BENDIX TCH-002-011 Leaflet

Page of 1
   Technical 
Bulletin
Bulletin No: TCH-002-011 
Effective Date: 9/15/2008 
Cancels: N/A 
Page: 1 of  1
Subject:
 
Air Disc Brake Chamber Identifi cation
©  2008 Bendix Commercial Vehicle Systems LLC 9/2008.   All rights reserved.   Printed in U.S.A.
Proper identifi cation is crucial to servicing Bendix
®
 ADB22X
 air disc brake chambers.  Air disc brake chambers 
can be much smaller than typical drum brake chambers in similar vehicle applications.  For example, a common 
drum brake trailer application may utilize a Type 30 service brake chamber where an air disc brake for the same 
trailer application would require a smaller, Type 18 service brake chamber. 
The external diameter of a brake chamber on a drum brake application is often utilized to determine the 
relative size of brake chambers.  However, the external diameter cannot be used for selecting service 
replacement actuators or components for air disc brakes. In some air disc brake applications, even though the 
external diameter of two brake chambers may be identical, the internal components may be different.  It is only 
the internal components creating the application specifi c, balance critical force output that designates these 
brake chambers as, for example, a Type 18 or a Type 20.
To accurately identify the proper brake chamber for replacement in an air disc bake application, the brake 
chamber part number and/or the actual type must fi rst be identifi ed.  This information is permanently attached 
to the chamber. The fi gure(s) below identify common locations for these permanent brake chamber markings.
With this information your authorized Bendix Distributor can properly identify the proper replacement component. 
You can also contact 1-800-AIR-BRAKE (1-800-247-2725) for additional assistance.
Air Disc Brake 
Service Chamber
Air Disc Brake 
Spring Brake 
Chamber
Type / Size
Knorr-Bremse 
Part Number
Bendix Part 
Number
Type / Size
Bendix Part 
Number