2015/05/29 Caterpillar

Engine:

All 3600

All C280

All G3600

Extensive testing has shown that some tooling can introduce additional stress in the rod bolt during the final turn of the rod bolt torque process. Caterpillar recommends the use of a hydraulic wrench reacting off the rod weight boss, or an impact wrench while performing the final turn portion of the rod bolt torque process to reduce the additional stresses. Caterpillar does not recommend the use of a Pneumatic gun with a reaction arm or breaker bar with an extension to perform the turn portion of the torque process.

In addition to using the proper tooling, Caterpillar recommends to reducing the 375 ± 15 N·m (277 ± 11 lb ft) torque value to 340 ± 15 N·m (250 ± 11 lb ft). Reducing the torque Value maintains the clamp load required for the rod joint, and provides additional margin due to tooling errors that can introduce additional bolt stress.

Reuse Information for the Connecting Rod Bolts

Illustration 1	g03743611
(1) 369-7183 Heat Shrink Tube (2) Annular Rings (3) 205-0640 Nut

Inspect connecting rod bolts at each service of the connecting rod bearings. There should be no fretting on the shank, knurled or annular ring area (2) of the connecting rod bolt. Ensure that the connecting rod bolt meets the guidelines for the reusable parts. Do not reuse the connecting rod nuts.

Prior to installation of the new 467-0537 Bolt As, inspect heat shrink tube (1). The tube serves as an alignment sleeve for the bolts.

• The heat shrink tube must be firmly in place and must not move under light finger pressure.

• The whole surface of the tube must be smooth.

• The tube must not extend into the fillet that is under the bolt head.

If a problem is found with the tube, use the following replacement procedure.

1. Carefully cut the heat shrink tube from the bolt.

2. Ensure that there is no damage to the shank of the bolt that was under the tube.

3. Clean the shank of the bolt with solvent in order to remove any oil or molylube.

4. Install a new 369-7183 Heat Shrink Tube onto the bolt. Position the tube approximately 1.5 mm (0.059 inch) under the bolt head, away from the fillet that is under the bolt head.

5. Use a heat gun or place the bolt and tube in an oven at 135° ± 14°C (275° ± 25°F) for 10 minutes. The tube must shrink into place without any bumps or wrinkles.

6. After the bolt cools, the tube must be firmly in place. The tube must not move under light finger pressure.

7. Make sure that the surface of the tube is smooth all around. Verify that the tube does not extend onto the fillet that is under the bolt head.

The 467-0537 Bolt As may be tightened for a maximum of five times. The reuse includes retightening after checking the rod bore or bearing clearance. Do not reuse the connecting rod nuts.

An overloaded bolt can be detected by threading a new 205-0640 Nut onto the bolt by hand. If the threads are not damaged, the nut will easily reach the end of the bolt thread with light finger pressure. If the nut stops before reaching the end, do not reuse the bolt.

Tightening Procedure for Connecting Rod Bolts

Illustration 2	g03743742
(1) 4W-8344 Retainer

1. Before the bolts are installed into the connecting rod, clean retainers (1). Clean the seats for the retainers on the connecting rod and the bolt heads. The parts must be clean and dry.

2. Inspect each bolt for debris, nicks, and for damage from shipping.

3. Assemble the retainers and the bolts into the connecting rod as shown in Illustration 2.

4. After the bolts have been installed, lubricate the threads of the bolts, threads of the nuts, and the seats for the nuts on the connecting rod with a heavy coat of 334-0519 Grease.

   Note: This torque procedure was developed with 334-0519 Grease. The use of any other lubricant may result in an incorrect torque value and in subsequent failure of the connecting rod bolt.

5. While holding the rod cap tight against the connecting rod, ensure that the connecting rod bolts are properly seated on the retainer. Turn all four nuts by hand until the nuts contact the face of the cap. No resistance should be felt that would indicate thread damage or debris in the joint. Thread the nuts by hand in order to identify problems with the threads. If the nuts and/or bolts cannot be threaded by hand, the nuts and/or bolts must be replaced. Ensure that the threaded end of the bolt is flush with the end of the nut. Checking ensures that the bolt head is properly seated on the retainer. Do not use an impact wrench to install the nuts up to the face of the cap.

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Illustration 3	g03743790
(5) Bearing Tab Slot (6) Serial Number Pad

Note: Understanding the locations of the bolts and using the exact tightening sequence is critical. Holes (1) and (4) are small then holes (2) and (3). The bolts in holes (1) and (4) are used to index the rod cap to the correct location on the rod. The bolts in holes (1) and (4) must be tightened first.

Note: Holes (1) and (2) are on the same side of the connecting road as the bearing tab slot (5). Hole (1) is on the side next to the serial number pad (6). The cylinder number is on the bearing tab side of the connecting rod.

Note: If the cap is allowed to separate once contact is made between the cap and rod, the rod bearing may become unseated. If the rod bearing becomes unseated, the bearing may be damaged when torque is applied.

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Illustration 4	g03743797

6. Using a calibrated click torque wrench, tighten nuts (1), (4), (2), and (3) in sequence to 105 ± 15 N·m (75 ± 10 lb ft).

7. Using a calibrated click torque wrench, tighten nuts (1), (4), (2), and (3) in sequence to 340 ± 15 N·m (250 ± 11 lb ft).

8. Without loosening the nuts, tighten the nuts for the second time in the following order (2), (3), (1), and (4) to 340 ± 15 N·m (250 ± 11 lb ft).

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Illustration 5	g03744818
Location for marking the rod, nut, and socket.

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Illustration 6	g03744829
Sample of the Caterpillar 384-8910 Hydraulic Wrench being used to do the 180 degree turn, showing the reaction arm reacting off the rod cap weight boss.

9. Mark the rod, nut, and the socket as shown is Illustration 5. Then using a hydraulic wrench or impact wrench, tighten the nuts again in the following order (1), (4), (2), and (3). Turn the nuts in a clockwise direction to 180 ± 5 degrees.

   Note: Extensive testing has shown that some tooling can introduce additional stress in the rod bolt during the final turn of the rod bolt torque process. Caterpillar recommends the use of a hydraulic wrench reacting off the rod weight boss, or an impact wrench while performing the final turn portion of the rod bolt torque process to reduce the additional stresses. Caterpillar does not recommend the use of a Pneumatic gun with a reaction arm or breaker bar with an extension to perform the turn portion of the torque process.

This new torque procedure is adaptable to all 3600, G3600and all C280 Engines. This procedure is not for 3618 Diesel Engines.