WABCO IR-2 Service manual

TP-0357
Revised 06-19
Technical BulletinTechnical Bulletin
WABCO Inversion
Relay Valve (IR-2)
TP-0357Revised 06-191 Technical Bulletin
Hazard Alert Messages
Read and observe all Warning and Caution hazard alert messages in
this publication. They provide information that can help prevent
serious personal injury, damage to components, or both.
WARNING
To prevent serious eye injury, always wear safe eye protection
when you perform vehicle maintenance or service.
Park the vehicle on a level surface. Block the wheels to
prevent the vehicle from moving. Support the vehicle with
safety stands. Do not work under a vehicle supported only by
jacks. Jacks can slip and fall over. Serious personal injury and
damage to components can result.
Release all air from the air systems before you remove any
components. Pressurized air can cause serious personal
injury.
Do not attempt to open or disassemble the inversion relay
valve. This valve has an internal spring that may be damaged
by opening the valve. In addition, internal spring forces may
cause serious personal injury.
Overview
Access Product and Service Information
For additional information about WABCO’s inversion relay valve,
please contact the WABCO Customer Care Center at 855-228-
3203. Literature covering the complete WABCO product line is
posted on our website, www.wabco-na.com.
Inversion Relay Valve (IR-2)
The inversion relay valve (IR-2) combines the functions of two air
brake system valves:
앫A relay valve
앫An inversion valve with anti-compounding protection
Under normal conditions, the IR-2 responds to a control signal from
a dash-mounted parking brake control valve to supply or exhaust air
from the spring brake chambers, thereby applying the spring
brakes. In the event of a primary air system failure, the IR-2 makes
a modulated application of the spring brakes by means of the foot
valve. A typical IR-2 valve installation is shown in Figure 1.

TP-0357
Revised 06-19 (16579)
Page 2 Copyright WABCO, Inc. 2019 Printed in the USA
Figure 1
Installation
Guidelines
NOTE: If you are installing the inversion relay valve on an existing
installation, you must first remove the old valve. Refer to the valve
replacement procedure in this bulletin for instructions.
1. Mount the valve.
앫Refer to the vehicle manufacturer’s specifications for
specific mounting requirements.
앫Select a flat mounting surface. The mounting surface must
be within 0.010-inch (0.25 mm) of flat.
앫For best timing results, mount the valve near the spring
brakes it will serve.
앫Mount the valve with the exhaust port facing down within
30°of vertical.
앫Use 8 mm mounting hardware to attach the valve to the
mounting surface. Tighten to 15 ±2 lb-ft (20 ±3 N폷m).
Figure 2. @
Figure 2
2. Connect the air lines as indicated in Table A. Valve ports are
identified in Figure 3.
앫Make sure all unused supply and delivery ports are
plugged.
앫Look at the air line installation to make sure all air lines are
correctly installed and that all connections are secure.
Figure 1
4003018b
ACC
PURGE
TANK
WET
TANK
PRIMARY
RESERVOIR
SECONDARY
RESERVOIR
AIR
FROM
INLET
FILTER
SUPPLY LINE
PARKING BRAKE
CONTROL LINE
Figure 2
EXHAUST 4003006a
PRODUCT
IDENTIFICATION
TAG

TP-0357
(16579) Revised 06-19
Printed in the USA Copyright WABCO, Inc. 2019 Page 3
Figure 3
Table A: IR-2 Valve Port Identification
Troubleshooting
Function Tests
Non-Failure Mode
When the vehicle’s primary air system is functioning correctly, the
IR-2 valve passes reservoir air to the spring brake chambers as
directed by the park brake valve. To test this operation:
1. Park the vehicle and apply the parking brakes. Place blocks
under the tires to prevent the vehicle from moving.
2. Follow standard shop procedures to install a test gauge in the
delivery line of the valve or at the spring brake chamber.
3. Fully charge the air brake system to 105-130 psi
(724-896 kPa).
4. Release the parking brakes by pushing in the dash-mounted
park brake knob.
5. Check the pressure reading. The test gauge pressure reading
should be 90-105 psi (621-724 kPa).
6. Apply the parking brakes by pulling out the dash-mounted park
brake knob. The IR-2 will exhaust all air in the spring brake
chambers, applying the spring brakes.
If the IR-2 valve does not function as described, check the
installation. Make sure all air lines are correctly routed. Check
the connections for leaks. Make the necessary repairs and
retest. If the problem persists, it may be necessary to replace
the valve. If you have any questions or need additional
assistance, contact the WABCO Customer Care Center at
855-228-3203.
Anti-Compounding
The anti-compounding feature occurs if the service brakes are
applied while the spring brakes are already applied. If this occurs,
the valve will deliver air to the spring brake chambers to release the
spring brakes. To test this function:
1. Park the vehicle. Do not apply the parking brakes. Place blocks
under the tires to prevent the vehicle from moving.
2. Follow standard shop procedures to install a test gauge in the
delivery line of the valve or at the spring brake chamber.
3. Fully charge the air brake system to 105-130 psi
(724-896 kPa).
4. Apply the parking brakes by pulling out the dash-mounted park
brake knob. The IR-2 will exhaust all air in the spring brake
chambers, applying the spring brakes.
5. Make a service brake application by stepping on the foot valve.
This will send reservoir service brake air to the spring brakes.
6. Check the pressure gauge to ensure reservoir pressure
is delivered to the spring brakes, thus indicating the
anti-compounding feature is functional.
If the IR-2 valve does not function as described, check the
installation. Make sure all air lines are correctly routed. Check
the connections for leaks. Make the necessary repairs and
retest. If the problem persists, it may be necessary to replace
the valve. If you have any questions or need additional
assistance, contact the WABCO Customer Care Center at
855-228-3203.
Figure 3
IR-2 Valve Port Assignments
Port Function Typical Line Size
11
12
Reservoir ports
NOTE: If the system includes a
line with blended air from both
tanks through a double check
valve, only one supply line is
connected to the valve. Plug
the remaining port.
1/2" O.D. Tube
21
22
23
24
Delivery ports to spring brake
chambers. If the vehicle has
only two spring brakes, plug
the remaining two ports.
3/8" I.D. Hose
41 Control port to primary
brake circuit
3/8" O.D. Tube or
Push-to-Connect
42 Control port to secondary brake
circuit
3/8" O.D. Tube or
Push-to-Connect
43 Control port to park brake valve 3/8" O.D. Tube or
Push-to-Connect
EXHAUST 4003007a
PORT 43
PORT 41
PORT 24
PORT 12
PORT 22
PORT 23
PORT 21
PORT 42
PORT 11

WABCO North America
1220 Pacific Drive
Auburn Hills, MI 48326 USA
855-228-3203
wabco-na.com
Information contained in this publication was in effect at the time the publication was approved for printing and is subject to
change without notice or liability. WABCO reserves the right to revise the information presented or to discontinue the
production of parts described at any time.
Copyright 2019 TP-0357
WABCO, Inc. Revised 06-19
All Rights Reserved Printed in USA (16579)
Failed Primary System Function
If there is a loss of the primary system air, the valve will respond to
the remaining signal from the secondary brake system. When
secondary pressure increases to 10 psi (69 kPa), the valve will
begin to exhaust air from the spring brake chambers. The spring
brake chambers will be exhausted, fully applying the brakes, before
the secondary service pressure exceeds 75 psi (517 kPa). To test
this function:
1. Place blocks under the tires to prevent the vehicle from
moving.
2. Follow standard shop procedures to install a test gauge in the
delivery line of the valve or at the spring brake chamber.
3. Fully charge the air brake system to 105-130 psi
(724-896 kPa).
4. Drain the air from the primary reservoir.
5. Make a service brake application by stepping on the foot valve.
This exhausts air from the spring brakes.
6. Check the pressure reading. The test gauge should read 0
when the secondary service pressure exceeds 70 psi (483
kPa).
If the IR-2 valve does not function as described, check the
installation. Make sure all air lines are correctly routed. Check
the connections for leaks. Make the necessary repairs and
retest. If the problem persists, it may be necessary to replace
the valve. If you have any questions or need additional
assistance, contact the WABCO Customer Care Center at
855-228-3203.
Air Leakage
Replace the IR-2 valve if leakage exceeds 175 sccm.
NOTE: If accurate measurement equipment is not available, replace
any valve that has a clearly audible air leak.
Leak Test
Perform a leak test to check for air leakage at the air line
connections.
1. Place blocks under the tires to prevent the vehicle from
moving.
2. Drain air from all system tanks.
3. Close the reservoir drain cocks.
4. Start the vehicle. Allow air system pressure to build to
cut-out pressure while the engine idles.
앫If the vehicle is equipped with an air dryer: There will be
a purge or strong blast of air from the air dryer, followed by
a mild flow which will last 10-25 seconds when cut-out
pressure is reached.
5. Apply a soap solution to each connection that contains
pressurized air. Check the connections for soap solution
bubbles.
앫No soap bubbles: Connections are sealed.
앫Soap bubbles: Connections are not sealed.
Connection Seal Repair
To repair connection seals:
1. Drain all reservoirs.
2. Remove the leaking connection.
3. Inspect the connections and ports for damaged threads or
cracks. Replace if necessary.
4. Apply pipe sealant to the pipe thread connection.
NOTE: Repeat the leak test until all connections are sealed.
Ensure that tubes are cut squarely to avoid damage to seals during
insertion into push-to-connect fittings.
Procedures
Valve Replacement
1. Place blocks under the tires to prevent the vehicle from moving
2. Identify, mark and disconnect all air lines from the valve.
3. Remove the mounting hardware that holds the valve to the
vehicle.
4. Remove the old valve from the vehicle.
5. Install the replacement IR-2 valve. Refer to the installation
guidelines in this bulletin for installation instructions.
6. Reconnect the pneumatic lines. Refer to Table A for more
information.
NOTE: All lines must be reinstalled in the same location they
were in before they were removed. Refer to the vehicle
manufacturer’s service manual for complete instructions.
7. Apply 105-130 psi (724-896 kPa) minimum air system
pressure. Test the installation, following the function tests
procedures in this bulletin.