Freightliner FLA/FLB/FLC/FLD/FLL. Manual - part 13

inches (3.8 mm) for the Kysor K22RA, the clutch
lining is worn and must be replaced. See Group
20 of the

Heavy-Duty Trucks Service Manual

for

overhaul instructions.

Release the air pressure, then disconnect the
shop hose from the air inlet of the air cylinder.
Connect the vehicle air hose to the inlet.

Connect the electrical cables to the battery. If
equipped with an air starter, charge the air
starter reservoir.

Start the engine. The LOW WTR light and warn-
ing buzzer should be off. If the light and buzzer
are off, the sensor is okay. If the light and buzzer
are on, replace the sensor.

Kysor/Dynair Fan Clutch Wear Limits

Model Numbers

Retaining

Plate

Fasteners

Wear Limit:

in (mm)

1090–05261–01
1090–05262–01
1090–05261–02
1090–05262–02

Bolt,

Lockwasher,

and Nut

0.16 (4.1)

1090–06620–01
1090–06060–01
1090–07050–01
1090–08000–01
1090–06620–02
1090–06060–02
1090–07050–02

Capscrew

and

Lockwasher

0.17 (4.3)

The fan clutch model number is stamped on the tag on the air cylinder.

Also, the models can be identified by the type of retaining plate fasteners
used.

Table 6, Kysor/Dynair Fan Clutch Wear Limits

f500006a

05/27/93

Capscrew

Mounting Bracket

Hexnut

Washer

Drive Sleeve

Friction Disc

Capscrew

Panhead Screw

Retaining Washer

10. Rotary Air Union
11. O-Ring Seal
12. Setscrew
13. Air Chamber Assembly

14. O-Ring Seal
15. Piston Assembly
16. Friction Facing
17. Capscrew
18. Washer
19. Compression Spring

Fig. 6, Horton HT 550 Fan Clutch Components

Engine Cooling/Radiator

Heavy-Duty Trucks Maintenance Manual, January 2007

20/8

Schwitzer Viscous Fan Drive

NOTE: After performing the checks below, if any
part of the fan drive requires service or replace-
ment, see Group 20 of the

Heavy-Duty Trucks

Service Manual for instructions.

Check the tightness of the fasteners attaching
the fan to the fan drive, and fan drive to the fan
hub. For torque values, see

Group 00

of this

manual.

Check the fan and surrounding area for signs of
physical contact between the fan and other parts.
If there has been contact, correct the cause. Re-
place all damaged parts.

Check the drive belts for fraying, cracking, and
correct tension; see Group 01 of the

Heavy-Duty

Trucks Service Manual

Turn the fan by hand at least one full turn. It
should turn smoothly, with some resistance. If
there is binding or jerkiness, or if the fan spins
freely, replace the fan drive.

Check the fan drive for fluid leakage. Very slight
misting and dust accumulation around the pin in
the center of the front cover is normal. Any other
leakage is abnormal, and will result in poor per-
formance. Replace the fan drive if there is abnor-
mal leakage.

Move one blade tip alternately toward and away
from the radiator. The allowable play is 1/16 inch
(1.6 mm) at a 10-inch (254-mm) radius from the
center of the fan. See

Fig. 8

. If there is greater

movement, and it can not be traced to loose fas-
teners or fan hub pulley bearing wear, replace
the fan drive.

NOTE: When making this check, use only
enough force to take up the play in the clutch
without bending the blade.

Horton DriveMaster

Fan Clutch

NOTE: If any part of the fan clutch needs to be
repaired or replaced after performing the checks
below, see Group 20 of the

Heavy-Duty Trucks

Service Manual.

f200237a

05/27/93

With the fan clutch engaged, measure the distance at

measure it again with the fan clutch disengaged.

Bearing Housing

Retaining Plate

Fan Pulley

Air Inlet (from the
solenoid valve)

Air Cylinder

Fan

Fig. 7, Kysor/Dynair and Kysor K22RA Fan Clutch

Lining Wear Checking

f200238

05/27/93

A = 10" (254 mm)
B = 1/16" (1.6 mm) maximum play

Fig. 8, Checking Schwitzer Viscous Fan Drive Wear

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Heavy-Duty Trucks Maintenance Manual, January 2007

20/9

Disconnect the batteries at the negative termi-
nals. Drain all air from the air system. If
equipped with an air starter, drain the air starter
reservoir.

WARNING

Make sure the batteries are disconnected before
checking the fan clutch. If the engine starts during
this procedure, the fan could engage, which could
result in serious personal injury.

Inspect the electrical connections and wires to
the fan clutch solenoid. Secure the connection if
loose; replace wires and connectors if damaged.

Clean the fan clutch air solenoid valve filter, if
equipped.

3.1

Unscrew the fan clutch solenoid valve air
filter assembly and remove the filter ele-
ment.

3.2

Clean the filter element with cleaning sol-
vent.

3.3

Using a clean, lint-free cloth, wipe off any
excess solvent.

3.4

Reassemble the clutch valve solenoid air
filter assembly and install it on the ve-
hicle.

Check the fan for bent, cracked, or damaged
blades; replace if damaged. Check for adequate
clearance between the fan and other compo-
nents.

Check the fan belt for wear, tension, and align-
ment. Correct if necessary.

Check for wear on the friction facing. Replace
the friction facing if it is worn to a 3/16-inch (4.8-
mm) thickness or less. Also check the facing for
signs of oil contamination or burn marks. If evi-
dence of oil or burn marks are found, replace the
friction facing.

Connect the battery cables. Start the engine, and
charge the air system to 120 psi (827 kPa).
Manually engage and disengage the fan clutch.

Check the fan and the fan clutch from a dis-
tance. Look for vibration, fan blade contact, fan
clutch slippage, and overall fan clutch operation.

If the fan clutch does not operate correctly, see
Group 20 of the

Heavy-Duty Trucks Service

Manual

for troubleshooting and repair proce-

dures.

With the air system charged to 120 psi (827
kPa), check the fan clutch for audible air leaks,
using a suitable listening device.

Check at the solenoid valve, the air filter assem-
bly, and the air hoses and fittings. See

Fig. 9

Using a wet finger or a soapy water solution,
check for a leak in the same areas.

If a leak is detected, remove the fan blade. In-
stall a new seal kit. See Group 20 of the

Heavy-

Duty Trucks Service Manual

for repair proce-

dures.

10. Check the fan drive for discoloration or any other

signs of slipping or overheating.

NOTE: The fan clutch may slip if the air supply
pressure is below 70 psi (483 kPa) or if there is
a leak inside the fan clutch. Any leak must be
remedied.

11. Check the fan clutch bearings.

11.1

Turn the fan in both directions and feel
for worn hub bearings.

11.2

If possible, remove the drive belt and
check for worn sheave bearings by turn-
ing the sheave in both directions.

f200581

05/30/2002

Fig. 9, Checking for Air Leaks (Horton DriveMaster)

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Heavy-Duty Trucks Maintenance Manual, January 2007

20/10

11.3

If either the hub or sheave bearings are
worn, replace them, using a Horton Drive-
Master Super Kit.

For instructions and kit part number, see
Group 20 of the

Heavy-Duty Trucks Ser-

vice Manual

Engine Cooling/Radiator

Heavy-Duty Trucks Maintenance Manual, January 2007

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