Usage:
C-10 (2PN, 8YS, 3CS1-1873),
C-12 (1YN, 9NS, 2KS1-3488) Truck Engines
Description of Change:
Illustration 1.
Nine new bolts and washers are being used to mount the rear power take-off flywheel housing group to the engine block joint in these truck engines. The new bolts are socket head bolts and are stronger than the former bolts. The new washers are larger in diameter and distributes the sealing pressure more evenly over the entire gasket. These changes will help prevent oil leaks at the joint between the rear power take-off flywheel housing and the engine block.
Adaptable To: The new 8T-0273 Bolts-Socket Head and the new 5P-1076 Washers are a direct replacement for the former 6V-8197 Bolts and the 5P-8245 Washers, used in the 117-2769 Gear Group. Illustration 1 shows the location of the nine new 8T-0273 Bolts-Socket Head and the nine new 5P-1076 Washers. The new bolts and washers are in effect with C-10 (3CS1-1873) and C-12 (2KS1-3488). The new components and repair procedures are adaptable to all earlier C-10 (2PN, 8YS) and C-1 (1YN, 9NS) Truck Engines.
Installation Procedure
When a repair is being made to an oil leak at the joint between the Rear Power Take-Off (RPTO) Flywheel Housing and the engine block, use the following procedures.
1. Remove the flywheel housing, check the flywheel housing to main bearing cap interference. If there is evidence of interference, this can cause an oil leak, between the engine block and the RPTO/Flywheel Housing.
Illustration 2.
Locations of the two notches in the Rear Power Take-Off/Flywheel Housing (D). Location of the dowel (E) and the center notch (F).
Illustration 3.
Notch Template at 1/2 scale.
A. Make a copy of the Notch Template in Illustration 3. Enlarge the copy of the Notch Template by 200%. The distance between the center notch and the dowel is 150 mm or 5.90 inch. Use the dimensions as a reference to ensure the correct size of the Notched Template. Cut the Notched Template out and place it face up on the block side of the the RPTO/Flywheel Housing using the center notch (F) and dowel (E) in Illustration 2 as guides. Trace the two notches on to the RPTO/Flywheel Housing. Grind the two notches in the RPTO/Flywheel Housing to a depth of 3.5 mm or 1/4 inch. Reinstall the RPTO/ Flywheel Housing using the recommended sealant and proper procedures for that engine.
2. At the nine positions labeled (B) in Illustration 1, visually check the spot face under the flywheel housing mounting bolts.
A. If there is evidence of housing material displaced under the washers, (e.g. grooves, indentations), the spot face must be resurfaced.
B. Resurface the spot face to a diameter of 32.0 ± 1.0 mm (1.26 ± .04 in). The thickness of the housing from the engine side surface to the spot face can not be reduced to less than 18.0 ± 0.5 mm (.71 ± .02 in).
3. Use 8T-7751 Surface Reconditioning Pads and a suitable liquid gasket remover to remove the hardened sealant from the rear of the engine block, and the front of the flywheel housing.
A. Do not use abrasive material that is less than 120 grit when cleaning the flywheel housing, this may cause damage to the sealing surface.
B. Do not use abrasive material that is less than 120 grit when cleaning the flywheel housing, this may cause damage to the sealing surface.
NOTE: Oil flow to the gears may be interrupted if the sealant gets past the O-ring, around the oil passage at location (A), in Illustration 1. If the sealant is applied across the entire bottom of the flange, uncured sealant may get into the engine oil.
4. Apply 1U-8846 Sealant to the engine side of the flywheel housing, in the cross-hatched area only. (See Illustration 1.)
The flywheel housing must be mounted on the engine block within 10 minutes, after application of the sealant.
5. Mount the flywheel housing on the engine block, using new 8T-0273 Bolts-Socket Head and 5P-1076 Washers, at the positions labeled (B) in Illustration 1.
A. If the flywheel housing is already equipped with 8T-0273 Bolt-Socket Head and 5P-1076 Washers at the nine positions, the socket head bolts and washers can be reused.
B. Reuse the three 8T-0273 Bolts-Socket Head and small 1T-0808 Washers in their original positions, under the PTO gears.
C. Tighten the twelve mounting bolts to a torque of 105 ± 20 N·m (75 ± 15 lb ft).