Page M- i
Repair and Service Manual
MECHANICAL BRAKES
TABLE OF CONTENTS FOR SECTION ’M’
SECTION TITLE
PAGE NO.
BRAKE SYSTEM OVERVIEW ...................................................................................................................................M - 1
General Description .......................................................................................................................................M - 1
How the Service Brake Works .......................................................................................................................M - 2
Equalizer Link ................................................................................................................................................M - 2
Automatic Adjuster Mechanism .....................................................................................................................M - 2
How the Parking Brake Works .......................................................................................................................M - 2
Compensator Assembly .................................................................................................................................M - 3
Kick-Off Actuating Linkage ............................................................................................................................M - 3
TROUBLESHOOTING FLOWCHART ........................................................................................................................M - 4
TROUBLESHOOTING TABLE ...................................................................................................................................M - 6
TROUBLESHOOTING AND INSPECTION ................................................................................................................M - 8
New Vehicles .................................................................................................................................................M - 8
Troubleshooting and Inspection Procedures .................................................................................................M - 8
Brake Pedal and Linkage Inspection .............................................................................................................M - 8
Periodic Brake Performance Test (PBPT) ...................................................................................................M - 10
Aggressive Stop Test ...................................................................................................................................M - 11
Wheel Brake Inspection ...............................................................................................................................M - 12
MAINTENANCE AND REPAIRS ..............................................................................................................................M - 14
Parts Replacement vs. Repair .....................................................................................................................M - 14
Adjusting Brake Pedal Free Travel ..............................................................................................................M - 14
Brake Drum Removal and Installation .........................................................................................................M - 16
Wheel Brake Service ...................................................................................................................................M - 16
Backing Plate/Entire Wheel Brake Assembly Removal and Installation ......................................................M - 17
Brake Shoe and Adjuster Replacement .......................................................................................................M - 18
Brake Cable and Equalizer Assembly Removal and Installation .................................................................M - 19
Compensator Assembly, Removal and Installation .....................................................................................M - 19
Brake Pedal Removal and Installation .........................................................................................................M - 19
Parking Brake Catch Bracket Removal and Installation ..............................................................................M - 20
Parking Brake Pedal, Removal and Installation ...........................................................................................M - 20
Pedal Bumper Adjustment ...........................................................................................................................M - 20
Parking Brake Release Linkage Removal and Replacement ......................................................................M - 21
Parking Brake Kick-Off Cam Removal, Replacement and Installation ........................................................M - 21
LIST OF ILLUSTRATIONS
Fig. 1 Mechanical Brake System ...............................................................................................................................M - 1
Fig. 2 Wheel Brake Adjustment .................................................................................................................................M - 2
Fig. 3 Parking Brake and Kick-Off Mechanism ..........................................................................................................M - 3
Fig. 4 Compensator Assembly ..................................................................................................................................M - 3
Fig. 5 Troubleshooting Flowchart .............................................................................................................................M - 4
Fig. 6 Troubleshooting Table .....................................................................................................................................M - 6
Fig. 7 Brake Pedal Bumper Inspection ......................................................................................................................M - 8
Fig. 8 Brake Pedal Inspection ....................................................................................................................................M - 8
Fig. 9 Checking for Excessive Free Travel ................................................................................................................M - 9
Fig. 10 Equalizer and Compensator ..........................................................................................................................M - 9
Fig. 11 Parking Brake Pedal Hinge Inspection ........................................................................................................M - 10
Fig. 12 Kick-Off Cam Inspection ..............................................................................................................................M - 10
Fig. 13 Periodic Brake Performance Test ................................................................................................................M - 11
Fig. 14 Equally Load Vehicle ...................................................................................................................................M - 12
Fig. 15 Adjuster Mechanism ....................................................................................................................................M - 13
Fig. 16 Brake Shoe Wear ........................................................................................................................................M - 13
Fig. 17 Orientation of Brake Shoe Springs ..............................................................................................................M - 14
Fig. 18 Free Travel Adjustment ...............................................................................................................................M - 15
Fig. 19 Check Clevis Pins ........................................................................................................................................M - 15