Technical Bulletin
Bulletin No: | Effective Date:9/12/2011 | Cancels: | Page: 1 of 1 |
Subject: Brake Actuator Push Rod Qualifications for Use with Bendix®
This Bulletin updates Bendix Commercial Vehicle Systems LLC guidelines for push rods used with Bendix® ASA‑5® and Bendix® Versajust™ automatic slack adjusters.
Both these slack adjusters adjust the clearance between the brake linings and the drums during a brake application and require push rods with the following specifications to be used:
1.For push rods up to eight (8) inches in length, must be made with steel with strength that meets or exceeds SAE 1018 or equivalent grade (based on the yield strength of the material). (See dimension A shown below).
A
A
Push rod length ‘A’ is measured from the bottom of the actuator to the end of the push rod. This dimension is taken with the spring brakes released or caged.
2.Without exception, in cases where longer push rods are necessary, they must be made from steel with strength that meets or exceeds SAE 1035 or equivalent grade (based on the yield strength of the material). In these cases, the push rod must be a minimum of 0.625 inch in diameter and only partially threaded (i.e. Only threaded the first three to four inches at the end of the rod).
3 - 4 inches 
max.
Push
Rod
Diameter
WARNING. Brake actuator push rods that do not meet these recommendations can be permanently deformed by the forces generated during a braking application. Bent brake actuator push rods may negatively affect the braking performance at the wheel end.
If you have further questions, contact your Bendix Account Manager or call
Reference Materials
See the following Bendix Service Data sheets available from the document library at www.bendix.com or from the Literature Center at the web site:
© 2011 Bendix Commercial Vehicle Systems LLC, a member of the
