BENDIX BA-921

FIGURE 1 - BA-921 COMPRESSOR
DESCRIPTION
The function of the air compressor is to provide and main-
tain air under pressure to operate devices in the air brake
and/or auxiliary air systems. The BA-921 compressor is a
single cylinder reciprocating compressor with a rated dis-
placement of 15.8 cubic feet per minute at 1250 RPM.
The compressor consists of a water cooled cylinder head
and valve plate assembly and an air cooled integral
crankcase and cylinder block. The cylinder head is an
aluminum casting which contains the required air and water
ports as well as an unloader piston. The valve plate
assembly consists of laminated and brazed steel plates
which incorporate various valve openings and channels for
UNLOADER
COVER
DISCHARGE
PORT(2)
CRANKCASE
WATER
PORT
CRANKCASE
COVER
CYLINDER
HEAD
VALVE PLATE
ASSEMBLY
OIL PORT
(APPLICATION SPECIFIC)
AIR INLET
PORT
WATER
PORT
GOVERNOR
CONNECTION
conducting air and engine coolant into and out of the cylinder
head.
The discharge valves are part of the valve plate assembly.
The cylinder head, with the valve plate comprise a complete
cylinder head assembly.
The cast iron crankcase and cylinder block assembly, houses
the piston, connecting rod, crankshaft and related bearings.
The BA-921 crankcase cover is stamped with information
identifying the compressor model, customer piece number,
Bendix piece number and serial number. See figure 2.
WATER
PORT
(MAY BE
DRILLED ON
SOME
MODELS)
main local global operation trouble-
menu search search shooting
SD-01-676
BA-921BENDIX AIR POWER COMPRESSOR
UNLOADER
PISTON
CONNECTING
ROD
SPRING
CRANKSHAFT
PISTON
PISTON RINGS
VALVE PLATE ASSY.
CRANKCASE AND
CYLINDER BLOCK
CYLINDER HEAD
BALANCE
PISTON
BACK / RETOUR

BENDIX BA-921 Specifications

General

Brand	BENDIX
Model	BA-921
Category	Air Compressor
Language	English

Summary

Bendix BA-921 Compressor Description

Bendix BA-921 Compressor Operation

Loaded Operation: Air Intake and Compression

Explains the loaded air intake and compression process.

Unloaded Operation: Non-Compression of Air

Details the compressor's unloaded state and function.

Preventative Maintenance and Cooling

Preventative Maintenance Schedule

Outlines regular maintenance intervals and checks.

Compressor Cooling System

Discusses coolant flow and its importance for cooling.

System Inputs and Operational Tests

Air Induction and Lubrication Systems

Covers air intake, induction inspection, and lubrication.

Compressor Drive, Unloader, and Governor

Details compressor drive, unloader, and governor operations.

Operating and Performance Tests

Details compressor performance testing procedures.

Maintenance and Repair Procedures

Leakage Testing Procedures

Outlines methods for testing air system leakage.

Compressor Removal and Disassembly Overview

Provides steps for removing and disassembling the compressor.

Disassembly Steps

Cylinder Head Disassembly

Details the process of taking apart the cylinder head.

Component Servicing and Inspection

Parts Cleaning and Preparation

Instructions for cleaning and preparing compressor parts.

Parts Inspection and Damage Assessment

Guides on inspecting key compressor components for defects.

Assembly, Installation, and Rebuilt Testing

Compressor Assembly Procedures

Steps for reassembling the compressor components.

Compressor Installation and Rebuilt Testing

Guide for installing the compressor and testing rebuilt units.

Technical Specifications and Torque Values

BA-921 Compressor Specifications

Lists key technical data and performance metrics.

Torque Specifications for Assembly

Provides required torque values for assembly fasteners.

Bendix BA-921 Compressor Troubleshooting

Troubleshooting Oil Leaks and Noise Issues

Addresses oil passage, noise, and cooling issues.

Troubleshooting Build-up Time and System Leaks

Covers slow build-up, system leaks, and unloader issues.

Troubleshooting Unloading Failures and Cycling

Diagnoses unloader failure, oil leaks, and rapid cycling.

Troubleshooting Coolant Leaks and Gasket Failures

Focuses on coolant leaks and head gasket integrity.