Table of Contents 553 Brake Systems Section 7: Brake Booster Section 7 Topics ................................................................................. 77 Brake Booster ..................................................................................... 78 Booster Operation .............................................................................. 79 Control Valve Closed .......................................................................... 79 Control Valve Open ............................................................................ 79 Booster Air Valve – Brakes Not Applied .............................................
80 Booster Air Valve – Brakes Applied (Vacuum Valve Closed) .............. 81 Booster Air Valve – Brakes Applied (Air Valve Open) ........................ 82 Booster Air Valve – Release Position ................................................. 83 Booster Air Valve – No Vacuum ......................................................... 84 Tandem Brake Booster – Brakes Released ....................................... 85 Tandem Brake Booster – Brakes Applied .......................................... 86 Brake Pressure Conversion Unit ........................................................ 87 Normal Vacuum Operation .................................................................
88 Loss of Vacuum or High Brake Force .................................................. 89 Booster Diagnosis – Operating Check ............................................... 90 Air Tightness Check ........................................................................... 91 Air Tightness Check Under Load ........................................................ 92 Booster Push Rod Gauge .................................................................... 93 Master Cylinder Precautions .............................................................. 94 Mechanical BA Construction ..............................................................
95 Mechanical BA Operation ................................................................... 96 Active Brake Booster .......................................................................... 97 Active Brake Booster – Braking .......................................................... 98 Hydraulic Brake Booster ................................................................... 100 Power Supply Section ...................................................................... 101 Master Cylinder and Brake Booster Construction and Operation ..... 102 Pressure Increase ............................................................................
103 Pressure Reduction ........................................................................... 104 Power Supply Malfunction ................................................................. 105 Front Brake Malfunction .................................................................... 106 Hydraulic Brake Booster Service and Precautions ............................ 107 Master Cylinder Solenoid Bleeding ................................................... 108 Section 8: Hydraulic Brake-force Distribution Section 8 Topics ................................................................................
109 Hydraulic Control ............................................................................... 110 Proportioning Valve Location ............................................................. 111 Hydraulic Pressure Curve .................................................................. 111 Proportioning Valve ........................................................................... 112 Double Proportioning Valve FWD ...................................................... 113 Load Sensing Proportioning Valve (LSPV) ........................................ 114 Proportioning Valve in Unloaded Position .........................................
115 Load Sensing Proportioning and Bypass Valve (LSPBV) ................. 116 Fail-safe Operation ............................................................................ 117 Pressure Gauge SST ......................................................................... 118 LSPV Adjustment .............................................................................. 119 Technical Training iii