BENDIX FD-L FAN CLUTCH User manual

1
®
FANHUB
DUST CAP
BRACKET
PULLEY
Bendix®FD-L™Fan Clutch
SD-09-8505
FIGURE 1
PRESSUREPLATE
BEARINGS
SPACER
PISTON COMPLETE
WASHER
SPRING
COTTER PIN
HEX NUT
PISTON HOUSING
BEARINGS
HEX NUT
CAP
ISOLATOR
O-RING
LOCKWASHER
O-RING
O-RING
SPACER

2
FIGURE 3
FANDISENGAGED
FIGURE 2
FANENGAGED
TheFD-L™fanclutchisdesignedformid-rangedieselengine
applicationsandcanwithstandmaximumfantorqueof750
inch poundsand a fanweight not to exceed 15 pounds. It
cannotbeusedtoreplace heavy duty clutches or hubs that
do not meet the above stated specifications.
DESCRIPTION
The Bendix®FD-L™fan clutch is an air operated
thermostaticallycontrolledclutchfor the enginecoolingfan.
Itspurposeis to maintain engine temperature by engaging
ordisengagingthe coolingfan,thereby,providingbetter fuel
economy,greaterengineefficiency,fasterwarm-upsand a
quietervehicle.
TheFD-L™fanclutch isproducedin severaldifferentmodels
to accommodate the variety of installation requirements
resulting from the many engine, vehicle and accessory
combinations. Its fail-safe design prevents overheating in
the event of air loss for any cause.
OPERATION
GENERAL
TheFD-L™fanclutch replaces thestandardfanhubson the
engine of mid-range diesel vehicles. It is controlled by a
temperature sensitive air valve. (See Figure 4). The same
type of valves used to control radiator shutters are used to
control the FD-L™fan clutch. Installed in the engine block,
thethermo-pneumaticcontrolvalvedirectly senses coolant
temperature.Providedcoolanttemperatureremainsbelow
the setting of the valve, air passes through it to disengage
thefanclutch.Whencoolanttemperaturerisestothevalve
setting,thevalvecloses and exhaustsairpressurefromthe
fanclutchwhichengages the fan.
Dependinguponoptionalequipmentinstalledon thevehicle
such as radiator shutters and radiator mounted air
conditioning condenser, different piping arrangements are
necessary. These will be explained in the paragraph on
control systems.
DISENGAGED
When the vehicle is started with a cold engine the thermo-
pneumatic control valve is open. As brake system air
pressure is built up, air passes through the control valve to
the fan clutch. Air enters the inlet port in the bracket of the
fan clutch and travels through the drilled passage in the
shaft to fill the piston cavity. When air in the piston cavity
reaches a pressure of 75-80 psi, the piston slides on the
shaftmoving thepressureplate assemblytothedisengaged
position. In this position the clutch lining is out of contact
with the fan plate and the fan is no longer driven by the
engine (see Figure 2).
ENGAGED
As the engine coolant rises in temperature, the engine
thermostat opens to circulate radiator coolant through the
engine.Whentheenginecoolanttemperaturereachesthe
setting of the control valve, the valve exhausts air from the
piston cavity. The fan clutch springs force the pressure
plateforwarduntil the lining contacts the fan plate. Thefan
is engaged and is driven by the engine (see Figure 3).
CONTROL SYSTEMS
Thefanclutch,inadditionto itsprimaryfunctionof operating
the fan as needed to maintain the cooling liquid within a
certaintemperaturerange,must be coordinated with other
devices when installed on the vehicle; these are radiator
shutters and radiator mounted condenser for air
conditioning. Four basic configurations are possible as
follows:
FIGURE 4. FAN CLUTCH ONLY
FIGURE 5. FAN CLUTCH WITH SHUTTERS
FIGURE 6. FAN CLUTCH WITH RADIATOR MOUNTED
CONDITIONING CONDENSER
FIGURE 7. FAN CLUTCH, SHUTTERS AND CONDENSER
PISTON MOVES
FORWARDASAIRIS
EXHAUSTED

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FIGURE 5
FIGURE 7
FIGURE 6
FIGURE 4
THERMO-PNEUMATIC
VALVE
THERMO-PNEUMATIC
VALVES
BLOCK
FAN
CLUTCH
RADIATOR
RADIATOR
FAN
CLUTCH
BLOCK
SHUTTER
BLOCK
BLOCK
THERMO-PNEUMATIC
VALVE
THERMO-PNEUMATIC
VALVE
FAN
OVERRIDE
SWITCH
AIR
CONDITIONING
SIGNAL
AIRCOND.COMPRESSOR
SOLENOID VALVES
(NORMALLY OPEN)
FAN
CLUTCH
RADIATOR CONDENSER
RECEIVER
DRYER
AIR
CONDITIONER
OVERRIDE
SWITCH
FAN
CLUTCHRADIATOR
SOLENOIDVALVE
AIR
CONDITIONING
SIGNAL
AIR
CONDITIONING
OVERRIDE
SWITCH
FAN
OVERRIDE
SWITCH
RECEIVER
DRYER
CONDENSER
AIRCOND.
COMPRESSOR
SHUTTER
Theobjectivein thecaseofFigure 5istonot engagethefan
untiltheshuttersarefullyopen.Thethermo-pneumaticcontrol
valveshouldtherefore be calibrated to release the air from
thefanclutchwhen the coolant temperatureisatleast10°F
higherthanthefull-opentemperatureoftheshutter.
Inthecase ofFigure6, thefanmustbe controlledtoperform
the supplementary function of pulling cooling air through
theairconditioningcondenserwhenrequired, although the
engine coolant may be below the fan cut-in temperature.
This is most likely to occur at high ambient temperatures
and low road speed or idling. If the condenser is
inadequately cooled, the air conditioning system will start
to build up a higher than normal pressure. Therefore, a
pressure switch is connected into the air conditioning
compressor discharge line, as shown in Figure 6. When
thispressureswitchsensesahigher than normal pressure
in the air conditioning system (approximately 250 psi), it
closesanelectricalcircuitwhichin turnenergizesasolenoid
operatedairsupplyvalvewhich exhausts the air supply for
the fan control, causing the fan to engage.
Mostvehicles alsohavean additionaldualfunction pressure
switch connected in series with the air conditioner clutch.
This switch is normally open, closes at approximately 30
psi and opens again at approximately 400 psi. Its purpose
istopreventoperationoftheairconditioningcompressorif
the refrigerant is lost or to shut off the compressor if the
system pressure reaches a dangerously high pressure
(approximately400psi). Thisswitchdoes notnormallyhave
anythingtodowith fan operation; however,itissometimes
combinedwiththepreviouslymentionedoverrideswitch.

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FIGURE 8
FANPLATE
DUST SHIELD
PULLEY
THE TOTAL CHANGE IN THIS
DIMENSION FROM ITS
NARROWEST TO WIDEST
MEASUREMENT SHOULD
NOT BE 1/16” OR GREATER
Figure 7 depicts a combination of shutters, fan clutch and
airconditioning.Thiscombinationrequiresthetwothermo-
pneumatic controls for fan and shutters, as well as the
electro-pneumaticoverridefor theairconditioning.Withthis
combinationthesame requirements forfancontrolapplyas
in Figure 5 and 6 with the additional requirement that the
shutters should be controlled in such a manner that they
always open whenever the air conditioning compressor
operates.
A variation of this combination consists of a two section
shutterwithonesectioninfrontofthecondenserandother
in front of the remaining portion of the radiator. In this
combinationonlythesectioninfrontofthecondenser needs
to open when the air conditioner engages.
PREVENTIVE MAINTENANCE
There is no need for periodic maintenance; however, the
following service checks should be made to ensure proper
function of the fan clutch.
GENERAL
The condition of the two fan plate ball bearings should be
checked at regular intervals to ensure proper operation of
the FD-L™fan clutch. The procedure presented here is
intended to check excessive bearing play by measuring
lateralmovementofthefanplaterelativetotheedgeofthe
pulley or a scribed line on the lining surface, when air is
applied.
CHECKING PROCEDURES
1. Park thevehicleon alevelsurfaceandblockthewheels.
2. Shut off the engine and apply a minimum of 85 psi to
thefanclutchto disengage it.NOTE:Ifairbrake system
pressure is above 85 psi and the engine is cool, the
FD-L™fanclutchwillbedisengaged.Disengagementis
confirmedbynotingthat the fan canberotatedfreelyby
hand.DONOTPERFORMTHISCHECKWITHENGINE
RUNNING.
3. WiththeengineoffandtheFD-L™fanclutchdisengaged,
grasp the tip of one blade using only the thumb and
indexfinger.(RefertoFigure8).Usinga moderateforce,
rock the fan blade back and forth toward the radiator
andmeasurethetotalmovementof thefanplate relative
to the edge of the pulley. Replace or repair the fan
clutch if the total movement of the fan plate is 1/16" or
greater.
LINE HAUL VEHICLES
Every 50,000 miles, 1,800 hours, or every six months,
whicheveroccursfirst,performthe service checks outlined
in this manual.
CITY DELIVERY
Every 15,000 miles, 300 hours or two months, whichever
occurs first, perform the service checks outlined in this
manual.
SERVICE CHECKS
Before performing the operational and leakage checks,
apply the vehicle parking brakes or chock the wheels.
OPERATIONAL
1. Withtheenginecold,theignitionoffand at lease 85 psi
air pressure in the brake system, note that the fan is
disengagedfromthepulleyandcanbeturnedbyhand.
Ifthe fan can be turned, proceed to Step #2. If it cannot
beturned:
A. Drain all reservoirs and disconnect the air control
line leading to the fan clutch and apply at least 85
psi shop air pressure to the fan clutch.
B. If the fan cannot be turned, the clutch is defective
and must be repaired or replaced (see appropriate
section of this manual).
C. If the fan can now be turned, check the air lines
leadingtoandfromthethermostatic controlvalvefor
“kinks” or obstructions, and check the control valve
itselfaccordingto the manufacturer’s instructions.

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2. Afterperformingcheck #1,drainallair pressurefromthe
brake system. Note that the fan is now engaged and
cannotbe turnedbyhand. Ifitcannot beturned,proceed
totest#3. If it can be turned, the clutchisdefective and
mustberepairedorreplaced.
3. Checktheoperationof the thermostaticcontrolvalveby
running the engine up to operating temperature. Note
that the fan clutch engages when engine temperature
rises to normal or above and disengages after fan
cooling is accomplished. Normal engagement time
shouldnotexceedtwominutes.Ifengagementtimedoes
not exceed two minutes, proceed to check #4. If
engagementtimedoes exceed two minutes:
A. If this test is being performed for the first time after
installation of the fan clutch, recheck the setting of
the thermostatic control valve and compare it with
thesettingofthe engine coolant thermostatorinthe
case of vehicles with radiator shutters, with the
setting of the shutter control. The fan clutch control
shouldalwaysbe10°Fhigherthanthehighestsetting.
B. Ifthefanclutchinstallationhassuccessfully passed
this test before, but does not do so now, the
thermostaticcontrolvalveorthermostataredefective
andshouldbereplaced.
LEAKAGE CHECKS
In order to check for air leakage past the only two sliding
o-ringsinthe FD-L™fan clutch,itisnecessaryto disconnect
the single air control line.
Check for leakage by connecting a 90 cu. in. reservoir
(Bendix part number 225000) with a gauge installed to the
control port of the fan clutch. After filling the 90 cu. in.
reservoir with 100 psi, allow the pressure to stabilized and
observethetimerequiredforthe reservoir pressure to drop
to90psi.Ifthe time required is less than 1 minute, leakage
is excessive and repair or replacement is necessary.
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
enginebein operation, EXTREMECAUTION should
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. Useonlythe proper tools andobserve
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 certaintodrain 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,deactivate theelectrical
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.
REMOVAL
It is recommended that the FD-L™fan clutch be removed
from the vehicle for service even though it is possible on
someinstallationstoinstall kits106733and106732without
clutchremoval.
1. Secure the vehicle on a level surface by means other
thanthebrakes.
2. DrainALLreservoirs to 0 psi (0 kPa) air pressure.
3. Disconnect the air line from the fan clutch.
4. Removethesix capscrewsandlockwashers thatattach
thevehicle’sfantothe fan plate of theFD-L™fanclutch.

6
FIGURE 9
15
5. Removethefan. NOTE:Removeandretainanyspacers
that may be installed between fan and fan plate
assembly.
6. Loosen,removeandretainthevehicle’sfanbelts.
7. Remove the attaching hardware from the fan clutch
mounting bracket and remove the fan clutch from the
vehicle.
DISASSEMBLY (REFER TO FIGURE 9)
1. Remove dust cap (5). Remove the cotter pin (1) from
the locknut (12). Remove the locknut (12) and washer
(9).
2. Remove the fan plate assembly and set aside.
3. Slide the piston housing (13) and piston (14) off the
shaft.
4. Separate the piston (14) from the piston housing (13)
andremovethe o-ring (3).
5. Removetheo-rings(2 & 4) from the shaft.
6. Remove the pressure plate (6) and the six springs (7).
7. Disengagethelocktabs onlockwasher(17)and usinga
1-9/16”socket,remove hexnut(16)andthe lockwasher
(17).
NOTE: To fabricate a tool to remove the 1-9/16” hex nut,
take two deep sockets and cut the end out of one
and weld the remaining length onto the bottom of
the other socket to make it approximately double
theoriginallength.
PULLEY DISASSEMBLY
1. Support the backside of the pulley so that the shaft
bracket assembly can be pressed down far enough to
remove the pulley assembly. Since the bearings are
originally installed with Loctite between the shaft and
bearings, a force as high as 5000 lbs. may be required
to remove the pulley assembly. The bearings will be
damaged after this point of disassembly and must be
replaced.
87
17 16
614 13 11
10 9
2
3
4
18 1
12 5
Key Description Qty.
1 CofferPin 1
2 O-Ring
3 O-Ring
4 O-Ring
5 Cap
6 PressurePlate
Complete 1
Key Description Qty.
7 Spring 6
8 Isolator 3
9 Washer 1
10 Spacer 1
11 Ball Bearing 2
12 HexNut 1
Key Description Qty.
13 Piston Housing 1
14 Piston Complete 1
15 Bearing 2
16 HexNut 1
17 Lockwasher 1
18 Spacer 1

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2. Supportthepulleyon the bracket sideinsuchamanner
thatthesupportwillnotinterferewiththeremovalof the
roller bearing (15). Use a pressing tool of adequate
diameter to engage the outer race of the ball bearing.
Press out both ball bearings (15) and the spacer (18).
The bearings will be damaged after this point of
disassemblyandmustbe replaced.
3. Remove the three isolators (8) from the bosses of the
pulley.Theymayrequireturningand atthesamepulling
until they disengage from their seats.
FAN PLATE DISASSEMBLY
1. Support the fan mounting surface of the fan plate
assemblymakingcertain sufficient spaceisleftbeneath
topermittheballbearings(11) to be pressed out. Usea
pressingtoolofadequate diameter to contact the outer
race of the ball bearing, press out both ball bearings
(11)andthespacer(10).Thebearingmustbereplaced
onceremoved.
CLEAN & INSPECT
1. Priortoassembly, wash allmetalpartsthoroughlyusing
a quality commercial solvent (such as mineral spirits).
2. Inspect all component parts for wear or damage and
replace any parts that fail this visual inspection.
ASSEMBLY (REFER TO FIGURE 9)
PULLEYASSEMBLY
1. Support the pulley drive end down and using the same
pressing tool as used in the disassembly procedure,
press one of the two ball bearings (15) into the pulley
until it contacts the lip on the pulley housing. (Do not
use a force greater than 1,100 lbs.)
2. Install the spacer (18) into the housing making it as
concentric as possible to the inner race of the bearing
installed in Step 1.
3. Installthesecondballbearing(15) into the housing and
using the pressing tool, press until contact has been
madeonthespacer.(Do not use a force greater than
1,100 lbs.) Do not continue pressing the bearing once
theinner racehastouchedthespacerorseveredamage
to the bearings may result.As a check after assembly,
the bearing spacer should be in contact with the inner
races of each ball bearing but able to be moved by a
fingerload.
4. Installthethreeisolators(8)ontotheirseatsonthepulley
making certain they are fully seated.
ASSEMBLY OF PULLEY ONTO THE BRACKET AND
SHAFT
1. Support the bracket with the shaft pointing up. Apply
onebandofLoctiteRC609aroundtheshaftatthelocation
ofinnerracesofthebearings(15)in the pulley.Also put
a band of the Loctite on the inner races of the bearings
(15). NOTE: Parts MUST BE free of oil and grease for
Loctitetoproperlybond.
2. Slide the pulley onto the shaft, making sure the bottom
bearings inner race contacts the bracket.
3. Place lockwasher (17) on the shaft engaging the I.D.
tab in the slot in the shaft and install hexnut (16) using
thesametoolasStep7of“Disassembly.”Torquehexnut
to80-130ft.lbs.untiltwo ofthetangsofthelockwashers
(17) can be bent up against the flats of the locknut.
Neverbackthe torque off to align parts. Allow 24 hours
for complete curing of the Loctite to take affect.
ASSEMBLY OF FAN PLATE
1. Place the fan plate face up on a level surface and with
thepressingtoolusedindisassembly procedure, press
one of the ball bearings (11) into the housing until it
contactsthelip ofthebore.(Donot use aforcegreater
than 700 lbs)
2. Install spacer(10) into the bore of the fan plate (as
illustrated in Figure 1) concentric with the inner race of
the ball bearing previously installed. (NOTE: Flanged
end of spacer (10) should be toward the forward nose
of the fan plate.)
3. Install the second ball bearing (11) into the bore of the
fan plate and utilizing the pressing tool used in Step 1,
press the ball bearing until it contacts the spacer (10).
(Do not use a force greater than 700 lbs.) Do not
continue pressing the bearing once the inner race has
touched the spacer, severe damage to the bearings
may result. As a check after assembly, the bearing
spacer should be in contact with the inner races of
eachballbearingbutabletobemovedbya finger load.
FINALASSEMBLY
1. Support thebracket,shaftandpulleyassemblywiththe
shaft pointing up.
2. Install the six springs (7) on the pulley. Three into the
isolators(8)and threeontothebosses provided. NOTE:
The isolators must be equally spaced around the
circumference of the pulley (every other spring).
3. Apply a thin film of silicone lubricant BW-665M to the
threeo-rings(2-3-4).Installo-ring(2&4)ontotheshaft
ando-ring(3)intothegrooveofthepiston(14).
4. Install the pressure plate (6) on the pulley assembly
making sure the bosses on the underside of the plate
mate with the O.D. of the six springs (7) previously
installedonthepulleyassembly.
5. Lubricate the I.D. of the piston housing (13) with the
samelubricantused on the o-rings in Step 3. Installthe
piston(4)(witho-ring (3)inplace)intothepistonhousing.
Install the piston and housing assembly onto the shaft,
makingsurethe flats on the I.D. of the piston matewith
the flats on the shaft.

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WARNING:FAILURETOPROPERLYMATCHTHEFLATS
OF THE PISTON TO THE FLAT OF THE SHAFT WILL
RESULTIN SEVERE DAMAGE TOTHEUNIT.
6. Placethefanplateassemblyonto the shaft, the washer
(9) and retain with locknut (12). Torque to 90-100 ft.
lbs.
7. Install cotter pin (1) and bend to hold in place. Install
dust cap (5). NOTE: Never back torque off to align the
cotter pin. If necessary increase torque slightly until
slots in locknut and hole in shaft are in line.
TEST
1. Withnoairpressureapplied,thetorquerequiredtorotate
the clutch must not exceed 150 in. oz.
2. With75-80psi applied,thefanplatemust separatefrom
thepulley and rotatefreely.
3. Perform the leakage checks outlined in the manual.
INSTALLATION
1. Attach fan clutch unit to vehicle by installing cap nuts
and lockwashers through mounting bracket holes into
mating holes in engine bracket.
2. Reconnect air line to unit.
3. Adjust fan belts per vehicle manufacturer’s
recommendation.
4. Replace fan on fan plate with six cap screws and
lockwashers.Torqueto300-360inchpounds.(Besure
to install any spacers that were removed during
disassembly.)
5. Performservicechecksaspreviouslyoutlined.
RETROFIT INSTALLATION INFORMATION
To determine which fan clutch piece number should be
purchasedwhenretrofittingexisting equipment, consult the
nearest authorized Bendix distributor for assistance.
Complete installation instruction and piping diagrams are
packed with each FD-L™fan clutch.
It is recommended that only cooling fans approved by the
vehicle or fan manufacturer be installed on the FD-L™fan
clutch.
Maximumweight of fan blade assembly is 15 lbs.
Maximumthickness of spacers between fan and hub plate
is 1-1/2”.
BW1603 © 2004 Bendix Commercial Vehicle Systems LLC All rights reserved. 4/2004 Printed in U.S.A.