BENDIX FD-L FAN CLUTCH User manual

Brand: BENDIX

Model: FD-L FAN CLUTCH

Type: User manual

BENDIX FD-L FAN CLUTCH is an air-operated thermostatically controlled clutch for the engine cooling fan. It maintains engine temperature by engaging or disengaging the cooling fan, providing better fuel economy, greater engine efficiency, faster warm-ups, and a quieter vehicle. It withstands a maximum fan torque of 750 inch pounds and a fan weight not exceeding 15 pounds. It features a fail-safe design preventing overheating in case of air loss.

FAN HUB

DUST CAP

BRACKET

PULLEY

Bendix

FD-L

™

Fan Clutch

SD-09-8505

FIGURE 1

PRESSURE PLATE

BEARINGS

SPACER

PISTON COMPLETE

WASHER

SPRING

COTTER PIN

HEX NUT

PISTON HOUSING

BEARINGS

HEX NUT

CAP

ISOLATOR

O-RING

LOCKWASHER

O-RING

SPACER

FIGURE 3

FAN DISENGAGED

FIGURE 2

FAN ENGAGED

The FD-L

™

fan clutch is designed for mid-range diesel engine

applications and can withstand maximum fan torque of 750

inch pounds and a fan weight not to exceed 15 pounds. It

cannot be used to replace heavy duty clutches or hubs that

do not meet the above stated specifications.

DESCRIPTION

The Bendix

FD-L

™

fan clutch is an air operated

thermostatically 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-L

™

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-L

™

fan clutch replaces the standard fan hubs on 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,

the thermo-pneumatic 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.

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 75-80 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 2).

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 pressure

plate forward until the lining contacts the fan plate. The fan

is engaged and is driven by the engine (see Figure 3).

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 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

FORWARD AS AIR IS

EXHAUSTED

FIGURE 5

FIGURE 7

FIGURE 6

FIGURE 4

THERMO-PNEUMATIC

VALVE

THERMO-PNEUMATIC

VALVES

BLOCK

FAN

CLUTCH

RADIATOR

FAN

CLUTCH

BLOCK

SHUTTER

BLOCK

THERMO-PNEUMATIC

VALVE

THERMO-PNEUMATIC

VALVE

FAN

OVERRIDE

SWITCH

AIR

CONDITIONING

SIGNAL

AIR COND. COMPRESSOR

SOLENOID VALVES

(NORMALLY OPEN)

FAN

CLUTCH

RADIATOR

CONDENSER

RECEIVER

DRYER

AIR

CONDITIONER

OVERRIDE

SWITCH

FAN

CLUTCH

RADIATOR

SOLENOID VALVE

AIR

CONDITIONING

SIGNAL

AIR

CONDITIONING

OVERRIDE

SWITCH

FAN

OVERRIDE

SWITCH

RECEIVER

DRYER

CONDENSER

AIR COND.

COMPRESSOR

SHUTTER

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

until the shutters are 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 full-open temperature of the shutter.

In the case of Figure 6, 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 6. 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

FAN PLATE

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

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 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

shutter with one section in front of the condenser and 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

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

lateral movement of the fan plate relative to the edge of the

pulley or a scribed line on the lining surface, when air is

applied.

CHECKING PROCEDURES

1. Park the vehicle on a level surface and block the wheels.

2. Shut off the engine and apply a minimum of 85 psi to

the fan clutch to disengage it. NOTE: If air brake system

pressure is above 85 psi and the engine is cool, the

FD-L

™

fan clutch will be disengaged. Disengagement is

confirmed by noting that the fan can be rotated freely by

hand. DO NOT PERFORM THIS CHECK WITH ENGINE

RUNNING.

3. With the engine off and the FD-L

™

fan clutch disengaged,

grasp the tip of one blade using only the thumb and

index finger. (Refer to Figure 8). Using a moderate force,

rock the fan blade back and forth toward the radiator

and measure the total movement of the fan plate 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,

whichever occurs first, perform the service checks out lined

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. With the engine cold, the ignition off and at lease 85 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 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

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 check #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 test #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 check #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 or thermostat are defective

and should be replaced.

LEAKAGE CHECKS

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

o-rings in the FD-L

™

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 stabilized 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.

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

some installations to install kits 106733 and 106732 without

clutch removal.

1. Secure the vehicle on a level surface by means other

than the brakes.

2. Drain ALL reservoirs to 0 psi (0 kPa) air pressure.

3. Disconnect the air line from the fan clutch.

4. Remove the six cap screws and lockwashers that attach

the vehicle’s fan to the fan plate of the FD-L

™

fan clutch.

FIGURE 9

5. Remove the fan. NOTE: Remove and retain any spacers

that may be installed between fan and fan plate

assembly.

6. Loosen, remove and retain the vehicle’s fan belts.

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)

and remove the o-ring (3).

5. Remove the o-rings (2 & 4) from the shaft.

6. Remove the pressure plate (6) and the six springs (7).

7. Disengage the lock tabs on lockwasher (17) and using a

1-9/16” socket, remove hex nut (16) and the 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

the original length.

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.

Key Description Qty.

1 Coffer Pin 1

2 O-Ring

3 O-Ring

4 O-Ring

5 Cap

6 Pressure Plate

Complete 1

Key Description Qty.

7 Spring 6

8 Isolator 3

9 Washer 1

10 Spacer 1

11 Ball Bearing 2

12 Hex Nut 1

Key Description Qty.

13 Piston Housing 1

14 Piston Complete 1

15 Bearing 2

16 Hex Nut 1

17 Lockwasher 1

18 Spacer 1

2. Support the pulley on the bracket side in such a manner

that the support will not interfere with the removal of 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

disassembly and must be replaced.

3. Remove the three isolators (8) from the bosses of the

pulley. They may require turning and at the same pulling

until they disengage from their seats.

FAN PLATE DISASSEMBLY

1. Support the fan mounting surface of the fan plate

assembly making certain sufficient space is left beneath

to permit the ball bearings(11) to be pressed out. Use a

pressing tool of adequate diameter to contact the outer

race of the ball bearing, press out both ball bearings

(11) and the spacer (10). The bearing must be replaced

once removed.

CLEAN & INSPECT

1. Prior to assembly, wash all metal parts thoroughly using

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)

PULLEY ASSEMBLY

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. Install the second ball bearing (15) into the housing and

using the pressing tool, press until contact has been

made on the spacer. (Do not use a force greater than

1,100 lbs.) Do not continue pressing the bearing once

the inner race has touched the spacer or severe damage

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

finger load.

4. Install the three isolators (8) onto their seats on the pulley

making certain they are fully seated.

ASSEMBLY OF PULLEY ONTO THE BRACKET AND

SHAFT

1. Support the bracket with the shaft pointing up. Apply

one band of Loctite RC609 around the shaft at the location

of inner races of the bearings (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

Loctite to properly bond.

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

the same tool as Step 7 of “Disassembly.” Torque hexnut

to 80-130 ft. lbs. until two of the tangs of the lockwashers

(17) can be bent up against the flats of the locknut.

Never back the 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

the pressing tool used in disassembly procedure, press

one of the ball bearings (11) into the housing until it

contacts the lip of the bore. (Do not use a force greater

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

each ball bearing but able to be moved by a finger load.

FINAL ASSEMBLY

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

shaft pointing up.

2. Install the six springs (7) on the pulley. Three into the

isolators (8) and three onto the bosses 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

three o-rings (2-3-4). Install o-ring (2 & 4) onto the shaft

and o-ring (3) into the groove of the piston (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

installed on the pulley assembly.

5. Lubricate the I.D. of the piston housing (13) with the

same lubricant used on the o-rings in Step 3. Install the

piston (4) (with o-ring (3) in place) into the piston housing.

Install the piston and housing assembly onto the shaft,

making sure the flats on the I.D. of the piston mate with

the flats on the shaft.

WARNING: FAILURE TO PROPERLY MATCH THE FLATS

OF THE PISTON TO THE FLAT OF THE SHAFT WILL

RESULT IN SEVERE DAMAGE TO THE UNIT.

6. Place the fan plate assembly onto 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. With no air pressure applied, the torque required to rotate

the clutch must not exceed 150 in. oz.

2. With 75-80 psi applied, the fan plate must separate from

the pulley and rotate freely.

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

to install any spacers that were removed during

disassembly.)

5. Perform service checks as previously outlined.

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 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.

Maximum weight of fan blade assembly is 15 lbs.

Maximum thickness of spacers between fan and hub plate

is 1-1/2”.

BENDIX FD-L FAN CLUTCH User manual

BENDIX FD-L FAN CLUTCH User manual

BENDIX FD-L FAN CLUTCH User manual

Related papers

Other documents