3
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
™
air dryer system or a dryer reservoir 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, 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.
REMOVING
1. Secure the vehicle on a level surface by means other
than the brakes.
2. Drain all reservoirs to 0 p.s.i. (0 kPa) air pressure.
3. Identify, mark and remove the air lines from the TW-N
™
valve.
4. Remove the TW-N
™
valve from the vehicle.
DISASSEMBLY
1. Before disassembly, move the TW-N
™
valve lever to the
air delivery position and note or mark the position of the
lever relative to the valve body. NOTE: The TW-N
™
valve
is in the air delivery position when the plunger is closest
to the mounting surface of the body. Confirm that the
TW-N
™
valve is in the air delivery position by applying air
to the supply port and noting that it exits the delivery
port.
2. Using a drift punch, drive the lever pin out and remove
the lever.
3. Remove the plunger and plunger return spring.
4. Remove both the large and small diameter o-rings from
the plunger.
CLEANING AND INSPECTION
1. Clean the valve body, plunger return spring and plunger
in a mild solvent such as mineral spirits and dry
thoroughly.
2. Inspect the valve body bore and piston for scratches,
nicks, cracks and distortion. If noted, the entire TW-N
™
valve must be replaced.
3. Inspect the return spring for distortion and corrosion. If
noted, the entire TW-N
™
valve must be replaced.
ASSEMBLY
Prior to assembly lubricate the valve body bore, plunger and
o-rings with Bendix silicone lubricant Pc. Nos. 291126.
1. Install large and small diameter o-rings on plunger.
2. Install plunger return spring in body and install plunger.
3. Note the lever position marked during disassembly. Care
should be exercised as lever can be installed in either
position. (Lever position is dictated by function marked
on dial or dash.) Place lever in body and gently depress
the lever and plunger until the lever pin holes in the
body and the lever are aligned.
4. Install the lever pin and press into position. It may be
necessary to hold the lever to guide the pin into the
body hole opposite the press. The lever pin should be
flush with the body on one side.
INSTALLING
1. Install the TW-N
™
valve on the vehicle.
2. Connect the air lines to the TW-N
™
valve according to
the markings made during “Removal”. IMPORTANT:
Fittings installed in the supply and delivery ports of the
TW-N
™
valve should not be torqued to greater than 8 ft.
lbs. (10.85 N.M).
3. Before placing the vehicle in service, perform the
“Operation and Leakage Tests”.
BW1444 © 2004 Bendix Commercial Vehicle Systems LLC. All rights reserved. 3/2004 Printed in U.S.A.
