BENDIX BW7499 User Manual download pdf

SD-05-4630

Bendix

Versajust

™

Automatic Slack Adjuster

DESCRIPTION

The Bendix

Versajust

™

automatic slack adjuster is

designed for use on cam-actuated drum brakes, the

type in use on most highway vehicles. Like a manual

slack adjuster, the Versajust

™

slack adjuster multiplies

and transforms the linear force of the air actuator into

a rotational force, or torque, which is used to apply the

foundation brake. In addition, the Versajust slack adjuster

automatically adjusts the clearance between the brake

lining and drum to compensate for wear.

A variety of Bendix Versajust slack adjuster congurations

are offered, including both straight arm and

/8" yoke offset

models. The Versajust slack adjuster is offered in arm

lengths of 5, 5

/2 and 6 inches, and worm gear splines to

accommodate the standard 1

/4" and 1

/2" SAE 10C-, 24-,

and 28-tooth splines.

Either of two yoke designs (easy-on and quick connect) in

combination with an external manual adjuster hex provides

for convenient installation and maintenance of the Bendix

Versajust slack adjuster. Note: The manual adjuster

hex is intended for use during installation. CAUTION:

Automatic slack adjusters should not be adjusted

manually to correct excessive push rod stroke.

OPERATION

GENERAL

The automatic adjustment provided by the Bendix Versajust

slack adjuster results in consistent brake-lining-to-drum-

clearance and brake actuator stroke. The key to its

operation is the ability to complete the brake adjustment

during the early part of each brake application and to cease

adjusting as resistance to brake cam rotation begins to

build. This aspect of the adjuster mechanism’s operation

prevents over-adjustment caused by lining compression,

actuator bracket deection, drum and foundation brake

component distortion, or brake component wear.

The Versajust slack adjuster incorporates a clutch-type

adjuster mechanism that continuously adjusts – in very

small increments – as lining and drum wear occurs. The

adjustments made by the Versajust slack adjuster are,

therefore, not in specic increments relative to actuator

stroke.

FIGURE 1 - BENDIX

VERSAJUST

™

AUTOMATIC SLACK

ADJUSTER

Note that the Versajust automatic slack adjuster is

compatible with Bendix

ASA-5

automatic slack adjusters.

Therefore, it is acceptable to have a Versajust automatic

slack adjuster on one side of the axle and an ASA-5

automatic slack adjuster on the other side of the same axle.

BRAKE APPLICATION

When the brakes are applied, the linear travel of the brake

actuator’s push rod causes the Versajust slack adjuster to

rotate the foundation brake camshaft, which in turn begins

to force the brake shoes into contact with the drum. When

the Versajust slack adjuster rotates, the yoke assembly

pivots on the yoke pin, causing the link to be pulled upward.

The “teeth” on the link mesh with the adjuster mechanism

pinion. As the link is pulled, it travels rst through its free

play and then causes the pinion to rotate. Rotation of the

pinion is transmitted through the clutch spring to the worm

MANUAL

ADJUSTMENT

HEX

BOOT

LINK

YOKE

WORM

GEAR

Compatible with

Bendix

ASA-5

Automatic Slack

Adjusters

LUBE FITTING

1 2 3 4 5 6 7 8

Summary of Contents

Page 1 - Automatic Slack Adjuster

1®SD-05-4630Bendix® Versajust™ Automatic Slack AdjusterDESCRIPTIONThe Bendix® Versajust™ automatic slack adjuster is designed for use on cam-actuated

Page 2 - PERSONAL INJURY OR DEATH:

2of the Versajust slack adjuster toward the released position causes the link to rotate the pinion. The anti-reverse spring prevents counterclockwise

Page 3 - QUICK-CONNECT YOKE

3A. With the brake chamber in the released position, place a square (or an equivalent object) so that one edge is parallel to the actuator push rod,

Page 4 - INSTALLATION

4environmental conditions, an application of anti-seize compound to both the camshaft and worm gear spline may facilitate later slack removal.INSTALLA

Page 5

53. Measure the brake actuator push rod stroke while making an 80-90 psi service brake application. Actuator push rod strokes should not exceed the

Page 6

6BRAKE MAINTENANCE INSPECTIONNote: Make certain the vehicle has been prepared according to the instructions under the heading GENERAL SAFETY GUIDELINE

Page 7 - RETROFITTING THE BENDIX

7CLEANING AND INSPECTION1. Inspect the worm gear camshaft splines for damage. If damaged, replace the Versajust slack adjuster.2. Clean and inspect

Page 8 - Versajust

8The Bendix® Versajust™ Slack Adjuster Troubleshooting ChartSymptom Cause Remedy1. Brake Actuator stroke is too long. WARNING: Automatic slack adjus