There is no isolated proportion valve.

Front / rear split system, the master cylinder is the proportion control.

Majority stopping power is roughly 75% FRONT brakes.

Alert: Brake pedal height is 75% REAR, and stopping power roughly 25% rear brakes.

For Safety: Always bleed front brakes first = 75%, then rear 25% + pedal height.

FYI: Critical functions = STEERING + BRAKES, everything else is inconvenient irritating or frustrating.

Have a great day.

.

__________________
ASE Master Mechanic

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D

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