E 450 V8-5.4L (2009)
Brake Master Cylinder: Testing and Inspection
Brake Master Cylinder - Compensator Port
Component Tests
Brake Master Cylinder - Compensator Port
1. With the vehicle in NEUTRAL, position it on a hoist. Refer to Maintenance/Service and Repair.
2. Apply and release the brakes.
3. With the brakes released, attempt to rotate each wheel and check for any brake drag.
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If an excessive amount of brake drag exists at multiple wheels, continue to Step 4.
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If an excessive amount of brake drag exists at only one wheel, it indicates a possible seized brake caliper, brake wheel cylinder or parking
brake component. Repair or install new components as necessary.
4. Check the brake stoplamp switch and the brake pedal free play to verify that the brake pedal is not partially applied.
5. Loosen the brake master cylinder nuts and position the brake master cylinder away from the brake booster.
6. With the brakes released, attempt to rotate each wheel and check for any brake drag.
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If the brake drag is no longer present, install a new brake booster.
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If the brake drag is still present, install a new master cylinder.
