Crankshaft Rework Procedure for Certain 3508 Off-Highway Truck Engines{1202} Caterpillar

Off-Highway Truck/Tractor:

777D (S/N: FKR1-UP)

Introduction

Do not perform any procedure in this Special Instruction until you read this information and you understand this information.

This Special Instruction describes the procedure in order to rework the crankshaft for certain 3508 Off-Highway Truck Engines.

Crankshaft Rework Procedure

Note: Any dealership attempting this repair must have crankshaft balancing equipment or have access to crankshaft balancing equipment.

Note: Ensure all the counterweights are marked for location and orientation prior to disassembly. Refer to Reuse and Salvage Guidelines, SEBF8156, "Procedure to Inspect Crankshafts in 3500 Family of Engines" for the counterweight marking procedure.

1. Confirm the reusability of the crankshaft. Refer to Reuse and Salvage Guidelines, SEBF8039, "Crankshaft Visual Inspection and Magnetic Particle Inspection"

   Note: There is no need to continue on with the salvage process on a crankshaft that cannot be reused.

2. Remove the six counterweights from the crankshaft.

3. Discard all but two of the counterweight bolts. Two of the counterweight bolts will be needed in Step 5 to attach the gage to the crankshaft.

4. If each side of the crankshaft pad corner clearance to the counterweight fillet does not meet 5 mm (0.197 inch) on counterweights 1 and 8, or 4 mm (0.157 inch) on all other counterweights, or if unacceptable fretting has occurred, replace the counterweight. Refer to Reuse and Salvage Guidelines, SEBF8156 for more information on unacceptable fretting.

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Illustration 1	g03594576
(1) Gage

5. Attach gage (1) finger tight to the crankshaft using the counterweight bolts.

   Note: The dealer needs to fabricate the gage, refer to ""Gage Prints" " for more information on building the gage.

6. Apply Dykem to the material not covered by gage (1) or scribe a line along the edge of gage (1) if there is excess width material.

   If the material extends past the pad, possible damage to the counterweight can occur. Counterweights from pads that fail the gage test must be scrapped.

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Illustration 2	g03594578
(2) Tape

7. Cover all the crankshaft journals with tape (2) .

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Illustration 3	g03594579
Typical crankshaft without chamfer. (3) Scribed line

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Illustration 4	g03594580
Typical crankshaft with chamfer. (3) Scribed line (4) Chamfered edge

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Illustration 5	g03594878
Typical crankshaft chamfered with an end mill. (5) End mill

8. Machine a 45 degree chamfer along scribed line (3) with an end mill (5). Use a milling machine, a machining center, or handheld grinder.

   Note: In most cases, the crankshaft will only need one end of the counterweight pad milled.

   The preferred method is a milling machine or machining center.

   Note: Take care to ensure that overheating of the surface does not occur, as bluing will destroy the hardness of the crank.

9. Clean off abutment faces after de-burring.

10. Remove the protective tape from the crankshaft journals and clean the crankshaft.

11. Attach the counterweights using new bolts. Refer to Reuse and Salvage Guidelines, SEBF8156 for more information on installing the counterweights.

12. If any counterweights are replaced, then the crankshaft must be balanced. Refer to Reuse and Salvage Guidelines, SEBF8042 for more information on balancing the crankshaft.

13. Wash all debris off the crankshaft.

14. Inspect the crankshaft according to the Reuse and Salvage Guidelines, SEBF8039. If further machining or polishing is required, refer to Reuse and Salvage Guidelines, SEBF8042.

Oil Plug Torque Check

1. Start the torque check by putting a paint line across the oil plug and crankshaft. This line will give a visual indication on the completion of this process if torque was not correct.

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Illustration 6	g03680824
(1) 2W-2288 Plug

2. Check the torque of each oil plug (1) .

   Torque oil plug ... 35 N·m (26 lb ft)

3. If set torque is achieved without plug rotation, the oil plug has received the correct torque. Continue to the next oil plug until all oil plugs are checked.

4. If the set torque has not been achieved and there is oil plug rotation, the oil plug does not have the correct torque. Take a photo of the lines across the oil plugs which have changed position relative to the journals.

5. Record the findings of all the oil plugs.

6. If any loose oil plugs are found, remove all the oil plugs from the crankshaft and inspect the thread formation of the crankshaft and oil plug.

7. Inspect all the oil plug mounting threads by using a 5/8-18-2BUNF thread gage.
   • If any damaged threads are noticed or the thread plug gage is unable to insert, retap the oil hole by using a 5/8-18-2BUNF tap. Then try to insert the thread gage again.

   • If the oversize gage side fits after turn five, discard the used plug. Apply an even layer of Loctite 620 around the entire threads of the new 2W-2288 Plug . Torque the new plug to 50 ± 7 N·m (37 ± 5 lb ft).

   Note: Allow the Loctite to cure for a full 24 hours.

Gage Prints

Illustration 7	g03631456
(A) 16.459 ± 0.051 mm (0.648 ± 0.002 inch) (B) 141.4399 mm (5.5685 inch) (C) 29.997 ± 0.102 mm (1.181 ± 0.004 inch) (D) 168.910 ± 0.051 mm (6.650 ± 0.002 inch) (E) 22.022 ± 0.025 mm (0.867 ± 0.001 inch) thru x 2 (F) 27.559 mm (1.085 inch) (G) 15.011 mm (0.591 inch) (H) 12.700 mm (0.500 inch)

Note: Break all edges a minimum of 0.76 mm (0.03 inch).

Illustration 8	g03638116
(J) 13.21 mm (0.52 inch) (K) 44.45 mm (1.75 inch) (L) 63.50 mm (2.50 inch) (M) 6.35 mm (0.25 inch) (N) 3.30 mm (0.13 inch)