Usage:
Caterpillar Machines Powered By 3408 And 3412 Engines
Reference: Service Magazine; November 25, 1996; Page 13; "Procedure For Installing Steel Core Gasket At The Front Housing And The Flywheel Housing".
Description of Change: The flywheel housing to cylinder block joint uses a gasket to improve the integrity of the joint. The new gaskets are a steel core composite design with beading between the upper bolt holes to increase gasket loading in the tongue area of the housing.
One flywheel housing has changed from aluminum to cast iron.
Adaptable To: The new 109-4318 Gasket replaces the former 7N-9331 Gasket and the new 113-1474 Gasket replaces the former 8N-1911 Gasket in the flywheel housing groups in these engines. The former gaskets are canceled. Some engines that were built with 1U-8846 Liquid Gasket, between the cylinder block and flywheel housing, can be serviced with the new gaskets. See the chart for effectivity of the new gaskets.
NOTE: Due to heavy load factors, do NOT use the new gaskets in the 990 and 988F Wheel Loaders. Continue to use the 1U-8846 Liquid Gasket.
The new 113-1992 Flywheel Housing (cast iron) replaces the former 4P-8534 Flywheel Housing (aluminum).
Installation Of New Steel Core Flywheel Housing Gaskets
Before installing the gasket, existing sealant must be removed from the mating surfaces of the flywheel housing and cylinder block with 4C-4188 Paint Remover. Do not use a steel brush or rotary "Scotch Brite" pad to clean the surfaces. These may damage the contact surfaces. The previous gasket extended below the pan mounting surface and filled the entire block to flywheel housing joint. The 109-4318 and 113-1474 Flywheel Housing Gaskets with the steel core cannot be trimmed after assembly and is flush to recessed at the "Tee" joint between the block, flywheel housing, and oil pan. Seal the area not occupied with gasket material with 8T-9022 RTV Sealant (BLUE). This sealant is compatible with the gasket material. (For more complete instructions, see the Reference Article).
Using the new 109-4318 or 113-1474 Flywheel Housing Gaskets on a flywheel housing originally designed for use with sealant may require elongation of the bolt holes in the pan, oil pan gasket, and stiffener plate (if equipped). The gasket is approximately 0.76 mm (.030 in) thick. Before engine operation, check the clearance between the flywheel housing and rear gear train and flywheel. Push the crankshaft towards the front of the engine when checking the flywheel to flywheel housing clearance. Flywheel housings designed for gaskets have a 16.76 mm (.660 in) dimension from the flywheel housing to the centerline of the oil pan mounting bolts. Flywheel housings designed for sealant have a 17.46 mm (0.688 in) dimension from the flywheel housing mounting face to the centerline of the oil pan mounting bolts. These housings are usually marked with the note "CAUTION: USE ONLY LIQUID GASKET ON BLOCK JOINT" on the inside of the housing.
Bolt Tightening Procedure For "20 Bolt" Flywheel Housings
Bolt identification for "20 Bolt" flywheel housings.
1. Tighten bolts 1 through 20 in numerical sequence to a torque of 40 ± 10 N·m (30 ± 7 lb ft).
2. Tighten bolts 1 through 8 in numerical sequence to a torque of 135 ± 20 N·m (100 ± 15 lb ft).
3. Tighten bolts 9 through 20 in numerical sequence to a torque of 55 ± 10 N·m (40 ± 7 lb ft).