BENDIX TRAILER SYSTEM GUARD AIR DRYER User manual

1
®
DESCRIPTION
The Bendix®Trailer System-Guard™ air dryer removes
moistureandcontaminatesfromthetrailerairsystem. Itis
not intended to take the place of a dryer normally located
on the power unit. It acts as a buffer to remove moisture
duringwettimesandgivesup water vaporduringdry times.
Itprotectsthetrailerairbrakesystemwhen,forshortperiods
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.
PREVENTIVEMAINTENANCE
Every 300 operating hours, 8,000 miles, or one (1)
month:
1. VisuallyinspectforphysicaldamageorweartotheTrailer
System-Guard™air dryer. This can include, but is not
limitedto, chaffed or broken air hoses and or brokenor
missing parts.
FIGURE 1 - TRAILER SYSTEM-GUARD™AIR DRYER
2. Check mounting bolts for tightness. If loose re-torque
per"MountingtheTrailer System-Guard™ AirDryer".
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.
Ifdefective, thetractordryer should berepaired,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
extendedperiodoftime, thetrailer dryershouldbereplaced.
If the trailer has been connected to a tractor without an air
dryerorthetrailerhas been parked for an extended period
oftime,thetrailer should be coupled to a tractor with an air
dryer. This will help the trailer air dryer remove moisture
fromthetrailer. Place the unit backinservice and recheck
for moisture after 3 months.
Bendix®Trailer System-Guard™Air Dryer
SD-08-2416
21
CONTROLOUTLET
22
SUPPLYOUTLET
11
CONTROL INLET
12
SUPPLYINLET
ALLSUPPLY&CONTROLPORTS1/4" NPT
3/8 - 16 UNC x .50 Deep
MountingHoles(4)

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WARNING! PLEASE READ AND FOLLOW
THESE INSTRUCTIONS TO AVOID
PERSONAL INJURYOR 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
enginebe in operation, EXTREME CAUTIONshould
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. Useonly the propertools 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 certainto drain theair pressurefrom
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
recommendedprocedures, deactivatethe 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
lampshould be ON) priorto performing anyvehicle
maintenance where one or more wheels on a drive
axle are lifted off the ground and moving.
Note: The Trailer System-Guard™air dryer is intended to
removemoistureand other contaminantsnormallyfoundin
theair brake system. Usingalcohol,anti-freeze,oil or other
de-icing substances in the brake system can damage the
airdryerandwill therefore void the Trailer System-Guard™
airdryerwarranty.
OPERATION & LEAKAGE TESTS
Buildtheair system togovernorcutout.Shut off the engine.
Usingasoapsolution,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"
bubblein5 seconds-before restoring vehicletoservice.
OPERATION: GENERAL
Thetrailerdryerworks asa buffer,removingmoistureduring
exposuretowet air (trailerhookedtoa tractor withoutanair
dryer, or trailer is parked for extended periods with open
gladhands) andgivingup watervaporwhenreconnectedto
a tractor equipped with an air dryer. The Trailer System-
Guard™airdryer dependsondrytractor airtoremove water
vaporfromthedesiccantcollectedduringwettimes.
TRAILER SYSTEM-GUARD™AIR DRYER
REMOVAL
This removal process is presented for the replacement of
theTrailerSystem-Guard™airdryer.
1. Identifyanddisconnectthe fourairhosesfromtheTrailer
System-Guard™airdryer.
2. Removethelocknuts,washersandgrommetsthatsecure
theTrailerSystem-Guard™airdryer and remove itfrom
thevehicle.
REPLACING OR RETROFITTING THE TRAILER
SYSTEM-GUARD™AIR DRYER: GENERAL
The following instructions are presented for reference
purposesonly,sinceBendixaftermarketreplacementTrailer
System-Guard™air dryers are packaged with the most up-
to-dateinstallationinstructions.Theinstructionspackaged
withtheTrailerSystem-Guard™airdryersshouldbefollowed
inlieuofthosepresentedhere.
MOUNTING THE TRAILER
SYSTEM-GUARD™AIR DRYER
1. After positioning the Trailer System-Guard™air dryer
accordingtothelocationrequirements, marktheposition
ofthepredrilledmounting holeson theselectedlocation.
Atemplatefor the mounting patternisincludedon 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
canlead to damage andeventualfailure of theairdryer.
Any three of the four mounting holes can be used for
installation.Selectionisatthediscretionof 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.

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SUPPLYLINE-CHARGING
SUPPLYLINE-PARKING
CONTROLLINE-BRAKEAPPLICATION
CONTROLLINE-BRAKERELEASE
CONTROL
IN
SUPPLY
IN
CONTROL
OUT
SUPPLY
OUT
CONTROL
IN
SUPPLY
IN
CONTROL
OUT
SUPPLY
OUT
CONTROL
IN
SUPPLY
IN
CONTROL
OUT
SUPPLY
OUT
CONTROL
IN
SUPPLY
IN
CONTROL
OUT
SUPPLY
OUT
FIGURE 2 - TRAILER SYSTEM-GUARD™AIR DRYER OPERATION (VIEWED FROM MOUNTING HOLE SIDE)

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2. Drill the three marked mounting holes into the frame
rail using a 5/8" diameter drill.
3. By hand, install the studs into the three corresponding
holesonthe air dryer. Totighten attachvise gripsto the
studs within 1" of the air dryer and turn 1/4 to 1/2 turns.
Threaddamageonthe studintheareaneartheair dryer
isacceptable. Care shouldbetaken to preventdamage
to the last 1-1/2 inches of the stud at the end opposite
theairdryer end cover.
4. Placearubbergrommet with the flat side toward the air
dryerovereachofthe installed studs.
5. Align and insert the air dryer mounting studs with
grommetsintothe3mountingholesonthevehicle frame
rail. The raised portion or shoulder of the grommets
must fit into the mounting holes drilled into the frame
rail.
6. Installthe remaining grommetsoneach ofthemounting
studswiththeraisedportionorshouldertowardtheframe
rail. Ensurethe shoulderfitsintotheframe railmounting
hole.
7. Using the flat washer and locknut secure the air dryer.
Tightenthelocknutsusinga9/16" wrench turn until the
locknut,washer andoutsidegrommet justmakecontact
(noactualcompressionoftherubbergrommet)thenturn
two(2)moreturns.
CONNECTING THE AIR HOSES
FollowFigure4for air hose arrangement.
1. TheTrailer System-Guard™air dryer supply and control
linefittingsare1/4"-18NPT.Cutthesupplyandcontrol
lines and install 1/4 inch fittings.
TrailerSystem Guard™Air Dryer
Grommet
Stud
Washer
Locknut
Grommet
FrameRail
ViseGrip
ClampingArea
FIGURE 3 - TRAILER SYSTEM-GUARD™AIR DRYER INSTALLATION
Templatefor mounting holes
Template10.25inches
Templatefor mounting holes
2.0 inches

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2. Connect the supply and control lines to the Trailer
System-Guard™airdryermakingsuretokeepthecontrol
and supply circuits separate as shown. Do not switch
lines end to end. All ports are identified as indicated in
figures1and2.
3. Affix theAlcohol Warning Decal to the trailer bulkhead.
Before applying the decal remove all oil and road
contaminants from the mounting location with a good
cleaningsolvent.
OPERATIONAL TEST
Buildthe airsystemtogovernor cutout. Shutoffthe engine.
Using a soap solution, check all lines and fittings leading
toand from theTrailerSystem-Guard™airdryer for leakage
andintegrity. Repairany excessive leaks - exceedinga 1"
bubblein 5 seconds - before restoring vehicleto service.
Supply
Trailer
System-Guard™Air
Dryer
FIGURE 4 -TRAILER SYSTEM-GUARD™AIR DRYER PLACEMENT
"12 IN
SUP"
"11 IN
CONT"
R-12™Relay
Valve
Spring
Brake
Valve
Reservoir
"22 OUT
SUP"
"21 OUT
CONT"
Spring
Brake
If the trailer is equipped with an R-12P™
valve, the trailer systems guard must be
mounted upstream of the R-12P™valve.

6BW2083 © 2004 Bendix Commercial Vehicle Systems LLC All rights reserved. 7/2004 Printed in U.S.A.
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