BENDIX QR-N QUICK RELEASE VALVE User manual

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Bendix®QR-N™Quick Release Valve
SD-03-905
MOUNTING HOLE (2) SUPPLY PORT
FIGURE 1
EXHAUST PORT
DELIVERY
PORT
DESCRIPTION
ThefunctionoftheBendix®QR-N™quickreleasevalveisto
“speedup”the exhaust of air fromtheactuators it serves. It
is generally mounted on the vehicle axle midway between
the two actuators connected to it.
In the standard (Refer to Figure 1) QR-N™valve a flat
circular diaphragm is installed between the nonmetallic
upper body and stamped steel lower body.An o-ring seals
thetwobodyhalveswhich are held together using four1/4"
machine screws and flange nuts.
In its standard configuration the QR-N™valve is supplied
with a 1 psi (6.9 kPa) maximum differential. For example
withsupply pressure at 10 psi(68.9 kPa) delivery pressure
is 9 psi (61.8 kPa). Higher differential pressures are
available for special applications and are obtained by the
additionofa spring and diaphragm follower tothestandard
QR-N™valve (Refer to Insert A).
Variouspipethreadsizesareavailableforthesinglesupply
port and two delivery ports of the QR-N™valve. QR-N™
valve mounting is accomplished via two 11/32" diameter
holes on 1-1/2" centers.
OPERATION
With no air pressure applied to the QR-N™valve (Refer
to Figure 1), the diaphragm is slightly flexed by the upper
and lower body. In this condition the center portion of the
diaphragmrestson the exhaust port in the lower body while
the outer edge and opposite side of the diaphragm rests
against the sealing lip of the upper body.
APPLY
Airentering the supply port of the QR-N™valve causesthe
center portion of the diaphragm to seal the exhaust port.
Simultaneously, the outer edge of the diaphragm moves
away from the sealing lip of the upper body allowing air to
flow from the supply port out the delivery ports.
BALANCE
When air pressure on both sides of the diaphragm
is approximately equal (1 psi differential), the natural
resiliency of the diaphragm material causes the outer
edge of the diaphragm to move into contact with the upper
bodysealinglip.The QR-N™valve exhaustremainssealed
because air pressure bears against the center portion of
the diaphragm from one side only.
UPPER BODY
DELIVERY
PORT
SEALING RING LOCKWASHER
CAP SCREW
SPRING FOLLOWER
DIFFERENTIALSPRING
LOWER
BODY
INSERTA
DIAPHRAGM

2
RELEASE
When air pressure is reduced or removed from the QR-N™
valve supply port, the air pressure on the delivery side
of the diaphragm is greater than that on the supply side.
The higher delivery side pressure holds the outer edge of
the diaphragm against the upper body sealing lip while
simultaneously moving the center portion away from the
exhaust port. Air from the delivery ports flows out the
exhaust. When air pressure on the delivery side of the
diaphragm equals the pressure on the supply side, the
center portion of the diaphragm moves into contact with
the exhaust port.
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
intervalforairbrake system components.Ata minimum,
the QR-N™valve should be inspected every 12 months
or 3600 operating hours, whichever comes first, for
proper operation. Should the QR-N™valve not meet the
elementsoftheoperationaltestsnotedinthisdocument,
further investigation and service of the valve may be
required.
GENERAL SAFETY GUIDELINES
WARNING! PLEASE READ AND FOLLOW
THESEINSTRUCTIONSTOAVOIDPERSONAL
INJURY OR DEATH:
When working on or around a vehicle, the following
general precautions should be observed at all times.
1. Park thevehicle on alevel surface, applythe parking
brakes, and always block the wheels. Always wear
safety glasses.
2. Stop the engine and remove ignition key when
working under oraround 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 certainto drain theair pressure from
all reservoirs before beginning ANY work on the
vehicle. If the vehicle is equipped with an AD-IS®
air dryer system or a dryer reservoir module, be
sure to drain the purge reservoir.
5. Following thevehicle 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 orplug unless youare certain allsystem
pressure has been depleted.
8. Use only genuine Bendix®replacement parts,
components and kits. Replacement hardware,
tubing, hose, fittings, etc. must be of equivalent
size, type and strength as original equipment and
be designed specifically 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 specifically 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 Antilock 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.
OPERATING AND LEAKAGE TESTS
1. Apply 100 psi (689 kPa) air pressure to the supply port
oftheQR-N™valve and note thatthedevice connected
to the QR-N™valve responds promptly.
2. With 100 psi (689 kPa) air pressure applied to the
QR-N™valveSUPPLYport applya soap solution tothe
exhaust port and around the junction of the upper and
lower body halves.
A.No leakage is permitted between the body halves.
B.Leakage of greater than a 1" (25.4 mm) bubble in 3
seconds at the exhaust port is unacceptable.
3. Release the air pressure at the supply port and note
thatthedeviceconnectedtotheQR-N™valveresponds
promptly and returns to a zero air pressure condition.

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4. If the QR-N™valve does not function as described or
if leakage is excessive, it is recommended that it be
replacedwith a new or remanufacturedunit or repaired
using a genuine Bendix maintenance kit.
5. Use only genuine Bendix replacement parts and
components.
A. Onlycomponents,devices,mounting and attaching
hardware specifically designed should be used.
B. Replacement hardware, tubing, hose, fittings, etc.
should be of equivalent size, type, length, and
strength as the original equipment.
C. Makecertainthat when replacing tubing or hose,all
supports, clamps or suspending devices that were
originally installed by the vehicle manufacturer are
reinstalled.
6. Deviceswithstripped threads or damaged parts should
be replaced. Repairs requiring machining should not
be attempted.
REMOVING THE QR-N™VALVE
1. Park the vehicle on a level surface. Block the wheels
and/or hold the vehicle by means other than the air
brakes.
2. Drain all air brake system reservoirs.
3. Identify, mark and disconnect all air lines from the
valve.
4. Remove all tubing or hose fittings from the valve.
5. Remove the valve mounting hardware and the valve.
DISASSEMBLY
The following disassembly procedure is provided as a
reference. Before disassembling the QR-N™valve, a
Bendix maintenance kit or genuine replacement parts
should be available.
1. Remove the four 1/4" flange nuts and bolts that secure
the upper and lower body halves. NOTE: Before
removing the last two nuts and bolts completely, check
the opening between the body halves to determine if
the QR-N™valve has a differential spring installed. If
so,a light spring loadshouldbe anticipated and canbe
easily controlled by manually holding the body halves
together.
2. Separate the body halves and remove the diaphragm
(and diaphragm follower and spring if so equipped).
3. Remove the sealing ring between the body halves.
CLEANING & INSPECTION
1. Cleantheupperandlowerbody halves; also diaphragm
follower and spring (if applicable) in mineral spirits. Do
not immerse nonmetallic components for a prolonged
period of time (no more than 10 minutes). Dry all parts
thoroughly.
2. Itis recommended that the diaphragm and sealingring
be replaced after disassembly.
3. Inspect the upper body for galled threads and cracks.
If found, the entire QR-N™valve should be replaced.
4. Inspect the interior valve portion of the lower body for
heavy corrosion and pitting. If found, replace the entire
QR-N™valve assembly.
5. Ifapplicable,inspect the diaphragm follower and spring
for any corrosion and pitting, replace if necessary.
ASSEMBLY
1. Placethesupplyportoftheupperbodydownonaclean,
level work surface. Install the flat circular diaphragm in
the upper body making certain it is CENTERED.
2. If applicable, install and center the diaphragm follower
with its flat flange side against the diaphragm. Install
the spring on the diaphragm follower.
3. Install the sealing ring on the lower body and carefully
install the lower body on the upper body. Make certain
thatthediaphragm remains centered in theupperbody
and the sealing ring enters its groove in the upper
body.
4. Install the four 1/4" flange nuts and bolts and torque to
60 inch pounds (6.78 N.M).
INSTALLING THE QR-N™VALVE
1. Mount the QR-N™valve on the vehicle.
2. Install the tubing or hose fittings in the upper body of
the QR-N™valve. If a thread sealant is used, make
certain that this material will not enter the valve during
use. IMPORTANT: WHEN INSTALLING FITTINGS,
DO NOT TORQUE BEYOND THE FOLLOWING OR
DAMAGE TO THE UPPER BODY MAY RESULT:
12 ft. lbs. (16.3 N.M) for the supply port
10 ft. lbs. (13.6 N.M) for the delivery ports
(or 2-1/2 turns beyond finger tight for each.)
3. Connect the air lines to the QR-N™valve as identified
in Step 4 of "Removing the QR-N™Valve".
4. Perform the “Operating and Leakage Tests” before
placing the vehicle in service.

4BW1586 © 2007 Bendix Commercial Vehicle Systems LLC All rights reserved. 9/2007 Printed in U.S.A.