BENDIX TCH-001-060 User Manual

Technical Bulletin

Bulletin No: Effective Date: Cancels: Page: 1 of
Subject:

This bulletin is in reference to Bendix® BA-921® and BA-922® compressors installed on Detroit Diesel DD15™
and DD13™ engines. These compressors contain an Energy Saving System (ESS) within the cylinder head
that may require servicing while the compressor is still covered under warranty. The life expectancy of the
ESS varies according to the vehicle vocation and duty cycle. High air usage systems will result in reduced
life of the compressor ESS. In such cases, the ESS can be diagnosed for leakage and replaced if necessary .

This bulletin details the proper diagnostic and replacement procedures for the ESS. Failure to follow these

procedures may result in a denied warranty claim if the ESS portion of the compressor, submitted
for warranty consideration, is deemed causal. Note that if excessive carbon is present in the discharge

fi tting of the compressor, with a fi lm greater than 10% of the inside diameter, the entire compressor should
be replaced.

If the nature of the compressor issue, or complaint, is any of the following; the ESS is the likely source
(assuming that checks for other system malfunctions have been carried out).

(A) ESS leaking when pressurized (D) Compressor not unload
(B) Compressor safety valve popping off (E) System will not build air pressure
(C) Air dryer purge valve and compressor (F) System slow to build
cycling rapidly (G) Compressor leaking air

TCH-001-060

1-13-2011

ESS REPLACEMENT FOR BENDIX® BA-921® & BA-922® COMPRESSORS - REVISED

Closed Room Compressor Typical System

TCH-001-060 dated 12-2-2010

4

Governor Unloader

Por t

Governor

Reservoir Port

Compressor

DIAGNOSING THE UNLOADER SYSTEM FOR PROPER OPERATION AND PRESSURE SETTING

When performing any service, be sure to follow all safety guidelines outlined in the BA-921
compressor service data sheets, SD-01-690 or SD-01-700, or instruction sheet as applicable.

1. Using shop air, pressurize the unloader line to 120 psi and check for leaks in this line. Remove the air
pressure and ensure the unloader line is properly seated in the governor fi tting. Using shop air, check the
unloader line, again, for leaks. If there are no leaks, return the vehicle to service. If a leak is still present,
go to step 2.

2. Remove the compressor from the vehicle and closely inspect for any non-ESS related issues. If there are
non-ESS issues, submit the compressor for warranty consideration.

3. If there aren’t any obvious non-ESS related issues, service the ESS using the ESS service replacement
kit as outlined in this bulletin.

Air Dryer

Purge Valve

Cycling

Supply

Reservoir

®

or BA-922®

Continued...

Bulletin No: Page: 2 of

TCH-001-060

ESS SERVICE REPLACEMENT KIT CONTENTS

4

Balance Piston

Balance Piston O-ring

Spring

ESS Piston Assembly

Gasket

Lubricant

ESS Kit Part Nos

Bendix Detroit Diesel

K046477 A000 130 5819

THE FOLLOWING GUIDELINES ARE FOR REFERENCE. THE ESS SERVICE REPLACEMENT KIT
CONT AINS ADDITIONAL INSTRUCTIONS.

ESS REMOVAL AND CLEANING

Refer to the illustrations below. If the compressor being serviced is under warranty, retain the removed
components for warranty consideration.

Note: The Bendix

®

BA-922® compressor uses two ESS assemblies. Perform steps 1 through 3 for each

ESS assembly.

1. Using a T25 Torx head screwdriver, remove the ESS cover plate screws and ESS cover plate from the
compressor cylinder head.

2. Remove the balance piston, balance piston o-ring, spring, and ESS piston assembly from the cylinder
head.

Cover Plate

Gasket

Balance Piston

Balance Piston O-ring

Spring

ESS Piston Assembly

3. Thoroughly clean the cylinder head and ESS cover plate; removing all dirt, carbon, grease, gasket materials
and any foreign matter from the ESS piston cavity.

.

Cylinder Head