freightliner COLUMBIA CL112 Maintenance Manual page 49

20
4. Check the fan for bent, cracked, or damaged
blades. Replace if damaged. Check for adequate
clearance between the fan and other compo-
nents.
5. Check the fan belt for wear, tension, and align-
ment. Correct if necessary.
6. 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.
7. 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 fan clutch from a distance.
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 Columbia
for troubleshooting and repair procedures.
8. 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
Using a wet finger or a soapy water solution,
check for a leak in the same areas.
05/30/2002
Fig. 8, Checking for Air Leaks (Horton DriveMaster)
20/8
® Workshop Manual
Fig. 8.
f200581
Engine Cooling/Radiator
9. If a leak is detected, remove the fan blade. In-
stall a new seal kit. See Group 20 of the
Columbia ® Workshop 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.
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 Columbia
Manual .
Columbia Maintenance Manual, January 2007
® Workshop