Usage:
The fan is driven by three V-belts from a pulley on the crankshaft. The belts and pulleys should be kept clean of any accumulations of dirt and grease to prevent belt slippage which would result in short belt and pulley life and engine overheating.
Fan Belt Replacement
PREPARING TO REMOVE FAN BELTS (D398 and D379 Illustrated)
1-Bolt (four). 2-Fan guards (four).
1. Loosen the bolts (1) which hold the fan mounting bracket to the front accessory drive housing.
REMOVING FAN BELTS
3-Fan belts (three.)
2. Loosen the locknut and back off the adjusting screw to allow the fan hub to move to its lowest position.
3. Remove the fan belts (3) from the lower pulley and then over the fan blades as shown.
NOTE: It is necessary to rotate the fan when removing the belts.
NOTE: Inspect the belts for wear or damage. If any one of the belts needs replacing, install a new set. Always install a matched set of belts, never only one.
4. Adjust the fan belt tension. See the topic, FAN BELT ADJUSTMENT.
Fan And Hub
Removal and Installation
PREPARING TO REMOVE FAN AND HUB (D398 and D379 Illustrated)
1-Bolt (four). 2-Fan guards (four).
1. Loosen the bolts (1) which hold the fan mounting bracket to the front accessory drive housing.
2. Loosen the locknut and back off the adjusting screw to allow the fan hub to move to its lowest position.
3. Remove the fan belts (4) from the lower drive pulley.
4. Attach a suitable hoist and sling around the fan hub.
5. Remove the bolts (1) holding the fan mounting bracket to the front accessory drive housing and lift out the fan drive group.
6. Inspect all parts for wear or damage and replace if necessary.
REMOVING FAN AND HUB
3-Fan drive group. 4-Fan belts (three).
Disassembly and Assembly
1 Fan.
2 Bearing.
3 Hub.
4 Seal.
5 Bolt (eight).
6 Bolt (four).
7 Retainer.
8 Cover.
9 Spacer.
10 Spacer.
11 Spacer.
12 Spacer.
13 Shaft.
14 Bearing.
DISASSEMBLING FAN DRIVE (CROSS SECTION)
Use a suitable puller to remove the bearing (2) and hub (3) from the shaft (13).
Inspect all parts for wear or damage and replace if necessary.
NOTE: When installing the seal (4), lubricate the lip of the seal with lubricant being sealed to facilitate installation without damage to the seal. Install the seal with the lip facing away from the bearing.
Fan Belt Adjustment
The fan belts should be checked periodically for proper adjustment. If the fan belts are operated too loose, they will slip on the pulleys causing unnecessary wear to the belts and possibly slipping to the extent that the engine will overheat. If the belts are too tight, unnecessary stresses are placed upon the fan bearings and belts which might shorten the life of both.
Correct adjustment exists when the belts can be pushed inward .56-.82 in. (14,2-20,8 mm) with approximately 25 lbs. (11,3 kg) force exerted midway between the two pulleys.
Introduction
The fresh water pump is mounted on the rear side of the upper drive of the accessory drive housing on the right side of the engine. The pump is gear driven and receives lubrication from the engine lubrication system.
WATER PUMP CROSS SECTION
1-Gaskets. 2-Water seal. 3-Pump housing. 4-Bearing retainer. 5-Drive gear. 6-Thrust bearing. 7-Shaft. 8-Inlet cover. 9-Impeller. 10-Seal assembly. 11-Thrower. 12-Oil seal. 13-Bearing.
Correct impeller end clearance is obtained by the amount of gaskets (1) between pump housing (3) and inlet cover (8). End thrust is taken by thrust bearing (6).
The replaceable carbon washer in water seal (2), held against the face of seal assembly (10), prevents coolant from escaping. In case the seal leaks, a drain opening under pump housing (3) allows any coolant leakage to escape. Thrower (11), machined in the shaft on later engines, prevents escape coolant from entering the lubricating system through oil seal (12).
Removal And Installation
1. Drain the cooling system including the water pump.
2. Disconnect the cooling system supply line from the water pump inlet elbow.
3 Remove oil cooler supply tube (1).
4. Remove alternator or generator (4), if so equipped.
5. Loosen the drive pulley retaining nut (6) and remove pulley (7) with 8H695 Puller and 8B7560 Step Plate. At assembly, tighten the pulley retaining nut to torque of 100 lb. ft. (13,8 mkg).
NOTE: Replace the seal and the bearing in bearing retainer (8) if damaged. When replacing the bearing, align the bearing oil hole with the groove in bearing retainer (8). Install the seal with the lip facing the bearing.
PREPARING TO REMOVE WATER PUMP (D399 Engine Illustrated)
1-Oil tube assembly. 2-Exhaust manifold. 3-Water bypass tube. 4-Alternator or generator. 5-Pipe and elbow.
REMOVING BEARING RETAINER
6-Pulley retaining nut. 7-Drive pulley. 8-Bearing retainer.
6. Attach a suitable hoist and remove six bolts which secure the water pump to the front accessory drive housing. The pump weighs approximately 35 lbs. (39 kg).
7. Remove the water pump assembly as illustrated.
REMOVING WATER PUMP
9-Water pump.
Disassembly And Assembly
1. Remove the inlet elbow and cover from the water pump.
REMOVING IMPELLER
1-Impeller. 2-Centering spacer. 3-Puller. 4-Bolts (two).
NOTE: Inspect the O-ring seal in the inlet cover and replace if damaged.
2. Insert two 5/16" NC bolts (4) 2" long into the threaded holes in impeller (1).
3. Remove the impeller with 8H700 Puller (3) and T774 Centering Spacer (2).
NOTE: Carefully remove the impeller to prevent damage to the impeller seal assembly. The seal assembly can adhere to either the impeller or the pump shaft (10).
REMOVING SHAFT ASSEMBLY
5-Bolts (six). 6-Thrust bearing. 7-Bearing retainer. 8-Pump housing. 9-Drive gear. 10-Shaft.
4. Loosen bolts (5) which secure thrust bearing (6) and bearing retainer (7) to pump housing (8). Remove the shaft.
NOTE: Replace oil seal (11) and bearing (12) if damaged. Install oil seal (11) with the lip facing bearing (12).
DISASSEMBLING BEARING RETAINER
7-Bearing retainer. 11-Oil seal. 12-Bearing.
CHECKING IMPELLER END CLEARANCE
13-Thickness gauge. 14-Inlet cover. 15-Gaskets.
5. Check the impeller-to-cover clearance by using thickness gauge (13) inserted between the impeller and inlet cover (14) as shown in the illustration. The correct clearance is .005-.020 in. (0,13-0,50 mm). The amount of gaskets (15) regulate this clearance.
NOTE: Tighten impeller retaining nut to torque of 55 lb. ft. (7.6 mkg).
Water Pump Seal And Oil Seal Replacement
Water draining from the under side of the pump indicates a damaged water seal (either bellows seal assembly or impeller seal assembly or both).
NOTE: It is not necessary to remove the water pump from the water pump housing for seal replacement.
Remove the impeller as described in the topic WATER PUMP DISASSEMBLY AND ASSEMBLY.
The seal consists of a carbon thrust washer (3) and a spring enclosed by bellows (2). These two parts which make up the replaceable unit are contained in a brass case (1), which is pressed into the water pump housing.
BELLOWS SEAL ASSEMBLY
1-Case. 2-Bellows. 3-Carbon thrust washer.
Inspect the contact surfaces of both carbon thrust washer (3) and the face of the impeller seal assembly. Both contact surfaces must be smooth and free of nicks or scratches. Replace if damaged.
The impeller seal assembly can be removed after the impeller is removed.
It is not necessary to remove the brass case (1) from the water pump housing for seal replacement. The carbon thrust washer (3) and the bellows (2) can be removed from the case by bending back the three ears (4) which hold them in place.
WATER SEAL
1-Case. 3-Carbon thrust washer. 4-Ears (three).
When replacing the carbon thrust washer, be careful not to crack or scratch it. After the bellows seal and thrust washer are installed, see that the washer moves freely under finger pressure.
If the brass case is damaged, cup extractor (5) of the FT200 Fabricated Tool can be used for removing it. If a tool is not used, it is necessary to completely disassemble the pump to replace the brass case.
SEAL CASE REMOVAL
5-Cup extractor.
When installing a new brass case, coat the case and housing bore with 7M7456 Sealant to avoid shearing the brass case, and to provide a positive seal against water leakage.
Make sure the case bottoms squarely in the bore so the carbon washer will bear evenly against the impeller contact surface.
| NOTICE |
|---|
Applying excess pressure after the case bottoms will bend the flange on the case. |
Install the impeller seal assembly with the smooth face of ring (A) toward the carbon washer of the bellows seal assembly. The grooved side of the ring faces the rubber seal (B).
IMPELLER SEAL ASSEMBLY
A-Rings. B-Rubber seal.
If it becomes necessary to replace the oil seal, the pump must be disassembled.
Press the old seal out and install a new one, with the lip of the seal toward the bearing.