BENDIX TCH-003-048 User's Manual

Bulletin No: TCH-003-048
Effective Date: 10/4/05
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Flood Damage: Bendix Recommended Procedure for Trailer and
Dolly Control Systems that may have been Submerged.
This Bulletin provides a recommended procedure for the inspection and (where possible) reconditioning of
the air brake control system components on a trailer or dolly that has been submerged in flood waters.
CAUTION: Take all appropriate safety measures when working in conditions where hazardous
waste, etc. may be present, including appropriate eye protection, gloves and masks. See the
General Precautions section at the end of this Bulletin for recommended standard maintenance safety
practices for normal conditions.
Bendix Commercial Vehicle Systems LLC recommends immediate replacement
of all trailer or dolly pneumatic air brake valves that have been submerged in
salt (sea) water to avoid any immediate or future operational issues as a result of
internal corrosion. Due to the extremely corrosive nature of salt water and the inherent
removal of valve lubrication, sudden and premature valve malfunction can result. Vehicle
components recommended to be replaced include air reservoir(s), relay valves, spring
brake valves, ABS relay-modulators and brake actuators. If the air brake components
are being replaced, there is no need to conduct the Air Brake System Inspections below,
instead go to the sections for ABS System inspections and also the “General” heading
for steps in restoring the vehicle to service.
In all other cases where the trailer or components
have been submerged in fresh water, the
recommended steps depend upon what is found
during the following inspections. If the vehicle was
in a coastal area and you are not certain whether
the water submergence was by fresh water or salt
(sea) water, our recommendation is to follow the
guidelines for salt water submergence above. A
separate section in this Bulletin covers inspections
for the ABS system.
While it is not the scope of this Bulletin to address
anything beyond the air brake control system of the
trailer and dolly, as a useful first step, Bendix
Commercial Vehicle Systems LLC recommends that
a thorough power-washing of the trailer and dolly,
including the foundation brakes, will assist the
technician in determining the condition of the vehicle
components. Follow usual chassis re-lubrication
measures (including re-greasing of slack adjusters)
after power-washing.
Since water and contaminants could have passed
into the air brake system through unprotected
gladhands, thoroughly inspect the gladhands and
the supply and control hoses to determine if any liquid
or solid contaminants are present.
If evidence of water or contamination is found
in either control or supply hoses, go to Section
A below.
If there is no obvious evidence of water or
contamination, mark and remove the connectors
at the first valve in the system from the front. Inspect
the valve for water and contaminants. Carefully use
air pressure to blow air through the hoses and watch
for evidence of water or contamination. CAUTION:
Take all necessary precautions for safety of the
technician and others in the work area during
this procedure, including use of appropriate
eye protection.
If evidence of water or contamination is found,
go to Section A below.
Continue to inspect all the valves in the air brake
system, removing one service and control hose from
each of the valves and inspect to determine if there
is evidence of water or contamination. If evidence
of water or contamination is found, follow the
instructions under Section A.
continued over
Bulletin No: TCH-003-048
Effective Date: 10/4/05
If no evidence of water or contamination is found in
any of the valves or hoses, follow the braking system
inspections shown in Section B.
Section A. Trailer or dolly air brake systems
with evidence of water or contamination
Once water or contamination has entered into any
of the air brake components (for example through
the exhaust valves, etc.), removal of all the water or
contamination is not possible without total
disassembly of the components. Therefore Bendix
recommends that all pneumatic air brake
components be replaced (including the air
reservoir(s), relay valves, spring brake valves, ABS
relay-modulators, and brake actuators). This action
is necessary to avoid any immediate or future
operational issues as a result of internal corrosion
and water migration. Replace any trailer system air
dryer present. Also, for ABS system checks, see the
“ABS Systems” section below.
See “General” subheading below for hose cleaning/
replacement recommendations.
Section B. Trailer or dolly air brake system
with no evidence of water/contaminants
Trailer/Dollies with only limited exterior exposure to
fresh water can be returned to service after having
their air brake system thoroughly tested. Include
checks to verify that the parking and emergency
brakes apply and release and that the reservoirs
charge with minimal leakage (See General section
at the end of this Bulletin for details of a leakage
test). Also check that the application and release of
the trailer and dolly service brakes occurs with no
perceptible lag through the full range of normal
service brake applications. Replace any nonfunctioning valves.
For ABS system checks, see “ABS Systems” section
below. Vehicles with normally-functioning air brake
systems can be returned to service. Be sure that
towing vehicles have regularly-serviced air dryers to
aid in removing any residual moisture from the trailer
or dolly system.
In addition, all reservoirs should be pressurized and
then slowly drained using their drain valves to remove
any contents. After 30 days retest the vehicle.
Bendix recommends that trailers and dollies
that do not show any internal evidence of water
or contamination be retested 30 days after the
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vehicle has been returned to service. Bendix
recommends that the vehicle be re-tested for
operation, leakage, and contamination, and that
a diagnostic check of the ABS system be carried
out (see below). Use diagnostic software (e.g.
Bendix® ACom5™ PC-Diagnostic Software) to look for
any present or intermittent trouble codes stored in
the ABS ECU. Any air brake components found
inoperative should be replaced.
ABS systems on trailers and dollies are comprised
of an ABS wire harness, wheel speed sensors, and
an Electronic Control Unit (ECU) — in many cases
with an attached relay/modulator valve assembly
(see above for air brake valve inspections).
ABS System Physical Inspection. Inspect ABS
harnesses for damage, cuts, chafing, etc. and
replace as necessary (Bendix does not recommend
repairing or splicing harnesses).
Since the action of floodwaters and power-washing
may move the ABS wheel speed sensors from their
normal position close to the exciter (tone) ring, push
(by hand) each of the wheel speed sensors until they
contact the exciter ring. Normal wheel bearing play
will adjust the sensor position when the wheel turns.
When replacing ABS wheel speed sensors, either
because of damage, or as a result of electronic
diagnostic checks (see below), follow carefully the
lubrication and re-installation instructions in the
instruction sheet that is included with the replacement
sensor (or, if available, you may use BW-120-A).
Whenever a wheel speed sensor is removed from
its mounting block, Bendix recommends that the
sensor clip be replaced.
ABS System Electronic Inspection.
Unless damaged, Bendix ® ABS trailer or dollymounted ECUs are normally “weatherproof” and are
not affected by water or most types of contamination.
Attach the trailer or dolly to a towing vehicle and
power up the system. Note any ABS indicator lamp
diagnostic codes. As necessary, use diagnostic
software (e.g. Bendix ® ACom5 ™ PC-Diagnostic
Software) to look for any present or intermittent
trouble code history stored in the ECU. Replace
components as necessary.
Bendix recommends that standard operator pre-trip
inspections to ensure proper air brake system
operation be rigorously performed for all vehicles
potentially impacted by flood conditions.
Bulletin No: TCH-003-048
Effective Date: 10/4/05
When replacing pneumatic system components that
have been subjected to flood conditions, Bendix
recommends that all contaminated air hoses be
disconnected and flushed with clean water and blown
out with air pressure to remove contaminants.
CAUTION: Take all necessary precautions for
safety of the technician and others in the work
area during this procedure, including eye
If the contamination cannot be removed from an air
line in this manner, replace the air line using SAE
approved materials.
Air Brake System and Accessory Leakage Test
Park the vehicle on level ground and chock the
wheels. Build system pressure to governor cut-out
and allow the pressure to stabilize for one minute.
Step 1: Observe the dash gauges for two additional
minutes without the service brakes applied.
Step 2: Apply the service brakes and allow the
General Precautions. WARNING! PLEASE READ
When working on or around a vehicle, the following
general precautions should be observed at all times.
Park the vehicle on a level surface, apply the
parking brakes, and always block the wheels.
Always wear safety glasses.
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.
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
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.
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pressure to stabilize. Continue holding for two
minutes (you may use a block of wood to hold the
pedal in position.) Observe the dash gauges.
If you see any noticeable decrease of the dash air
gauge readings (i.e. more than 4 psi, plus two psi for
each additional trailer) during either two minute test,
repair the leaks and repeat this test to confirm that
they have been repaired.
For more information, see Bendix air leakage video
BW2322(DVD), BW2324(VHS), or BW2327(CD).
Bendix Technical Assistance Team
For direct telephone technical support, call the Bendix
technical assistance team at:
1-800-AIR-BRAKE (1-800-247-2725-2-1),
Monday through Friday, 8:00 A.M. to 6:00 P.M. EST,
and follow the instructions in the recorded message.
Or, you may e-mail the Bendix technical assistance
team at:
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
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
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.
© 2005 Bendix Commercial Vehicle Systems LLC 10/05. All Rights Reserved. Printed in U.S.A.