Lincoln Aviator: Brake System - General Information / Diagnosis and Testing - Brake System

Symptom Chart(s)

Symptom Chart: Brake System

Diagnostics in this manual assume a certain skill level and knowledge of Ford-specific diagnostic practices.
REFER to: Diagnostic Methods (100-00 General Information, Description and Operation).

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 (206-09 Anti-Lock Brake System (ABS) and Stability Control, Diagnosis and Testing).
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 (413-01 Instrumentation, Message Center and Warning Chimes, Diagnosis and Testing).
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 (204-04A Wheels and Tires, Diagnosis and Testing).
Suspension component(s) and/or wheel alignment  
REFER to: Suspension System (204-00 Suspension System - General Information, Diagnosis and Testing).
Brake pedal goes down fast or eases down slowly Brake fluid leaks and/or air in the system INSPECT the system for leaks. REPAIR as necessary. BLEED the system.
REFER to: Brake System Pressure Bleeding (206-00 Brake System - General Information, General Procedures).
ABS/ HCU  
REFER to: Anti-Lock Brake System (ABS) and Stability Control (206-09 Anti-Lock Brake System (ABS) and Stability Control, Diagnosis and Testing).
Brakes lock up under light brake pedal force
  • Brake pads
  • Brake flexible hose
  • Brake discs
  • Brake calipers and/or guide pins
INSPECT the brake system components. INSTALL new components as necessary.
ABS / HCU  
REFER to: Anti-Lock Brake System (ABS) and Stability Control (206-09 Anti-Lock Brake System (ABS) and Stability Control, Diagnosis and Testing).
Excessive brake pedal travel (low/spongy pedal) Brake fluid leaks and/or air in the system INSPECT the system for leaks. REPAIR as necessary. BLEED the system.
REFER to: Brake System Pressure Bleeding (206-00 Brake System - General Information, General Procedures).
ABS/ HCU  
REFER to: Anti-Lock Brake System (ABS) and Stability Control (206-09 Anti-Lock Brake System (ABS) and Stability Control, Diagnosis and Testing).
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 (206-03 Front Disc Brake, Removal and Installation).
REFER to: Rear Brake Flexible Hose (206-04 Rear Disc Brake, Removal and Installation).
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 (206-06 Hydraulic Brake Actuation, Removal and Installation).
ABS / HCU  
REFER to: Anti-Lock Brake System (ABS) and Stability Control (206-09 Anti-Lock Brake System (ABS) and Stability Control, Diagnosis and Testing).
Brake drag Parking brake component INSPECT the parking brake system.
REFER to: Brake System (206-00 Brake System - General Information, Diagnosis and Testing).
  • Brake caliper and/or guide pins
  • Brake flexible hose
INSPECT the brake system components. INSTALL new components as necessary.
ABS / HCU  
REFER to: Anti-Lock Brake System (ABS) and Stability Control (206-09 Anti-Lock Brake System (ABS) and Stability Control, Diagnosis and Testing).
Stoplamp switch VERIFY correct installation of the stoplamp switch.
REFER to: Stoplamp Switch (417-01 Exterior Lighting, Removal and Installation).
Excessive brake pedal effort ABS/ HCU  
REFER to: Anti-Lock Brake System (ABS) and Stability Control (206-09 Anti-Lock Brake System (ABS) and Stability Control, Diagnosis and Testing).
Brake pads INSPECT the brake pads and, INSTALL new components as necessary.
REFER to: Brake Pads (206-03 Front Disc Brake, Removal and Installation).
REFER to: Brake Pads (206-04 Rear Disc Brake, Removal and Installation).

Symptom Chart: NVH

Diagnostics in this manual assume a certain skill level and knowledge of Ford-specific diagnostic practices.
REFER to: Diagnostic Methods (100-00 General Information, Description and Operation).

Condition Possible Sources Actions
Vibration when the brakes are applied
  • Brake disc(s)
  • Suspension components
  GO to Pinpoint Test A
Brake vibration/shudder occurs when the brake pedal is released Brake drag REFER to Symptom Chart: Brake System
Rattling noise
  • Caliper guide pins or guide pin bolts
  • Missing or damaged anti-rattle clips or springs
  • Loose brake disc shield
  • INSPECT the caliper guide pins and guide pin bolts. INSTALL new components as necessary.
  • INSPECT the brake pads for missing clips or broken springs. INSTALL new components as necessary.
  • TIGHTEN the brake disc shield bolts to specification.
    REFER to: Brake Disc Shield (206-03 Front Disc Brake, Removal and Installation).
    REFER to: Brake Disc Shield (206-04 Rear Disc Brake, Removal and Installation).
Squealing noise - occurs on first (morning) brake application Brake pads Acceptable condition. Caused by humidity and low brake pad temperature.
Squealing noise - a continuous squeal Brake pads INSPECT the brake pads or shoes. INSTALL new components as necessary.
REFER to: Brake Pads (206-03 Front Disc Brake, Removal and Installation).
REFER to: Brake Pads (206-04 Rear Disc Brake, Removal and Installation).
Squealing noise - an intermittent squeal Brake pads Acceptable condition. Caused by cold, heat, water, mud or snow.
Groaning noise - occurs at low speeds with brake lightly applied (creeping) Brake pads Acceptable condition.
Grinding/moaning noise - continuous
  • Brake pads
  • Brake disc
INSPECT the brake pads, brake discs and attaching hardware for damage. VERIFY brake components are within specifications.
REFER to: Brake Pads (206-03 Front Disc Brake, Removal and Installation).
REFER to: Brake Pads (206-04 Rear Disc Brake, Removal and Installation).
REFER to: Brake System (206-00 Brake System - General Information, Diagnosis and Testing).
INSTALL new components as necessary.

Pinpoint Tests

Diagnostics in this manual assume a certain skill level and knowledge of Ford-specific diagnostic practices.
REFER to: Diagnostic Methods (100-00 General Information, Description and Operation).


PINPOINT TEST A : VIBRATION WHEN BRAKES ARE APPLIED

Normal Operation and Fault Conditions

During moderate to heavy braking, noise from the HCU and pulsation in the brake pedal can be observed. Pedal pulsation coupled with noise during heavy braking or on loose gravel, bumps, wet or snowy surfaces is acceptable and indicates correct functioning of the ABS. Pedal pulsation or steering wheel nibble when the brakes are applied (frequency is proportioned to the vehicle speed) indicates a concern with a brake or suspension component.

Possible Sources

  • Brake disc(s)
  • Suspension components
  • Brake pads
A1 ROAD TEST THE VEHICLE - LIGHT BRAKING
  • Road test the vehicle. Warm the brakes by slowing the vehicle from 80 to 32 km/h (50 to 20 mph) using light brake force. At highway speeds of 89-97 km/h (55-60 mph), apply the brake using light pedal force.

Is there a vibration/shudder felt in the steering wheel, seat or brake pedal?
Yes GO to A4
No GO to A2

A2 ROAD TEST THE VEHICLE - MODERATE TO HEAVY BRAKING
  • Road test the vehicle. At highway speeds of 89-97 km/h (55-60 mph), apply the brake using a moderate to heavy pedal force.

Is there a vibration/shudder?
Yes GO to A3
No The concern is not present at this time.

A3 CHECK ABS (ANTI-LOCK BRAKE SYSTEM) OPERATION

NOTE: During moderate to heavy braking, noise from the Hydraulic Control Unit (HCU) and pulsation in the brake pedal can be observed. Pedal pulsation coupled with noise during heavy braking or on loose gravel, bumps, wet or snowy surfaces is acceptable and indicates correct operation of the ABS. Pedal pulsation or steering wheel nibble with the frequency proportional to vehicle speed indicates a concern with a brake or suspension component.

  • Road test the vehicle and apply the brakes on a dry, firm surface, then apply the brakes on a wet, snowy or loose surface (such as gravel).

Is the vibration/shudder only present on a wet, snowy or loose surface?
Yes This is a normal operating condition of the ABS.
No GO to A5

A4 ISOLATE BRAKE VIBRATION

NOTE: This test step is not applicable to vehicles with drum-in-hat type parking brakes. For vehicles with drum-in-hat parking brakes, proceed to the next test step. For all other vehicles, apply the parking brake to identify if the problem is in the front or rear brake.

  • Apply the parking brake to identify if the problem is in the front or rear brake. At highway speeds of 89-97 km/h (55-60 mph), lightly apply the parking brake until the vehicle slows down. Release the parking brake immediately after the test.

Is there a vibration/shudder?
Yes GO to A7
No GO to A5

A5 CHECK THE FRONT SUSPENSION
  • Check the front suspension.

Are all the suspension components in satisfactory condition?
Yes GO to A6
No REPAIR or INSTALL new components as necessary. TEST the system for normal operation.

A6 CHECK THE FRONT BRAKE DISCS
  • Inspect the front brake discs.
    REFER to: Specifications (206-00 Brake System - General Information, Specifications).
    MACHINE or INSTALL new brake discs as necessary. REFER to: Brake Disc Machining (206-00 Brake System - General Information, General Procedures).
    REFER to: Brake Disc (206-03 Front Disc Brake, Removal and Installation).
  • Road test the vehicle.

Is the vibration/shudder present?
Yes GO to A7
No The concern has been repaired.

A7 CHECK THE REAR SUSPENSION
  • Check the rear suspension.

Are all the suspension components in satisfactory condition?
Yes INSPECT the rear brake discs or brake drums.
REFER to: Specifications (206-00 Brake System - General Information, Specifications).
MACHINE or INSTALL new brake discs or drums as necessary.REFER to: Brake Disc (206-04 Rear Disc Brake, Removal and Installation).
REFER to: Brake System (206-00 Brake System - General Information, Diagnosis and Testing).
No REPAIR or INSTALL new components as necessary. TEST the system for normal operation.


    Specifications

      Lubricants, Fluids, Sealers and Adhesives   Specification DOT 4 LV brake fluid WSS-M6C65-A2   Torque Specifications Item Nm lb-ft lb-in Front caliper bleeder screw 8 -- 71 Rear caliper bleeder screw 10 -- 89   Front Disc Brake Specification Item 345 mm 363 mm Front brake disc minimum thickness 1...

    General Procedures - Brake Disc Machining

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