BENDIX SINGLE ANCHOR PIN CAM BRAKE User Manual

1
®
Bendix
®
Single Anchor Pin Cam Brake
SD-22-3250
FIGURE 1
GENERAL DESCRIPTION
The Bendix
®
15" x 4" single anchor pin cam brake is designed
for use on heavy duty highway vehicles. It is a mechanically
actuated, leading/trailing shoe brake with a fixed position
cam and anchor.
The brake consists of two fabricated steel shoe assemblies
anchored to a cast iron torque spider and actuated by a
single forged S-cam shaft. Two retaining springs secure
the shoe assemblies to the anchor pin. The twin webs of
each shoe assembly are keyed to the anchor pin on one
end and the cam roller on the other. A single shoe to shoe
return spring is used to maintain constant contact between
the shoe, cam roller and cam.
OPERATION
The Bendix
®
cam brake operates in the following manner
during a braking application. The force of the push rod of
the actuator is converted from a linear force to a rotary
torque. This is accomplished by use of the slack adjuster.
This torque is transferred to the cam shaft of the foundation
brake due to the spline of the cam shaft being connected to
the gear of the slack adjuster. On the opposite end of the
cam shaft is the S-cam which when rotated lifts the cam
rollers. This spreads the brake shoe ends apart equally
and pivots the shoes about the anchor pin so the brake
lining comes in contact with the rotating brake drum. The
friction created by the lining pressure against the drum
generates the torque necessary to provide a retarding force
to slow down the vehicle. The energy of the vehicle in motion
is converted to heat at the surface of the drum and lining.
This heat raises the temperature of the drum. The heat is
stored in the drum, and finally dissipated to the air.

BENDIX SINGLE ANCHOR PIN CAM BRAKE Specifications

General

Manufacturer	Bendix
Application	Commercial Vehicles
Actuation	Air actuated
Anchor Type	Single Anchor
Type	Single Anchor Pin Cam Brake

Summary

Bendix Single Anchor Pin Cam Brake Overview

General Description

Overview of the 15" x 4" single anchor pin cam brake design and components.

Operation of the Cam Brake

Explanation of how the Bendix cam brake functions during a braking application.

Preventive Maintenance Guidelines

Brake Adjustment Procedures

Guidelines for weekly brake stroke checks and adjustment procedures.

Brake Lubrication Recommendations

Recommendations for lubricating the camshaft bracket.

Brake Reline Criteria

Criteria for brake lining replacement based on thickness and wear.

Brake Overhaul Guidance

Guidance on when to overhaul the brake system for performance.

Critical Safety Instructions

Critical safety precautions to avoid personal injury or death.

Maintenance Preparation

Disassembly Procedures

Cleaning of Parts

Inspection of Parts

Actuator Bracket and Cam Tube Inspection

Checks for bent bracket or cracked welds and cam tube integrity.

Cam Shaft Inspection

Inspecting the cam shaft for cracks, wear, and roller surface condition.

Spider Inspection

Inspecting the spider for cracks, damage, and anchor pin fit.

Rollers and Pins Inspection

Checking rollers and pins for flat spots, galling, or cracks.

Anchor Pin Inspection

Inspecting the anchor pin for wear, breakage, or cracks.

Shoes and Lining Inspection

Checking brake shoes for damage and lining thickness/wear patterns.

Brake Drum Inspection

Inspecting brake drums for cracks, out-of-roundness, or wear.

Manual Slack Adjuster Inspection

Checking manual slack adjusters for cracks, spline wear, and backlash.

Automatic Slack Adjuster Information

Guidance to consult manufacturer's service information for automatic adjusters.

Actuator Inspection

Inspecting actuators for housing cracks, push rod condition, and yoke wear.

Assembly Procedures

Reline Procedure Details

Foundation Brake Troubleshooting

Degraded Brake Performance

Common causes and remedies for poor brake performance.

Slow Brake Application

Causes and solutions for slow brake application.

Slow Brake Release

Causes and remedies for slow brake release.

Grabbing or Pulling Issues

Troubleshooting causes for brake grabbing or pulling.

Brake Shoe and Lining Troubleshooting

Poor Lining to Drum Contact

Diagnosing and fixing poor lining-to-drum contact issues.

Tapered Lining Wear

Identifying causes for tapered lining wear.

Unequal Wear on Same Brake

Troubleshooting uneven lining wear on a single brake.

Unequal Side-to-Side Wear

Diagnosing uneven wear between brakes on the same axle.

Edge Lining Wear

Identifying causes for lining wear on the edge.

Glazed Linings (Hard and Shiny)

Troubleshooting causes of glazed brake linings.

Scored Linings and Drum

Addressing issues causing scored linings and drums.

Loose Lining Diagnosis

Causes and remedies for loose brake lining installation.

Cracked Lining at Rivet/Bolt Holes

Diagnosing cracked linings at rivet or bolt holes.

Elongated Rivet Holes

Causes and solutions for elongated rivet holes in shoes.

Brake Drum Troubleshooting

Brake Drum Heat Checked

Causes and remedies for heat-checked brake drums.

Excessive Drum Scoring

Troubleshooting excessive scoring on brake drums.