Symptom Chart: Brake System

WARNING: This page is about a different car, the 2018 Lincoln Navigator. However, it is still accessible from the selected car via links, so may be relevant.

Diagnostics in this article assume a certain skill level and knowledge of Ford-specific diagnostic practices. REFER to: Diagnostic Methods .

Condition	Possible Sources	Actions
The red brake warning indicator and the yellow ABS warning indicator are illuminated	Diagnostic Trouble Codes (DTCs) in the ABS	CHECK for ABS diagnostic trouble codes (DTCs). REFER to:Anti-Lock Brake System (ABS) and Stability Control .
The red brake warning indicator is always/never on	Brake fluid level switch Parking brake switch Wiring, terminals or connectors IPC BCM	REFER to: Instrumentation, Message Center and Warning Chimes - Vehicles With: Head Up Display (HUD) .
Vehicle pulls or drifts during braking	Brake calipers and/or guide pins Brake flexible hose Brake pads Brake discs	INSPECT the brake system components. INSTALL new components as necessary.
	Tires	REFER to: Wheels and Tires .
	Suspension component(s) and/or wheel alignment	REFER to: Suspension System .
Brake pedal goes down fast or eases down slowly	Brake fluid leaks and/or air in the system	INSPECT the system for visible signs of brake fluid leakage. REPAIR as necessary. BLEED the system. REFER to: Brake System Pressure Bleeding . If no visible signs of leakage are found, INSPECT for brake master cylinder fluid leakage into the brake booster. If there is evidence of fluid in the brake booster, INSTALL a new brake master cylinder and brake booster. REFER to: Brake Master Cylinder . REFER to: Brake Booster . Also, for vehicles equipped with an EcoBoost engine, INSPECT for evidence of brake fluid in the vacuum tube. If there is evidence of brake fluid in the vacuum tube, INSTALL a new vacuum tube.
	Brake master cylinder	CARRY OUT Component Test- Brake Master Cylinder - Bypass Condition .
	HCU	REFER to:Anti-Lock Brake System (ABS) and Stability Control .
	Brake pedal	INSPECT the brake pedal and bracket assembly. INSTALL a new brake pedal and bracket as necessary. REFER to: Brake Pedal and Bracket .
Brakes lock up under light brake pedal force	Brake pads Brake flexible hose Brake disc Brake calipers and/or guide pins	INSPECT the brake system components. INSTALL new components as necessary.
Brakes lock up under light brake pedal force	ABS	REFER to:Anti-Lock Brake System (ABS) and Stability Control .
Excessive brake pedal travel (low/spongy pedal)	Brake fluid leaks and/or air in the system	INSPECT the system for visible signs of brake fluid leakage. REPAIR as necessary. BLEED the system. REFER to: Brake System Pressure Bleeding . If no visible signs of leakage are found, INSPECT for brake master cylinder fluid leakage into the brake booster. If there is evidence of fluid in the brake booster, INSTALL a new brake master cylinder and brake booster. REFER to: Brake Master Cylinder . REFER to: Brake Booster . Also, for vehicles equipped with an EcoBoost engine, INSPECT for evidence of brake fluid in the vacuum tube. If there is evidence of brake fluid in the vacuum tube, INSTALL a new vacuum tube.
	Brake master cylinder	CARRY OUT the Component Test- Brake Master Cylinder - Bypass Condition .
	Brake calipers and/or guide pins	INSPECT the brake calipers and guide pins. INSTALL new components as necessary.
	Brake flexible hose	INSPECT the brake flexible hoses during brake application. INSTALL a new brake hose as necessary. REFER to: Front Brake Flexible Hose . REFER to: Rear Brake Flexible Hose .
Erratic brake pedal travel	Brake pedal	INSPECT the brake pedal for binding, obstructions and correct interface to booster rod. REPAIR as necessary. CHECK the brake pedal fasteners for correct torque. REFER to: Brake Pedal and Bracket .
Erratic brake pedal travel	ABS	REFER to:Anti-Lock Brake System (ABS) and Stability Control .
Brake drag	Parking brake component	INSPECT the parking brake system. INSTALL new components as necessary.
	Brake caliper and/or guide pins Brake flexible hose Brake booster	INSPECT the brake system components. INSTALL new components as necessary.
	Brake master cylinder	CARRY OUT the Component Test- Brake Master Cylinder - Compensator Port .
	Hydraulic Control Unit (HCU)	REFER to:Anti-Lock Brake System (ABS) and Stability Control .
	Stoplamp switch	VERIFY correct installation of the stoplamp switch. REFER to: Stoplamp Switch .
Excessive brake pedal effort	Insufficient vacuum for brake booster operation Brake booster manifold vacuum hose Brake booster Brake booster check valve	CARRY OUT the Component Test- Brake Booster .
Excessive brake pedal effort	Brake pads	INSPECT the brake pads. INSTALL new components as necessary. REFER to: Front Brake Pads . REFER to: Rear Brake Pads .