2000/04/01 Caterpillar

Truck Engines:

3306B (S/N: 63Z23466-UP)

3306C (S/N: 2AZ199-UP; 7RJ6046-UP; 9TL22886-UP)

Truck Engine News SEBD6722-00, April 2000, "New Water Pump Group (Basic) Includes Many Improvements". Disregard this article. See the replacement article that follows:

Description of Change: New water pump groups with many improvements are used on 3306B and 3306C Truck Engines. These improvements include the following items:

• Cast iron impeller with low inertia

• Stainless steel shaft that is resistant to corrosion

• A straight press fit between the impeller and the shaft that helps to prevent the components from becoming loose

• A water seal that is made as a single piece for improved fluid sealing

• An oil seal with a dual lip for improved fluid sealing

• Improved gasket between the pump housing and the cover

• Redesigned water pump housing that provides reduced inlet restrictions

• The water pump housing is redesigned in order to include a reservoir type weep hole. This design allows any small coolant drip that gets past the water seal to evaporate.

Adaptable To: The new water pump groups and the former water pump groups are identified in Tables 1 through 3. The new water pump groups are available, as shown.

Table 1

Spur Gear Configuration
New Water Pump Group	Former Water Pump Group	Water Pump Group
172-7760	155-0061	4P-9861
172-7763	155-0064	118-9728
172-7765	155-0066	116-7556

Table 2

Helical Gear Configuration 7/16 Gear Retaining Bolt
New Water Pump Group	Former Water Pump Group	Water Pump Group
172-7759	155-0060	7C-3633
172-7766	155-0067	7N-5908
172-7767	155-0068	7N-5909

Table 3

Helical Gear Configuration Service Replacement 3/8 Gear Retaining Bolt
New Water Pump Group	Former Water Pump Group
172-7775	2P-0661
172-7776	2P-0662
172-7780	7N-2510

The following parts books need to be updated:

• Parts Manual, SEBP2182, "3306B Truck Engine (63Z)"

• Parts Manual, SEBP2750, "3306C Truck Engine (2AZ)"

• Parts Manual, SEBP1990, "3306C Truck Engine (7RJ)"

• Parts Manual, SEBP2269, "3306B Truck Engine (9TL)"

Illustration 1	g00687466
(A) 7N-0200 Gasket (Water Outlet) (B) 2P-0406 Gasket (Water Outlet)

There are two different shaft lengths that are available for the new pump:

• 74.4 mm (2.93 inch)

• 80 mm (3.15 inch)

The longer 172-5185 Water Pump Shaft is used on pumps which use (A) 7N-0200 Gasket (Water Outlet). The shorter 172-5188 Water Pump Shaft is used on pumps which use (B) 2P-0406 Gasket (Water Outlet).

Note: When the impeller is pressed onto the shaft, a face clearance of 0.65 to 0.9 mm (0.025 to 0.035 inch) must be obtained. The face clearance is measured between the top of the impeller vanes and the water pump housing. The new shafts are ground on the end in order to produce a highly accurate shaft length. This will allow a depth dimension to be made from the back of the impeller to the 4 bolt flange of the water pump housing and the desired face clearance will be produced. The depth dimension will be dependent on the pump that is being used. The new pumps have a depth dimension of 0.800 ± 0.314 mm (0.032 ± 0.012 inch). The parts service pumps have a depth dimension of 0.254 ± 0.064 mm (0.010 ± 0.003 inch). This dimension should be obtained if the impeller is pressed onto the shaft that is shown in Illustration 2.

Illustration 2	g00687553
(C) The hub of the impeller is flush with the shaft. (D) The outer diameter of the impeller is flush with the shaft. (1) Water Pump Shaft (2) Pump Impeller (3) Water Pump Shaft (4) Pump Impeller

There are two water pump seals and three new impellers that are available. Two items must be known in order to select the correct water pump seal and the new impeller. The first selection criteria is the water outlet gasket that is mentioned above. If the 2P-0406 Gasket (water outlet) (B) is used, then the 172-6712 Pump Impeller with the short vane height is used. If the 7N-0200 Gasket (water outlet) (A) is used, then one of two impellers will be used. Measure the diameter of the seal bore in the water pump housing. If the bore measures 40.0 mm (1.58 inch), then the 172-5189 Pump Impeller (2) is used with the one-piece 169-1750 Seal Gp. The impeller (2) will be pressed on the shaft (1), until the impeller is flush with the end of the shaft (C). If the bore measures 32.7 mm (1.29 inch), then the 172-5190 Pump Impeller (1) is used with the two-piece 4W-3864 Seal Gp. The 172-5189 Pump Impeller and the 172-5190 Pump Impeller use the same same vane height, but the 172-5190 Pump Impeller has a counterbore for the two-piece seal. This counterbore has a diameter of 32.5 mm (1.28 inch) and a depth of 6.2 mm (0.24 inch). Both of the impellers (4) will be pressed on the shaft (3), until the diameter of the impeller is flush with the end of the shaft (D). Use 172-5711 Installer (Seal) in order to install the one-piece 169-1750 Seal Group .

An alternate method can be used to check the position of the impeller on the shaft. Press the impeller onto the shaft, while the clearance is checked at intervals. The clearance is checked between the impeller and the water pump housing. Use a feeler gauge to check the clearance between the impeller and the water pump housing. The clearance should be 0.64 mm (0.025 inch).

The 8C-5210 Lip Seal is used on water pumps with a two-piece water pump seal. The 154-4482 Seal is used on water pumps with a one-piece water pump seal. On both of the seals, the "cup" is installed toward the center of the housing and the lip of the seal is NOT lubricated.

Rebuild kits are available and the proper rebuild kit can be identified in Table 4.

Note: The 172-5185 Water Pump Shaft is included in all rebuild kits. The "Early" pumps that require the shorter 172-5188 Water Pump Shaft should not use any of these rebuild kits. When a water pump is rebuilt and the 172-5190 Pump Impeller and a kit are used, a 4W-3864 Seal Gp needs to be ordered.

Table 4

Available Rebuild Kits
Rebuild Kit Part Number	Applicable Water Pump Group
170-0567	172-7759	172-7760
	172-7763	172-7766
170-0570	172-7765	172-7767

The proper rebuild kit is determined by the outer bearing that is used on the pump. If the outer bearing has a diameter of 80 mm (3.15 inch), use a 170-0567 Water Pump Kit. If the outer bearing has a diameter of 72 mm (2.83 inch), use a 170-0570 Water Pump Kit. If the outer bearing has a diameter of 62 mm (2.44 inch), use a 170-0569 Water Pump Kit. These kits include the following items:

• Inner bearing

• Outer bearing

• Latest 172-0038 Gasket

• 154-4482 Seal

• One-piece 169-1750 Seal Group

• Some miscellaneous pieces

The following two gasket kits are available when the pump is replaced as a unit:

• The 171-3686 Gasket Kit

• The 170-1834 Gasket Kit

The 171-3686 Gasket Kit is for the pumps that use (A) 7N-0200 Gasket (Water Outlet). The 170-1834 Gasket Kit is for the pumps that use (B) 2P-0406 Gasket (Water Outlet).

Remanufactured water pumps are available and the proper remanufactured water pump can be identified in Table 5.

Note: Remanufactured water pumps are recommended instead of rebuilding.

Table 5

Available Remanufactured Water Pumps
Remanufactured Water Pump Part Number	Applicable Water Pump Group
0R-9782	172-7759
0R-9783	172-7760
0R-9784	172-7764
0R-9785	172-7765
0R-9786	172-7766
0R-9787	172-7767