2007/12/03 Caterpillar

Off-Highway Truck:

797 (S/N: 5YW1-UP)

797B (S/N: JSM1-UP)

Description of Change: Two elbow assemblies have been updated in the exhaust pipe groups. The two elbow assemblies have updated flanges that now match the flanges that are on the muffler assemblies. The updated flanges will improve the clamping force of the clamps that are applied to the joints that are between the elbow assemblies and the mufflers. This will minimize exhaust leaks at the joints and the wear at the joints.

Adaptable To: The updated 174-6325 Elbow As and the updated 247-4178 Elbow As are now part of the 149-3079 Exhaust Pipe Gp. This is the arrangement for the standard machines. The new parts are adaptable back to the beginning of production of the machines.

The updated 253-6176 Elbow As and the updated 253-6177 Elbow As are now part of the 172-4336 Exhaust Pipe Gp. This is the high altitude arrangement for the machines. The new parts are adaptable back to the beginning of production of the machines.

Both sets of updated elbow assemblies became effective in production with the machine JSM306-UP. Use the following procedures in order to install the updated elbow assemblies onto earlier machines.

Installation of the Updated Elbow Assemblies on Standard Machines

Show/hide table



Illustration 1	g01413299

Show/hide table



Illustration 2	g01413304

1. Remove the two 7E-8452 Clamps (6) from the 247-4178 Elbow As (4) and the 174-6325 Elbow As (5) .

2. Remove the 188-1072 Clamp (11) from the 174-6325 Elbow As (5) .

3. Remove the 233-7711 Heat Shield (8) from the 247-4178 Elbow As (4) .

4. Remove the 241-8492 Band Clamp (15) from the 247-4178 Elbow As (4) .

5. Remove the two 8T-4139 Bolts (13), the two 8T-4244 Nuts (14) and the four 5P-1076 Hard Washer (12) from the two elbow assemblies.

6. Remove the six 8T-4192 Bolts (9), the six 8T-4223 Hard Washers (10) and the two 154-6351 Straps (7) from the elbow assemblies.

7. With a suitable lifting device, remove the 247-4178 Elbow As (4) and the 174-6325 Elbow As (5) from the machine.

8. Inspect the flange faces and the tubes on the end of the mufflers that are toward the elbow assemblies for damage. If you find damage to the flange faces or the tubes of the mufflers, replace the mufflers.

9. By using a suitable lifting device, install the updated 174-6325 Elbow As (2). Secure the elbow assembly with the 188-1072 Clamp (11) that was removed in Step 2. Leave the clamp loose so you can adjust the parts. Install the new 7E-8452 Clamp (3) to the elbow assembly. Leave the clamp loose so you can adjust the parts.

10. By using a suitable lifting device, install the updated 247-4178 Elbow As (1) to the bellows assembly. Secure the elbow assembly with the 241-8492 Band Clamp (15) that was removed in Step 4. Leave the clamp loose so you can adjust the parts. Install the new 7E-8452 Clamps (3) to the elbow assembly and the muffler assembly. Leave the clamp loose so you can adjust the parts.

11. Install the two 8T-4139 Bolts (13), the two 8T-4244 Nuts (14) and the four 5P-1076 Hard Washers (12) that were removed in Step 5 to the two elbow assemblies.

12. Install the six 8T-4192 Bolts (9), the six 8T-4223 Hard Washers (10) and the two 154-6351 Straps (7) that were removed in Step 4 to the bracket on the frame in order to secure the elbow assemblies.

13. Tighten the 241-8492 Band Clamp (15) to 11 N·m (97 lb in).

14. Tighten the two 7E-8452 Clamps (3) and the one 188-1072 Clamp (11) to 16 ± 4 N·m (12 ± 3 lb ft). Tap lightly around the circumference of the three clamps. Then, tighten the three clamps to 16 ± 4 N·m (12 ± 3 lb ft).

    Note: The static inspection torque should be no less than 9 N·m (80 lb in).

15. Install the 233-7711 Heat Shield (8) that was removed in Step 3 to the updated 247-4178 Elbow As (1) .

Installation of the Updated Elbow Assemblies on Machines with the High Altitude Arrangement

Illustration 3	g01413472

Illustration 4	g01413474

1. Remove the two 7E-8452 Clamps (6) from the 253-6176 Elbow As (4) and the 253-6177 Elbow As (5) .

2. Remove the 233-7711 Heat Shield (10) and the 241-8492 Band Clamp (11) from the 253-6176 Elbow As (4) .

3. Remove the 233-7711 Heat Shield (10) and the 241-8492 Band Clamp (11) from the 253-6177 Elbow As (5) .

4. Remove the six 8T-4192 Bolts (8), the six 8T-4223 Hard Washers (9) and the two 154-6351 Straps (7) from the elbow assemblies.

5. With a suitable lifting device, remove the 253-6176 Elbow As (4) and the 253-6177 Elbow As (5) from the machine.

6. Inspect the flange faces and the tubes on the end of the mufflers that are toward the elbow assemblies for damage. If you find damage to the flange faces or the tubes of the mufflers, replace the mufflers.

7. By using a suitable lifting device, install the updated 253-6176 Elbow As (1). Secure the elbow assembly with the 241-8492 Clamp (11) that was removed in Step 2. Leave the clamp loose so you can adjust the parts. Install one new 7E-8452 Clamp (3) to the elbow assembly and the muffler assembly. Leave the clamp loose so you can adjust the parts.

8. By using a suitable lifting device, install the updated 253-6177 Elbow As (2) to the rear exhaust tube. Secure the elbow assembly with the 241-8492 Band Clamp that was removed in Step 3. Leave the clamp loose so you can adjust the parts. Install one new 7E-8452 Clamp (3) to the elbow assembly and the muffler assembly. Leave the clamp loose so you can adjust the parts.

9. Tighten the 241-8492 Band Clamp (11) to 11 N·m (97 lb in).

10. Tighten the two 7E-8452 Clamps (3) to 16 ± 4 N·m (12 ± 3 lb ft). Tap lightly around the circumference of the two clamps. Then, tighten the three clamps to 16 ± 4 N·m (12 ± 3 lb ft).

    Note: The static inspection torque should be no less than 9 N·m (80 lb in).

11. Install the two 233-7711 Heat Shields (10) that were removed in Step 2 and Step 3 to the updated 253-6176 Elbow As (1) and to the 253-6177 Elbow As (2) .