Bendix-commercial-vehicle-systems ASA-5 AUTOMATIC SLACK ADJUSTER 2/11 User Manual download pdf

SD-05-1269

Bendix

ASA-5

Automatic Slack Adjuster

DESCRIPTION

The Bendix

ASA‑5

automatic slack adjuster is designed

for use on cam actuated drum brakes of the type in use

on most highway vehicles. Like a manual slack adjuster,

the ASA‑5

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.

Additionally, the ASA‑5

slack adjuster automatically

adjusts the clearance between the brake lining and drum

to compensate for wear.

A variety of ASA‑5

slack adjuster congurations are offered

including both straight arm and 5/8" yoke offset models.

The ASA‑5

slack adjuster is offered in arm lengths of 5,

5‑1/2 and 6 inches and worm gear splines to accommodate

the standard 1‑1/4" and 1‑1/2" SAE 10C, 24, 28 and 37

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 ASA‑5

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 pushrod stroke.

OPERATION

GENERAL

The automatic adjustment provided by the Bendix

ASA‑5

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 distor tion, or brake component wear.

The ASA‑5

slack adjuster incorporates a clutch‑type

adjuster mechanism that continuously adjusts in very

small increments as lin ing and drum wear occurs. The

adjustments made by the ASA‑5

slack adjuster are,

therefore, not in specic increments relative to actuator

stroke.

BOOT

LINK

LINK PIN

YOKE PIN

YOKE

WORM

GEAR

LUBE

FITTING

FIGURE 1 - ASA-5

AUTOMATIC SLACK ADJUSTER

BRAKE APPLICATION

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

actuator’s push rod causes the ASA‑5

slack adjuster to

rotate the foundation brake camshaft which in turn begins

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

the ASA‑5

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

and shaft. Worm and shaft rotation results in worm gear

rotation which in turn adjusts (or repositions) the brake

camshaft.

When the foundation brake shoes contact the drum, the

camshaft begins to resist rotation and friction between the

worm gear and worm builds, preventing further rotation

1 2 3 4 5 6 ... 11 12

Summary of Contents

Page 1 - Automatic Slack Adjuster

1®SD-05-1269Bendix® ASA-5® Automatic Slack AdjusterDESCRIPTIONThe Bendix® ASA‑5® automatic slack adjuster is designed for use on cam actuated drum bra

Page 2 - BRAKE RELEASE

10ASA-5® SLACK ADJUSTER TROUBLESHOOTING CHART (Continued)SYMPTOMSA. ASA‑5® slack adjuster improperly installed. Too close to actuator: brakes can’t f

Page 3 - INJURY OR DEATH:

Page 4 - INSTALLATION

Page 5 - ACTUATOR STROKE TABLE

2ADAPTERBUSHINGYOKEYOKE PINLINK PINBOOTLUBERELIEFOPENINGCLUTCHSPRINGWORMANTI-REVERSESPRINGSPRINGRETAINERWORMGEARFIGURE 2 - SECTIONAL VIEW OF PROFILE A

Page 6 - ADJUSTER MECHANISM

32. Stop the engine and remove ignition key when working under or around the vehicle. When working in the engine compartment, the engine shou

Page 7 - DISASSEMBLY

4FIGURE 6 - INSTALLATION ANGLEINITIAL INSTALLATION PREPARATION1. If necessary, carefully remove the manual or automatic slack adjuster currently inst

Page 8 - ADJUSTER

5Visually check for physical damage such as broken air lines and broken or missing parts.Every 25,000 miles, or 3 months, or 500 operating hours or a

Page 9

6that a problem exists with the automatic adjuster, with the installation of the adjuster, or with related foundation brake components, which

Page 10

7C. Rotate the manual adjustment hex counterclockwise until the ASA‑5® slack adjuster is clear of the brake actuator push rod.Note: Considerably more

Page 11

8CLEANING AND INSPECTION1. Inspect the worm gear camshaft splines for damage. If damaged, replace the ASA‑5® slack adjuster.2. Clean and inspect the

Page 12

9A. Reposition components and torque to specication.B. Replace damaged or worn parts.ASA-5® SLACK ADJUSTER TROUBLESHOOTING CHARTSYMPTOMS1. Brake A

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Bendix-commercial-vehicle-systems ASA-5 AUTOMATIC SLACK ADJUSTER 2/11 User Manual

Browse online or download User Manual for Equipment Bendix-commercial-vehicle-systems ASA-5 AUTOMATIC SLACK ADJUSTER 2/11. Bendix Commercial Vehicle Systems ASA-5 AUTOMATIC SLACK ADJUSTER 2/11 User Manual

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