5C – 28 POWER ASSISTED BRAKE SYSTEM
P & B (PROPORTIONING AND BYPASS) VALVE
Master cylinder
(Primary)
Master cylinder
(Secondary)
Rear brake
Front brake
INSTALLATION
To install, follow the removal steps in the reverse
order, noting the following points. After installing the
brake pipes, bleed brakes as described in this section.
1. Tighten the brake pipes to the specified torque.
Brake Pipe Torque
N·m(kg·m/lb·ft)
Master Cylinder Side
Others
12 (1.2/9)
16 (1.6/12)
The P & B valve contains two sections, each serving a
different function.
The proportioning section of the P & B valve
proportions outlet pressure to the rear brakes after a
predetermined rear input pressure has been reached.
This is done to prevent rear wheel lock-up on the
vehicles with light rear wheel loads.
The valve has a By-bass feature which assures full
system pressure to the rear brakes in the event of a
font brake mulfunction, also full front pressure is
retained in the event of rear brake mulfunction.
The P & B valve is not repairable and must be
replaced as a complete assembly.