BENDIX FD-2 CLUTCH TYPE FAN DRIVE User manual

Brand: BENDIX

Model: FD-2 CLUTCH TYPE FAN DRIVE

Type: User manual

BENDIX FD-2 CLUTCH TYPE FAN DRIVE is an air operated thermostat controlled clutch for the engine cooling fan. Its purpose is to maintain engine temperature by engaging or disengaging the cooling fan, thereby providing better fuel economy, greater engine efficiency, faster warm-ups, and a quieter vehicle.

The FD-2™ fan clutch replaces the standard fan hubs on the engine and interchanges with other Bendix and competitive fan clutches. It is controlled by a temperature sensitive air valve.

Installed in the engine block, the control valve directly senses coolant temperature.

The FD-2™ fan clutch replaces the standard fan hubs on the engine and interchanges with other Bendix and competitive fan clutches. It is controlled by a temperature sensitive air valve.

Installed in the engine block, the control valve directly senses coolant temperature.

Bendix® FD-2™ Clutch Type Fan Drive

SD-09-8503

FIGURE 1

FIGURE 2

DESCRIPTION

The Bendix® FD-2™ fan clutch is an air operated thermostat

controlled clutch for the engine cooling fan. Its purpose is

to maintain engine temperature by engaging or disengaging

the cooling fan, thereby providing better fuel economy,

greater engine efficiency, faster warm-ups, and a quieter

vehicle.

The FD-2™ fan clutch is produced in several different models

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

The FD-2™ fan clutch replaces the standard fan hubs on the

engine and interchanges with other Bendix and competitive

fan clutches. It is controlled by a temperature sensitive air

valve (see Figure 5). The same valves used to control radiator

shutters are used to control the FD-2™ fan clutch. Installed

in the engine block, the control valve directly senses coolant

temperature. Provided coolant temperature remains below

the setting of the valve, air passes through it to disengage

the fan clutch. When coolant temperature rises to the valve

setting, the valve closes and exhausts air pressure from the

fan clutch which engages the fan.

PRESSURE PLATEBEARINGS

BRACKET

SHAFT

PISTON

DRIVE PIN

DUST

CAP

LOCK

NUT

FAN HUB

RETURN SPRING

PULLEY

AIR INLET

BEARINGS

PISTON HOUSING

FIGURE 3

FIGURE 5

FAN DISENGAGED

FIGURE 4

FAN ENGAGED

FIGURE 6

THERMO-PNEUMATIC

VALVE

THERMO-PNEUMATIC

VALVES

BLOCK

FAN

CLUTCH

RADIATOR

FAN

CLUTCH

BLOCK

SHUTTER

Depending upon optional equipment installed on the vehicle

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 70-75 psi, the piston slides on the

shaft moving the pressure plate assembly to the disengaged

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 3).

ENGAGED

As the engine coolant rises in temperature, the engine

thermostat opens to circulate radiator coolant through the

engine. When the engine coolant temperature reaches the

setting of the control valve, the valve exhausts air from the

piston cavity. The fan clutch springs force the piston and

pressure plate forward on the shaft. When the lining

contacts the fan plate, the fan is engaged and is driven by

the engine (see Figure 4).

FIGURE 7

FIGURE 8

BLOCK

THERMO-PNEUMATIC

VALVE

THERMO-PNEUMATIC

VALVES

FAN

OVERRIDE

SWITCH

AIR

CONDITIONING

SIGNAL

AIR COND.

COMPRESSOR

SOLENOID

VALVE

FAN

CLUTCH

RADIATOR

CONDENSER

RECEIVER

DRYER

AIR

CONDITIONING

OVERRIDE

SWITCH

FAN

CLUTCH

RADIATOR

SHUTTER

SOLENOID VALVE

(NORMALLY OPEN)

AIR

CONDITIONING

SIGNAL AIR

CONDITIONING

OVERRIDE

SWITCH

FAN

OVERRIDE

SWITCH

RECEIVER

DRYER

CONDENSER

AIR COND.

COMPRESSOR

CONTROL SYSTEMS

The fan clutch, in addition to its primary function of operating

the fan as needed to maintain the cooling liquid within a

certain temperature range, 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 5. Fan Clutch only

Figure 6. Fan Clutch with shutters

Figure 7. Fan Clutch with radiator mounted air

conditioning condenser

Figure 8. Fan Clutch, shutters and condenser

The objective in the case of Figure 5 is to not engage the fan

until the engine thermostat is fully open. The thermo-

pneumatic control valve should therefore be calibrated to

release the air from the fan clutch when the coolant

temperature is at least 10°F. higher than the shutter opening

point. If the shutters are the modulating type, the fan

engagement should be at least 10°F. higher than the full-open

temperature of the shutter.

In the case of Figure 7 the fan must be controlled to perform

the supplementary function of pulling cooling air through the

air conditioning condenser when required, 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 7). When this pressure switch senses

a higher than normal pressure in the air conditioning system

(approximately 250 psi), it closes an electrical circuit which

in turn energizes a solenoid operated air supply valve which

exhausts the air supply for the fan control, causing the fan

to engage. Most vehicles also have an additional dual function

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 is to prevent operation of the air conditioning

compressor if the refrigerant is lost or to shut off the

compressor if the system pressure reaches a dangerously

high pressure (approximately 400 psi). This switch does not

normally have anything to do with fan operation; however, it

is sometimes combined with the previously mentioned

override switch.

Figure 8 depicts a combination of shutters, fan clutch and

air conditioning. This combination requires the two thermo-

pneumatic controls for fan and shutters, as well as the electro-

pneumatic override for the air conditioning. With this

combination the same requirements for fan control apply as

in Figure 6 and 7 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

shutter with one section in front of the condenser and the

other in front of the remaining portion of the radiator. In this

combination only the section in front of the condenser needs

to open when the air conditioner engages.

PREVENTIVE MAINTENANCE

Important: Review the warranty policy before performing

any intrusive maintenance procedures. An extended warranty

may be voided if intrusive maintenance is performed during

this period.

Because no two vehicles operate under identical conditions,

maintenance intervals will vary. Experience is a valuable guide

in determining the best maintenance interval for a vehicle.

IGNITION

The durability of the Bendix® FD-2™ fan clutch matches that

of the vehicle’s engine. There is no need for periodic

maintenance; however, the following service checks should

be made to insure proper function of the fan clutch.

LINE HAUL VEHICLES:

Every 50,000 miles, 1,800 hours, or every six months,

whichever occurs first, perform the service checks outlined

in this manual.

CITY DELIVERY

Every 15,000 miles, 300 hours, or every two months,

whichever occurs first, perform the service checks outlined

in this manual.

SERVICE CHECKS

Before performing the operating and leakage checks, apply

the vehicle parking brakes or chock the wheels.

OPERATIONAL

1. With the engine cold, the ignition off and at least 75 psi

air pressure in the brake system, note that the fan is

disengaged from the pulley and can be turned by hand.

If the fan can be turned, proceed to Step #2. If it cannot

be turned:

A. Drain all reservoirs and disconnect the air control

line leading to the fan clutch and apply at least 75

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

leading to and from the thermostatic control valve for

“kinks” or obstructions, and check the control valve

itself according to the manufacturer’s instructions.

2. After performing Step #1, drain all air pressure from the

brake system. Note that the fan is now engaged and

cannot be turned by hand. If it cannot be turned,

proceed to Step #3. If it can be turned, the clutch is

defective and must be repaired or replaced.

3. Check the operation of the thermostatic control valve

by 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

should not exceed two minutes. If engagement time does

not exceed two minutes, proceed to Step #4. If

engagement time does 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

the setting of the engine coolant thermostat or in the

case of vehicles with radiator shutters, with the

setting of the shutter control. The fan clutch control

should always be 10° F. higher than the highest

setting.

B. If the fan clutch installation has successfully passed

this test before, but does not do so now, the

thermostatic control valve is defective and should be

replaced.

4. With the clutch in the engaged position (control air

vented), check the condition of the drive pins and mating

holes in the pressure plate by attempting to rotate the

fan clockwise and counter clockwise. If free play

exceeds 5/16" (806 MM), fan clutch must be repaired or

replaced.

LEAKAGE CHECKS

In order to check for air leakage past the only two sliding

o-rings in the FD-2™ fan clutch it is necessary to 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 stabilize and observe the time

required for the reservoir pressure to drop to 90 psi. If the

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 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, EXTREME CAUTION 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. 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.

FIGURE 10

27/32” DRILL THRU

(2 HOLES FOR 3/4" BAR) MATERIAL O.H.T.S. TUBING

HDN & DRAW RC 40-45

.235 + .002 CENTERED

(4 LUGS)

2.125 + .010

2-3/4”

1/32” FLAT

4-7/8”

5-1/8”6”

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

1. Remove the six cap screws and lockwashers that attach

the fan to the fan hub.

2. Remove fan. NOTE: Pay particular attention to any

spacers that may be installed between fan and pressure

plate.

3. Loosen fan belts.

4. Disconnect air line to fan clutch.

5. Remove cap nuts and lockwashers from mounting

bracket and remove unit from vehicle.

DISASSEMBLY (see Figure 9)

1. Remove dust cap (1) from end of fan hub.

2. Remove cotter pin (2) and nut (10) from end of shaft.

3. Remove fan plate (20) assembly and set aside.

4. Remove piston housing (15), remove piston (16) from

housing, remove two o-rings (4 & 6) from piston and one

o-ring (3) from shaft.

5. Remove pressure plate (7).

6. Remove anti-rotational spring (17) from shaft.

7. Remove two 1/4 x 20 Phillips screws and lift off spring

pack (8).

8. Disengage lock tab on lockwasher (19) and remove

lock nut (18), using a spanner tool (as shown in Figure

10). Remove lockwasher(19).

9. 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 Locktite between shaft and

bearings, a force as high as 5,000 lbs. may be required

to remove the pulley assembly.

PULLEY DISASSEMBLY (see Figure 11)

1. Support pulley on front end. Displace spacer (1)

eccentrically as far as possible. With a round pressing

tool which fits loosely through the I.D. of the top bearing,

press the bottom bearing out (3) pressing on the

eccentrically positioned spacer.

FIGURE 9

584

14 2

FIGURE 11

FIGURE 12

DRIVE PINS

PULLEY

SEAL

BEARINGS THIS END INSTALLED IN

NOTCH IN SHAFT

ANTI-ROTATIONAL

SPRING

2. Remove the tapered snap ring (2), using Waldes Tool

#6500. The remaining bearing (4) may now be pressed

out towards the rear of the pulley, leaving snap ring (5) in

pulley if pulley is to be reused.

3. Remove the two drive pins from the pulley. (Only if they

are to be replaced.) Use a stone grinding wheel and

grind a grove into the pin in such a manner that a puller

will grip the pin. Remove and discard same.

FAN PLATE DISASSEMBLY

1. Place fan plate (20) on flat surface nose down. Displace

spacer (12) between bearing eccentrically as far as

possible. With a round pressing tool which fits loosely

through the I.D. of the top bearing, contact spacer(12)

and force lower bearing (11) out of housing of fan plate

(20).

2. Remove retaining ring (14), using Waldes tool #6500,

turn hub plate over and press out bottom bearing (13).

RE-ASSEMBLY

Assembly of pulley-bearing sub-assembly (see Figure 11):

1. Install snap ring (5) using Waldes Tru-arc snap ring plier

#6500 or equivalent.

2. Support the pulley on the drive pin end. Press in bearing

(4) seal side up, until bearing bottoms on snap ring (5).

Pressing fixture should contact outer race.

3. Install tapered snap ring (2), flat side towards bearing

using Waldes tool #6500.

4. Invert pulley drive pin end up. Position spacer (1)

concentric with inner race of previously installed bearing.

Pack grease (Chevron SR1 #2) around spacer. Press

in second bearing (3), seal side up, until inner race

contacts spacer. Pressing fixture must contact both inner

and outer races.

5. If the drive pins were removed (under Step #3 “Pulley

Disassembly”), replace with new pins by placing pulley

on arbor press (or equivalent piece of equipment) -

drive pin side of pulley up. Start tapered end of pin (small

end) into hole and press into place. Drive pins are to

extend 1-1/4 inches from the face of the pulley.

ASSEMBLY OF PULLEY ASSEMBLY ON

BRACKET- SHAFT

1. Support bracket with shaft pointing up. Apply one band

of Loctite RC601 around shaft for each bearing (see

Figure 9). Apply one band of Loctite RC601 on each

race. NOTE: When using Loctite, parts must be clean

and free of oil and grease. Allow 24 hours for complete

curing.

2. Slide pulley assembly on shaft, making sure the bottom

bearing inner race bottoms against bracket.

3. Place locking ring (19) on shaft and install lock nut (13).

A tool similar to that shown in Figure 10 may be

fabricated to tighten the lock nut to 100-150 ft. lbs. One

tang on the locking ring (19) must be bent up into the

appropriate slot in the lock nut (13).

ASSEMBLY OF FAN PLATE SUB-ASSEMBLY

1. Place fan plate (20) on flat surface nose up and press

front bearing (11) seal up into housing until it bottoms

against shoulder of fan plate.

THIS END INSTALLED IN

NOTCH IN SPRING COLLAR

2. Turn fan plate assembly (20) over and install spacer

(12)concentric with inner race of previously installed

bearing. Pack grease (Chevron SR1 #2) around spacer.

Press in second bearing (13) seal side up until inner

race contacts spacer. Pressing fixture must contact both

inner and outer racer.

3. Install snap ring (14) flat side towards bearing.

FINAL ASSEMBLY

1. Support bracket, shaft, pulley assembly with the shaft

pointing up.

2. Install spring pack (8) onto pulley assembly and retain

with two 1/4 x 20 Phillips screws. Torque to 50-75 inch

pounds.

3. Install anti-rotational spring (17) making sure one end

of spring is engaged in notch of shaft (see Figure 12).

4. Install pressure plate (7) making sure end of anti-

rotational spring (17) is engaged in notch of spring collar.

Holes in pressure plate must slide over drive pins (9).

5. Press special washer (5) on hub of piston assembly

(16).

6. Lubricate I.D. of piston housing (15) and three o-rings

(3, 4, 6) with BW-655-M.

7. Install o-rings (6 & 4) onto piston (16) and install

o-ring (3) onto shaft.

8. Install piston (16) into piston housing (15) and install

unit onto shaft.

9. Install fan plate assembly (20) onto shaft and retain with

lock nut (3). Torque to 75 foot pounds.

10.Install and bend cotter pin (2) and replace cap (1).

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 pressure plate with six cap screws and

lockwashers. Torque to 300-360 inch pounds. (Be sure

to install any spacers that were removed during

Disassembly.)

5. Perform service checks as previously outlined.

TEST

1. With no air pressure applied, the torque required to

rotate the clutch must not exceed 150 inch ounces.

2. With 70-75 psi applied, the fan plate must rotate freely,

separate from the pulley.

3. Perform the leakage checks outlined in the manual.

RETROFIT INSTALLATION INFORMATION

To determine which fan clutch piece number should be

purchased when retrofitting existing equipment, consult the

nearest authorized Bendix distributor for assistance.

Complete installation instructions and piping diagrams are

packed with each FD-2™ fan clutch.

It is recommended that only cooling fans approved by the

vehicle or fan manufacturer be installed on the FD-2™ fan

clutch.

• Maximum weight of fan blade assembly is 30 lbs.

• Maximum R.P.M. of 28 inch fan is 2700.

• Maximum R.P.M. of 34 inch fan is 2100.

• Maximum thickness of spacers between fan and hub

plate is 1-1/2".

BENDIX FD-2 CLUTCH TYPE FAN DRIVE User manual

Brand: BENDIX

Model: FD-2 CLUTCH TYPE FAN DRIVE

Type: User manual

The FD-2™ fan clutch replaces the standard fan hubs on the engine and interchanges with other Bendix and competitive fan clutches. It is controlled by a temperature sensitive air valve.

Installed in the engine block, the control valve directly senses coolant temperature.

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BENDIX FD-2 CLUTCH TYPE FAN DRIVE User manual

BENDIX FD-2 CLUTCH TYPE FAN DRIVE User manual

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