F 350 2WD Pickup V8-7.3L DSL (1988)
Brake Master Cylinder: Component Tests and General Diagnostics
F1- Fluid Level Check
^ Check fluid level in master cylinder reservoir.
^ Full reservoir?
YES -- Go to F2. See: F - Master Cylinder Visual Inspection/F2 - Fluid Level Condition
^ Low or empty reservoir with no brake warning lamp on?
YES -- Replace master cylinder brake reservoir.
F2 - Fluid Level Condition
^ Apply and release brake pedal one full stroke.
^ Observe reservoir fluid level of both chambers as pedal is released.
^ Does fluid level remain constant?
YES -- Go to F3. See: F - Master Cylinder Visual Inspection/F3 - Master Cylinder Condition
NO -- External leak in master cylinder. Repair as required.
F3 - Master Cylinder Condition
^ Wipe off exterior of master cylinder, cover and gasket with clean cloth.
^ Road test vehicle and pump brakes.
^ Check if master cylinder exterior is dry or wet.
^ Check for fluid from bore end of booster or dash.
^ Is master cylinder exterior dry?
YES -- Go to F4. See: F - Master Cylinder Visual Inspection/F4 - Master Cylinder Condition
NO -- External leak in master cylinder. Repair master cylinder.
F4 - Master Cylinder Condition
^ Hold pressure on pedal until pedal goes down.
^ Pedal goes down 3.175mm (1/8-in) or more, each time the pedal is released?
YES -- Check entire brake system for major leak. Repair as required.
NO -- Refer to diagnosis by symptom. See: Testing and Inspection/Symptom Related Diagnostic Procedures
G1 - Verify Condition
^ Road test vehicle only if condition cannot be verified in shop.
^ Statically depress brake pedal.
^ Does brake pedal operate properly?
YES -- Vehicle OK.
NO -- Go to G2. See: G - Pedal Goes Down Fast/G2 - Brake Fluid Level
G2 - Brake Fluid Level
^ Check master cylinder brake fluid reservoir level.
