Bendix Commercial Vehicle Systems TRAILER SYSTEM GUARD AIR DRYER 7/04 User Manual

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Bendix® Trailer System-Guard™ Air Dryer

21

CONTROL OUTLET

22

SUPPLY OUTLET

SD-08-2416

3/8 - 16 UNC x .50 Deep

Mounting Holes (4)

11

CONTROL INLET

12

SUPPLY INLET

ALL SUPPLY & CONTROL PORTS 1/4" NPT

FIGURE 1 - TRAILER SYSTEM-GUARD™ AIR DRYER

DESCRIPTION

The Bendix® Trailer System-Guard™ air dryer removes
moisture and contaminates from the trailer air system. It is
not intended to take the place of a dryer normally located
on the power unit. It acts as a buffer to remove moisture
during wet times and gives up water vapor during dry times.
It protects the trailer air brake system when, for short periods
of time, the trailer is pulled by vehicles without an air dryer
or during times when the trailer is disconnected from the
tractor.

The Trailer System-Guard™ air dryer consists of two
desiccant air dryers mounted in a single housing, one to
protect the trailer service system and the other to protect
the trailer supply system.

PREVENTIVE MAINTENANCE
Every 300 operating hours, 8,000 miles, or one (1)

month:

1. Visually inspect for physical damage or wear to the Trailer
System-Guard™ air dryer. This can include, but is not
limited to, chaffed or broken air hoses and or broken or
missing parts.

2. Check mounting bolts for tightness. If loose re-torque
per "Mounting the Trailer System-Guard™ Air Dryer".

Every 900 operating hours or 25,000 miles or every
three (3) months:

Check for moisture in the air brake system by opening
reservoirs, drain cocks, or valves and checking for the
presence of water. If moisture is present the tractor and
trailer should be checked for leaks. If leakage is not
excessive check the tractor air dryer for proper operation.
If defective, the tractor dryer should be repaired, rechecking
trailer reservoirs again after 3 months. If the tractor dryer
operates satisfactorily and the trailer has not been
connected to a tractor without an air dryer and the trailer
glad hands were not open to the atmosphere for some
extended period of time, the trailer dryer should be replaced.

If the trailer has been connected to a tractor without an air
dryer or the trailer has been parked for an extended period
of time, the trailer should be coupled to a tractor with an air
dryer. This will help the trailer air dryer remove moisture
from the trailer. Place the unit back in service and recheck
for moisture after 3 months.

1

WARNING! PLEASE READ AND FOLLOW
THESE INSTRUCTIONS TO AVOID
PERSONAL INJURY OR DEATH:

When working on or around a vehicle, the following
general precautions should be observed at all times.

1. Park the vehicle on a level surface, apply the
parking brakes, and always block the wheels.
Always wear safety glasses.

2. 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,
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 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.

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.

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EXTREME CAUTION should

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Note: The Trailer System-Guard

air dryer is intended to
remove moisture and other contaminants normally found in
the air brake system. Using alcohol, anti-freeze, oil or other
de-icing substances in the brake system can damage the
air dryer and will therefore void the Trailer System-Guard
air dryer warranty .

OPERATION & LEAKAGE TESTS

Build the air system to governor cutout. Shut off the engine.
Using a soap solution, check all lines and fittings leading to
and from the Trailer System-Guard™ air dryer for leakage
and integrity . Repair any excessive leaks - exceeding a 1"
bubble in 5 seconds-before restoring vehicle to service.

OPERATION: GENERAL

The trailer dryer works as a buffer , removing moisture during
exposure to wet air (trailer hooked to a tractor without an air
dryer, or trailer is parked for extended periods with open
glad hands) and giving up water vapor when reconnected to
a tractor equipped with an air dryer. The Trailer System­Guard™ air dryer depends on dry tractor air to remove water
vapor from the desiccant collected during wet times.

TRAILER SYSTEM-GUARD™ AIR DRYER
REMOVAL

This removal process is presented for the replacement of
the Trailer System-Guard™ air dryer .

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1. Identify and disconnect the four air hoses from the Trailer

System-Guard™ air dryer.

2. Remove the locknuts, washers and grommets that secure

the Trailer System-Guard™ air dryer and remove it from
the vehicle.

REPLACING OR RETROFITTING THE TRAILER

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SYSTEM-GUARD

AIR DRYER: GENERAL

The following instructions are presented for reference
purposes only , since Bendix aftermarket replacement Trailer
System-Guard™ air dryers are packaged with the most up­to-date installation instructions. The instructions packaged
with the Trailer System-Guard™ air dryers should be followed
in lieu of those presented here.

MOUNTING THE TRAILER

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SYSTEM-GUARD

1. After positioning the Trailer System-Guard™ air dryer

according to the location requirements, mark the position
of the predrilled mounting holes on the selected location.
A template for the mounting pattern is included on page

4. Note: Only three of the four mounting holes

must be used for securing the air dryer to the frame
rail. Securing the air dryer at all four mounting holes

can lead to damage and eventual failure of the air dryer.
Any three of the four mounting holes can be used for
installation. Selection is at the discretion of the installer .

If mounting the dryer on a trailer cross member center

the template to maximize clearance and facilitate
installation. Note: Check the vehicle manual before
drilling the selected location.

AIR DRYER

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