3
4. If the QR-N
™
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
using a genuine Bendix maintenance kit.
5. Use only genuine Bendix replacement parts and
components.
A. Only components, devices, mounting and attaching
hardware specifi cally designed should be used.
B. Replacement hardware, tubing, hose, fi ttings, etc.
should be of equivalent size, type, length, and
strength as the original equipment.
C. Make certain that when replacing tubing or hose, all
supports, clamps or suspending devices that were
originally installed by the vehicle manufacturer are
reinstalled.
6. Devices with stripped 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 fi ttings 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" fl ange 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 load should be anticipated and can be
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. Clean the upper and lower body 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. It is recommended that the diaphragm and sealing ring
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. If applicable, inspect the diaphragm follower and spring
for any corrosion and pitting, replace if necessary.
ASSEMBLY
1. Place the supply port of the upper body down on a clean,
level work surface. Install the fl at circular diaphragm in
the upper body making certain it is CENTERED.
2. If applicable, install and center the diaphragm follower
with its fl at fl ange 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
that the diaphragm remains centered in the upper body
and the sealing ring enters its groove in the upper
body.
4. Install the four 1/4" fl ange 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 fi ttings 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 fi nger tight for each.)
3. Connect the air lines to the QR-N
™
valve as identifi ed
in Step 4 of "Removing the QR-N
™
Valve".
4. Perform the “Operating and Leakage Tests” before
placing the vehicle in service.
