Bendix® QR-1C® Double Check and Quick Release Valve
SD-03-904
Mounting Holes
Cap Nut
Supply
Port(1)
Delivery (2)
FIGURE A
DESCRIPTION
The Bendix® QR-1C® is a dual function valve. The valve’s
primary function is to serve the emergency side of a spring
brake actuator as a quick release valve. In addition, it
functions as an anti-compound device. The double check
valve prevents a service and emergency brake application
from occurring simultaneously.
The QR-1C® valve is generally mounted on the axle and
serves two spring brake actuators. The air connections to
the QR-1C® valve are as follows:
1. QR-1C® valve delivery port (2) connected to emergency
port of spring brake.
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2. QR-1C
of brake valve or relay valve. NOTE: If relay valve
is installed on vehicle, it should be connected to the
delivery side (not service or signal side).
3. QR-1C
park control valve.
valve balance port (1) connected to delivery
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valve supply port (1) connected to delivery of
Double Check
Diaphragm
Balance Port(1)
Sealing Ring
Sealing
Delivery
Cover
Exhaust
Quick Release
Diaphragm
In its standard confi guration the valve is designed to deliver
within 1 psi of control pressure. However, for special
applications the valve is available with greater differential
pressure or zero hysteresis. QR-1C® valves also come
with optional noise reducing foam crosses or silencers.
Some QR-1C® valves can also come with biased double
check valves. These double check valves contain a beaded
seat cap nut (Figure B). The bias design minimizes low
differential leakage.
Beaded
(Biased) Seat
Non-Beaded
Body
Ring
FIGURE B
Identifi cation
Mark
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OPERATION
SPRING BRAKES RELEASED
When the spring brakes are released, air from the park
control valve fl ows through the QR-1C® valve, causing
the double check valve and quick release diaphragms to
fl ex and seal the balance and exhaust ports. Air fl ows into
the emergency port of the spring brakes from the QR-1C
valve delivery ports.
SPRING BRAKES APPLIED
When the spring brakes are applied, supply line air pressure
to the valve is exhausted through the park control valve.
As air pressure is removed from one side of the double
check valve and quick release diaphragms, they fl ex in
the opposite direction opening the balance and exhaust
ports. Spring brake emergency pressure is released at
the exhaust port of the valve while the small amount of air
trapped between the two diaphragms is released through
the relay valve or brake valve exhaust.
ANTI-COMPOUNDING
When a service brake application is made with the spring
brakes applied, service air enters the balance port and
fl ows through the valve into the emergency ports of the
spring brakes. This prevents the compounding of a service
and spring brake application. Service air passing through
the valve flexes the double check and quick release
diaphragms, sealing the supply and exhaust ports. When
the service application is released, air is exhausted from
the spring brakes.
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DISASSEMBLY
Mark the relationship of the body and cover before
disassembly.
1. Remove cap nut.
2. Remove sealing ring from cap nut.
3. Remove double check valve diaphragm.
4. Remove four Phillips head screws.
5. Separate the body and cover and remove the sealing
ring and quick release diaphragm.
CLEANING AND INSPECTION
Clean all metal parts in mineral spirits. Wipe all rubber
parts clean. It is recommended that all rubber parts and
any other part showing signs of wear or deterioration be
replaced with genuine Bendix® parts.
ASSEMBLY
1. Install sealing ring on cap nut.
2. Install double check valve diaphragm in body.
3. Install cap nut and torque to 150-400 inch pounds.
4. Install sealing ring in valve body.
5. Install the quick release diaphragm in the cover.
6. Install the cover and diaphragm on body, aligning the
marks made during disassembly . Secure together using
the four Phillips head screws and torque to 30-60 inch
pounds.
7. Re-install the QR-1C® valve and before putting the
vehicle in service, perform the “Operation and Leakage
Tests.”
PREVENTIVE MAINTENANCE
Important: Review the Bendix Warranty Policy before
performing 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 valuable guide in determining the best maintenance
interval for air brake system components. At a minimum, the
QR-1C® valve should be inspected every 12 months or
3600 operating hours, whichever comes fi rst, for proper
operation. Should the QR-1C® valve not meet the elements
of the operational tests noted in this document, further
investigation and service of the valve may be required.
REMOVAL
1. Block vehicle wheels and/or hold vehicle by means
other than air brakes.
2. Drain all air brake system reservoirs.
3. Identify and disconnect air lines from valve.
4. Remove mounting bolts, then valve.
OPERATING AND LEAKAGE TESTS
Before performing these tests, park the vehicle on a level
surface and hold the vehicle by means other than the
brakes.
1. With the park control valve in the released position,
note that the spring brakes are released.
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2. Remove the air line connected to the QR-1C
balance port and apply a soap solution to the exhaust
and balance port. A 1" bubble in 5 seconds is permissible
at either location.
3. Reconnect the QR-1C
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valve balance line; and using
the park control valve, park the vehicle. NOTE: A prompt
application of the spring brakes with an exhaust of air
at the QR-1C® valve exhaust port.
4. Remove the air line connected to the supply port of the
QR-1C® valve. With a service brake application hold
applied, apply a soap solution to the supply port and
around the seam between the body and cover. A 1"
bubble in 5 seconds is permissible at the supply port.
No leakage is permitted between the body and cover.
valve
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5. Reconnect the supply port air line. If the valve does
not function as described, or if leakage is excessive,
it is recommended that it be replaced with a new or
remanufactured unit, or repaired with genuine Bendix®
parts.
INSTALLATION
Mount valve with exhaust port pointing down; securely
tighten mounting bolts. Reconnect air lines as identifi ed
during removal.
GENERAL SAFETY GUIDELINES
WARNING! PLEASE READ AND FOLLOW
THESE INSTRUCTIONS TO A VOID PERSONAL
INJURY OR DEATH:
When working on or around a vehicle, the following
general precautions should be observed at all times.
1. Park the vehicle on a level surface, apply the
parking brakes, and always block the wheels.
Always wear safety glasses.
2. Stop the engine and remove 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.
3. 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.
4. 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
an AD-IS
module, be sure to drain the purge reservoir.
5. Following the vehicle manufacturer’s recommended
procedures, deactivate the electrical system in a
manner that safely removes all electrical power
from the vehicle.
6. Never exceed manufacturer’s recommended
pressures.
7. Never connect or disconnect a hose or line
containing pressure; it may whip. Never remove
a component or plug unless you are certain all
system pressure has been depleted.
8. Use only genuine Bendix® replacement parts,
components and kits. Replacement hardware,
tubing, hose, fi ttings, etc. must be of equivalent
size, type and strength as original equipment and
be designed specifi cally for such applications and
systems.
9. 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.
10. Prior to returning the vehicle to service, make
certain all components and systems are restored
to their proper operating condition.
11. 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.
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air dryer system or a dryer reservoir
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BW1585 © 2010 Bendix Commercial Vehicle Systems LLC. All rights reserved. 5/2010 Printed in U.S.A.
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