3617
EXHAUST
LOCK
WASHER
1/8 P.T.
SUPPLY
NUT & THREAD
CAP SCREW
(18) PLUNGER
RETURN
SPRING
SPIROL
PIN (1)
(12) O-RING
BUTTON (2)
THIN NUT
(17) PLUNGER
HEX LOCK NUT (15)
FUNCTION AND DESCRIPTION
The PP-7
™
trailer supply valve provides in cab control for the
tractor protection system and functions in conjunction with
the park control valve. It is responsible for synchronizing the
tractor and trailer parking and emergency brakes.
It is essentially a combination of two non-modulating, on-
off control valves in a single, compact package.
Each of the four pipe tapped ports of the PP-7
™
valve are
identified with cast in, raised letters. The supply and control
ports have 1/8 inch N.P.T.F. dry seal pipe threads while the
delivery and exhaust ports have 1/4 inch N.P.T.F. dry seal
pipe threads.
GENERAL OPERATION
The PP-7 trailer supply valve is a panel mounted, push-pull
operated control valve. The button of the PP-7
™
valve must
be manually depressed, but will automatically pop out and
exhaust if supply air is below 40 p.s.i. Fifty p.s.i. or greater
supply air pressure is required for the button to remain in
LOCK
WASHER
CAP SCREW
(13) INLET &
EXHAUST
VALVE
1/4 P.T. DELIVERY
(9) O-RING
1/8 P.T. CONTROL
O-RING (19)
BODY
INLET & EXHAUST
(16) VALVE
RETAINING RING (10)
SEALING RING (3)
O-RING RETAINER (11)
INLET & EXHAUST (14)
VALVE SPRING
SPRING (7)
LOWER BODY
PISTON (6)
O-RING (8)
O-RING (5)
END PLATE (4)
FIGURE 1 - EXTERIOR
FIGURE 2 - SECTIONAL

BENDIX PP-7 TRAILER SUPPLY VALVE Specifications

General

Brand	BENDIX
Model	PP-7 TRAILER SUPPLY VALVE
Category	Control Unit
Language	English

Summary

FUNCTION AND DESCRIPTION

Overview of PP-7 Trailer Supply Valve

GENERAL OPERATION

Push-Pull Operation

OPERATIONAL MODES

Operation Below 50 PSI

With <50 PSI, the button is out; park control valve does not deliver air to the control port.

Operation Above 50 PSI

With >50 PSI, button can be depressed and stay in; park control valve delivers pressure to control port.

EMERGENCY OPERATIONS

Manual Emergency

Pulling the button closes plunger inlet and unseats exhaust valve for disconnection.

Automatic Emergency

SPECIFIC OPERATIONAL SCENARIOS

Automatic Exhaust (No Override)

Park Application

OPERATING AND LEAKAGE CHECKS

Leakage Testing

Pressure Checks

SAFETY WARNINGS

General Vehicle Safety

Park on level surface, apply parking brakes, block wheels, wear safety glasses.

Engine and System Safety

Stop engine, remove key, drain system pressure, and avoid working on pressurized lines.

Component Handling and Repair

Use genuine parts, do not attempt unauthorized repairs, and ensure proper system condition.