Pontiac FIREBIRD 1972 Service Manual page 461

SECTION 5C
BENDIX POWER BRAKE
TANDEM DIAPHRAGM
The following caution applies to one or more steps in the assembly proce-
dure of components in this portion of the manual as indicated at appropri-
ate locations by the terminology "See Caution on page 1 of this Section".
CAUTION: THIS FASTENER IS AN IMPORTANT ATTACHING
PART IN THAT IT COULD AFFECT THE PERFORMANCE OF
VITAL COMPONENTS AND SYSTEMS, AND/OR COULD RE-
SULT IN MAJOR REPAIR EXPENSE. IT MUST BE REPLACED
WITH ONE OF THE SAME PART NUMBER OR WITH AN
EQUIVALENT PART IF REPLACEMENT BECOMES NECES-
SAR Y. DO NOT USE A REPLACEMENTPAR T OFLESSER QUAL-
ITY OR SUBSTITUTE DESIGN. TORQUE VALUES MUST BE
USED AS SPECIFIED DURING REASSEMBLY TO ASSURE
PROPER RETENTION OF THIS PART.
CONTENTS OF THIS SECTION
..............................
Trouble Diagnosis and Testing
5C- 1
System Test
..............................................................
5C-1
Vacuum Leak in Released Position
........................
5C-1
Unit Operation
........................................................
5C-1
Vacuum Leak in Holding Position
........................
5C-2
........................................................
Hydraulic Leak 5C-2
Description of Operation
........................................
5C-3
Principles of Operation
............................................
5C-5
Checks and Adjustments
........................................
5C-7
Bleeding System
......................................................
5C-8
.................................................
Stop Lamp Switch 5C-8
..........
Master Cylinder and Power Unit
-
Remove
5C-9
........................................
Master Cylinder Remove 5C-9
Valve Assembly
-
Remove
......................................
5C-9
................................
Power Section
-
Disassemble 5C-10
............................
Master Cylinder
-
Disassemble 5C-12
..................................
Master Cylinder
-
Assemble 5C-13
........................................
Power Unit
-
Assemble 5C-13
..........................................
Push Rod Adjustment 5C-15
..........................
Power Brake Assembly
-
Install 5C-15
TROUBLE DIAGNOSIS AND TESTING
The same types of brake trouble may be encountered with
several times. Each application should provide less and
power brakes as with standard brakes. Before checking
less pedal travel following normal depletion of reserve
power brake system for source of trouble, refer to trouble
vacuum. Number of applications possible on reserve
diagnosis of standard brakes. After these possible causes
vacuum will depend on how hard pedal is pressed and how
have been eliminated, check for cause as outlined below.
far pedal moves. If vacuum assist is not present, an air leak
is indicated.
SYSTEM TEST
2. UNIT OPERATION
1. VACUUM LEAK IN RELEASED POSITION
After depleting reserve vacuum put light pressure on
Run engine with transmission in neutral or park and brake
pedal and start engine. If power system is functioning
released. Stop engine and wait one minute. Apply brake
properly, pedal will fall away slightly.