The Series 50 air compressor is flange mounted to the air compressor drive assembly, located on the left side of the engine at the rear of the gear case. See Figure 20544 .
Air Compressor Mounting
Detroit Diesel has improved the mounting of the air compressor coolant inlet hose which runs from the cylinder block to the air compressor. The improved mounting eliminates the potential for air compressor coolant hose abrasion caused by rubbing against the cylinder block.
To eliminate abrasion caused by rubbing of the coolant inlet hose against the cylinder block, a new mounting clip (23506443) and bolt (11503454) are now used on all engines with Bendix air compressors.
Original air compressors were flange-mounted to the air compressor drive assembly. See Figure 25213 . Effective with unit serial number 4R6959 built November 22, 1994, adaptorless air compressors replaced the original compressors on the majority of Series 50 engines. Adaptorless compressors are flange-mounted directly to the gear case. See Figure 24590 . Improved cylinder blocks were released concurrent with this change. The adaptorless air compressors can only be used with the improved cylinder blocks. Refer to Section for information on the improved cylinder blocks.
Adaptorless Air Compressor Mounting
Location of Air Compressor Pressure Relief Valve
This air compressor also drives the engine fuel pump which is bolted to the rear end of the compressor. The compressor crankshaft is designed to accept a drive coupling placed between the compressor and fuel pump.
The compressor is driven by the bull gear. The air compressor is water cooled. Engine coolant is fed to the compressor through a flexible hose tapped into the engine block water jacket and connected to the front of the compressor. Coolant returns from the rear of the compressor through a flexible hose to the engine cylinder head. Lubricating oil is supplied to the compressor by a line from the cylinder block oil gallery that connects to the air compressor. Lubricating oil returns to the engine crankcase through the air compressor drive assembly. The Series 50 air compressor is unique compared to the DDC two cycle engines because of its special forged crankshaft, drive hub, and nut.
Detroit Diesel does not service the air compressor. Service of air compressors should be referred to an authorized service center of the original equipment manufacturer.
To replace the air compressor, perform the following procedure. See Figure 21744 .
Flowchart for Replacement of Air Compressor
Pre-cleaning is not necessary.
Remove the air compressor as follow:
Note: Due to the cylinder block and compressor configuration, the upper inside air compressor-to-air compressor drive bolt is difficult to reach with standard tools. Compressor wrench, J 35948 , will facilitate removal and installation of this bolt.
Refer to OEM guidelines to determine if the air compressor needs to be repaired or replaced.
Install the air compressor as follows:
Note: The shorter bolt is installed in the two o'clock position.
Bolt Torque Sequence