3126B and 3126E On-highway Engines Caterpillar

Removal Procedure

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Do not disconnect the air lines until the air pressure in the system is at zero. If hose is disconnected under pressure it can cause personal injury.

1. Remove the air pressure from the air tank and drain the coolant from the cooling system.
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   Illustration 1	g00609682

2. Disconnect water hose (1) and water hose (3) from the air compressor.

3. Disconnect air hose (2) and oil hose (4) from the air compressor.

4. Install Tooling (A) and a proper lifting device to the air compressor. The weight of the air compressor is approximately 23 kg (51 lb).

5. Remove the mounting bracket for a Midland EL-740 air compressor by using the following procedure:
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   Illustration 2	g00609684

   1. Remove bolt (8) and the clip for the oil hose from the bracket for the air compressor.

   2. Remove two bolts (5) and bolt (6) that fastens the bracket for the air compressor to the cylinder block. Remove bolt (7) and the spacer between the air compressor and the bracket for the air compressor. Remove the bracket for the air compressor.

6. Remove the mounting bracket for a Bendix Tu-Flo 550 and Bendix Tu-Flo 750 air compressors by using the following procedure:
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   Illustration 3	g00705242
   Typical example

   1. Remove bolts (9) that fasten the mounting bracket to the air compressor.

   2. Remove bolts (10) that fasten the mounting bracket to the cylinder block. Remove the mounting bracket for the air compressor.
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   Illustration 4	g00705313

7. Remove bolts (11), air compressor (12), and the gasket from the timing gear housing.

Installation Procedure

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Illustration 5	g00705313

1. Install Tooling (A) and a proper lifting device to the air compressor. The weight of the air compressor is approximately 23 kg (51 lb).

2. Inspect the condition of the gasket. Replace the gasket, if necessary. Install the gasket between air compressor (12) and the timing gear housing.

3. Position air compressor (12) in the front housing. Ensure that the drive gear engages correctly with the gear in the front housing.

4. Apply 9S-3263 Thread Lock Compound to the threads of two bolts (11). Install two bolts (11). Tighten bolts (11) to a torque of 100 ± 20 N·m (75 ± 15 lb ft).

5. Install the mounting bracket for a Midland EL-740 air compressor by using the following procedure:
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   Illustration 6	g00609684

   1. Position the bracket for the air compressor and install bolts (5) and (6). Install the spacer and bolt (7). Hand tighten all bolts.
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      NOTICE
      A loose compressor bracket can lead to a broken front cover and can cause damage to the front gear train of the engine.

   2. Tighten bolt (7) to a torque of 50 ± 10 N·m (37 ± 7 lb ft). Tighten bolt (5) to a torque of 55 ± 10 N·m (40 ± 7 lb ft). Tighten bolt (6) to a torque of 28 ± 7 N·m (21 ± 5 lb ft). Remove the lifting device and Tool (A).

6. Install the mounting bracket for Bendix Tu-Flo 550 and Bendix Tu-Flo 750 air compressors by using the following procedure:
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   Illustration 7	g00705242
   Typical example

   1. Position the bracket for the air compressor and install bolts (9) and bolts (10) finger tight.
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      NOTICE
      A loose compressor bracket can lead to a broken front cover and can cause damage to the front gear train of the engine.

   2. Tighten bolts (9) to a torque of 55 ± 10 N·m (40 ± 7 lb ft). Tighten bolts (10) to a torque of 55 ± 10 N·m (40 ± 7 lb ft). Remove the lifting device and Tooling (A).
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   Illustration 8	g00609682

7. Connect oil hose assembly (4) to the air compressor. Connect the clip that holds the hose assembly to the air compressor. Tighten bolt (8) that holds the clip to a torque of 28 ± 7 N·m (21 ± 5 lb ft).

8. Connect water hose (1) and (3) to the air compressor.

9. Connect air hose (2) to the air compressor.

10. Fill the cooling system with coolant to the correct level. Refer to the Operation and Maintenance Manual for the correct filling procedure.