BENDIX PR-3 User manual

1
Bendix®PR-3™and PR-4™Valve Maintenance Kit
Kit Contents
Item No. Description Qty.
1 Piston Assembly with O-ring 1
2 O-ring 1
3 Spring 1
4 Check Valve 1
5 Tube of Lubricant 1
6 Retaining Ring 1
Bendix®PR-3™Reservoir Control Valve Bendix®PR-4™Pressure Protection Valve
11
2
3
4
Figure 1 Figure 2
5
6
This kit will service both the Bendix®PR-3™Reservoir
Control Valve and the Bendix®PR-4™Pressure Protection
Valve. The principle di󰀨erence between the two (2) valves
is the inclusion of the check valve components in the PR-3
reservoir control valve. See Figures 1 and 2. When this kit
is used for the repair of a PR-4 pressure protection valve,
pressure protection valve (Figure 2) items 2, 3, and 4 will
not be used.
This kit consists of the items which are keyed to the sectional
views of both valves, by the circled key numbers.
Spring(s)
Spring Retainer
Machine
Screws
Machine
Screws
Body
Body
O-ring
Retainer

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GENERAL SAFETY GUIDELINES
WARNING! PLEASE READ AND FOLLOW THESE INSTRUCTIONS
TO AVOID PERSONAL INJURY OR DEATH:
When working on or around a vehicle, the following guidelines should be observed AT ALL TIMES:
▲Park the vehicle on a level surface, apply the
parking brakes, and always block the wheels.
Always wear personal protection equipment.
▲Stop the engine and remove the ignition key
when working under or around the vehicle.
When working in the engine compartment,
the engine should be shut off and the ignition
key should be removed. Where circumstances
require that the engine be in operation, EXTREME
CAUTION should be used to prevent personal
injury resulting from contact with moving,
rotating, leaking, heated, or electrically charged
components.
▲Do not attempt to install, remove, disassemble,
or assemble a component until you have read,
and thoroughly understand, the recommended
procedures. Use only the proper tools and
observe all precautions pertaining to use of those
tools.
▲If the work is being performed on the vehicle’s
air brake system, or any auxiliary pressurized air
systems, make certain to drain the air pressure
from all reservoirs before beginning ANY work
on the vehicle. If the vehicle is equipped with
a Bendix®AD-IS®air dryer system, a Bendix®
DRM™dryer reservoir module, a Bendix® AD-9si®,
AD-HF®, or AD-HFi™air dryer, be sure to drain the
purge reservoir.
▲Following the vehicle manufacturer’s
recommended procedures, deactivate the
electrical system in a manner that safely removes
all electrical power from the vehicle.
▲Never exceed manufacturer’s recommended
pressures.
▲Never connect or disconnect a hose or line
containing pressure; it may whip and/or cause
hazardous airborne dust and dirt particles. Wear
eye protection. Slowly open connections with
care, and verify that no pressure is present. Never
remove a component or plug unless you are
certain all system pressure has been depleted.
▲Use only genuine Bendix®brand replacement
parts, components, and kits. Replacement
hardware, tubing, hose, fittings, wiring, etc.
must be of equivalent size, type, and strength as
original equipment and be designed specifi cally
for such applications and systems.
▲Components with stripped threads or damaged
parts should be replaced rather than repaired.
Do not attempt repairs requiring machining or
welding unless specifi cally stated and approved
by the vehicle and component manufacturer.
▲Prior to returning the vehicle to service, make
certain all components and systems are restored
to their proper operating condition.
▲For vehicles with Automatic Traction Control
(ATC), the ATC function must be disabled (ATC
indicator lamp should be ON) prior to performing
any vehicle maintenance where one or more
wheels on a drive axle are lifted off the ground
and moving.
▲The power MUST be temporarily disconnected
from the radar sensor whenever any tests USING
A DYNAMOMETER are conducted on a vehicle
equipped with a Bendix® Wingman®system.
▲You should consult the vehicle manufacturer's operating and service manuals, and any related literature,
in conjunction with the Guidelines above.

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REMOVAL
Before removing the valve, park the vehicle and drain the air
system completely, follow the safety guidelines on page 2.
1. To aid in the installation of the valve, mark the air lines
and their respective ports before disconnecting.
2. Remove and retain the mounting hardware.
3. Remove the valve from the vehicle.
DISASSEMBLY
1. Remove the four (4) round head machine screws while
holding the spring retainer to the body. Remove the
spring retainer.
The spring retainer is under a spring load and must
be removed carefully.
2. Remove and retain the spring(s) under the retainer for
reuse.
NOTE: Some Bendix®PR-3™Reservoir Control Valves
and Bendix®PR-4™Pressure Protection Valves have
only one (1) spring and some will have two (2).
3. Remove and discard the piston assembly.
NOTE: This would conclude the disassembly procedure
for a PR-4 pressure protection valve (Figure 2). The
following steps are for the PR-3 reservoir control valve
(Figure 1).
4. Discard the retaining ring.
5. Remove and reuse the o-ring retainer.
6. Remove and discard the o-ring, spring, and check valve.
ASSEMBLY
NOTE: Prior to the assembly of new parts into the valve,
clean the internal passages with a suitable solvent and dry
thoroughly. Grease all o-rings, o-ring grooves, bores, and
pistons using the lubricant supplied with this kit.
1. Install the piston assembly in the valve body.
2. Position the spring(s) on the piston and install the spring
retainer.
3. Secure the spring retainer using the four (4) round head
machine screws. Torque the screws to 20-30 in-lbs
(2.3-3.4 N•m).
This completes the reassembly of the PR-4
pressure protection valve. Proceed to step 4 for the
PR-3 reservoir control valve.
4. Install the spring on the check valve and install in the
valve body.
5. Install the o-ring in the valve body.
6. Install the o-ring retainer taking care that the spring
ts in the protrusion provided on the o-ring retainer
(See Figure 1).
7. Install the retaining ring.
INSTALLATION
1. Clean the air lines connecting to valve.
2. Inspect all lines and/or hoses for damage and replace
as necessary.
3. Install the valve and tighten the mounting bolts.
4. Connect the air lines to the valve.
OPERATING AND LEAKAGE CHECKS
OPERATING CHECKS
1. Provide a pressure gauge and drain the valve at the
supply side and delivery side of the pressure protection
valve being checked.
2. Build up the air system to full pressure and shut o󰀨 the
engine.
3. While watching the gauges on the supply and delivery
sides of the valve, slowly begin to exhaust pressure
from the delivery side. Note that both gauges will show
pressure loss until the closing pressure of the pressure
protection valve is reached.
The pressure protection valve should close within ±5 psi
of the pressure indicated on the valve's label or in the
vehicle handbook. The gauge on the delivery side of the
valve should continue to show loss of pressure while
the gauge on the supply side should stop at the same
pressure as the setting of the valve.
4. (PR-3 reservoir control valve only) Build pressure up
and slowly exhaust air from the supply side of the PR-3
reservoir control valve. The gauge on the delivery side
of the valve should remain at the highest pressure
previously attained.
LEAKAGE CHECKS
1. Build up the air system to full pressure and shut o󰀨 the
engine.
2. Apply a soap solution around the cap of the pressure
protection valve. A one (1) in. (2.54 cm) bubble in three
(3) seconds or longer is acceptable. No leakage is
permissible at the bottom of the PR-3 reservoir control
valve.
3. Drain the air pressure from the delivery side of the
pressure protection valve and disconnect the air line
to it.
4. Apply a soap solution to the delivery port. A one (1)
in. (2.54 cm) bubble in ve (5) seconds or longer is
acceptable.

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