Lincoln Nautilus Manuals

Lincoln Nautilus: Brake System - General Information / Brake System. Diagnosis and Testing

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).
Brake master cylinder CARRY OUT the Brake Master Cylinder - Bypass Condition Component Test.
  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).
Brake pedal INSPECT the brake pedal simulator spring, cam and interface-to-booster. INSTALL a new brake pedal and bracket as necessary.
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.
  ABS  
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).
Brake master cylinder CARRY OUT the Brake Master Cylinder - Bypass Condition Component Test.
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  
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. 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 Brake Master Cylinder - Compensator Port Component Test.
  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).
Stoplamp switch VERIFY correct installation of the stoplamp switch.
REFER to: Stoplamp Switch (417-01 Exterior Lighting, Removal and Installation).
Excessive brake pedal effort Vacuum on demand system fault Using a diagnostic scan tool, CARRY OUT the PCM self-test. DIAGNOSE all PCM Diagnostic Trouble Codes (DTCs).
  • Insufficient vacuum for brake booster operation
  • Brake booster manifold vacuum hose
  • Brake booster
  • Brake booster check valve
  • Brake booster vacuum pump
CARRY OUT the Brake Booster Component Test in this section.
Brake pads INSPECT the brake pads.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. 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. 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)/drums(s)
  • Suspension components
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 or electronic parking brakes. For vehicles with drum-in-hat or electronic 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. 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. 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).
No REPAIR or INSTALL new components as necessary. TEST the system for normal operation.


Component Test- Brake Booster

  1. Disconnect the brake booster vacuum sensor/check valve from the brake booster and connect a suitable vacuum/pressure tester to the booster side of the vacuum sensor/check valve.
  1. Apply the parking brake, start the engine and place the transmission in NEUTRAL.
    • Allow the engine to reach normal operating temperature.
  1. Verify that vacuum is available at the vacuum sensor/check valve with engine running at normal idle speed.
    • The vacuum gauge should read between 51-74 kPa (15-22 in-Hg).
    • If specified vacuum is available, stop the engine, connect the vacuum sensor/check valve and continue with Step 5.
    • If specified vacuum is not available, continue with Step 4.
  1. Disconnect the vacuum sensor/check valve from the vacuum hose and verify that the specified vacuum is available at the hose with the engine at idle speed and the transmission in NEUTRAL.
    • If specified vacuum is available, stop the engine, install a new check valve and continue with Step 5.
    • For vehicles equipped with a brake vacuum pump, if specified vacuum is not available, inspect the vacuum hose and install new as necessary. If the vacuum hose is ok, install a new vacuum pump.
      REFER to: Brake Vacuum Pump - 2.7L EcoBoost (238kW/324PS) (206-07 Power Brake Actuation, Removal and Installation).
    • For vehicles not equipped with a brake vacuum pump, if specified vacuum is not available, stop the engine, connect the vacuum hose to the check valve and diagnose the no/low vacuum condition.
  1. Apply the brake pedal several times to exhaust all vacuum from the system.
  1. Apply the brake pedal and hold it in the applied position. Start the engine and verify that the brake pedal moves downward after the engine starts.
    • If the brake pedal moves, the brake booster is operating correctly.
    • If the brake pedal does not move, install a new brake booster.
      REFER to: Brake Booster (206-07 Power Brake Actuation, Removal and Installation).
  1. Operate the engine a minimum of 20 seconds at idle. Stop the engine and let the vehicle stand for 10 minutes, then apply the brake pedal. The brake pedal feel should be the same as that noted with the engine operating.
    • If the brake pedal feels hard (no power assist), install a new brake booster vacuum sensor/check valve and retest.
    • If condition still exists, install a new brake booster.
      REFER to: Brake Booster (206-07 Power Brake Actuation, Removal and Installation).
    • If the brake pedal feels the same as noted with the engine operating, the vacuum sensor/check valve is functioning properly.

Component Test- Brake Master Cylinder - Bypass Condition

  1. Inspect the master cylinder.
  1. Disconnect the brake tubes from the master cylinder.
  1. NOTE: Make sure the outlet port plugs do not show signs of leakage.

    Plug the outlet ports of the master cylinder.
  1. Lightly apply the brakes and hold for 10 seconds. Release the brakes and then reapply with heavy force. If brake pedal height cannot be maintained, the brake master cylinder has an internal leak and a new brake master cylinder must be installed.
  • If brake pedal height is maintained, reinstall brake tubes and tighten to specification.
    REFER to: Brake Master Cylinder (206-06 Hydraulic Brake Actuation, Removal and Installation).
    After installation, bleed the brake system. REFER to: Brake System Pressure Bleeding (206-00 Brake System - General Information, General Procedures).

Component Test- Brake Master Cylinder - Compensator Port

  1. Inspect the master cylinder.

  1. REFER to: Jacking and Lifting - Overview (100-02 Jacking and Lifting, Description and Operation).
  1. Apply and release the brakes.
  1. With the brakes released, attempt to rotate each wheel and check for any brake drag.
  • If an excessive amount of brake drag exists at multiple wheels, continue to Step 5.
  • 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.
  1. Check the brake stoplamp switch and the brake pedal free play to verify the brake pedal is not partially applied.
  1. Loosen the brake master cylinder nuts and position the brake master cylinder away from the brake booster.
  1. With the brakes released, attempt to rotate each wheel and check for any brake drag.
  • If the brake drag is no longer present, install a new brake booster.
    REFER to: Brake Booster (206-07 Power Brake Actuation, Removal and Installation).
  • If the brake drag is still present, install a new master cylinder.
    REFER to: Brake Master Cylinder (206-06 Hydraulic Brake Actuation, Removal and Installation).

    Specifications

    ..

    Brake Disc Machining. General Procedures

    Repair NOTE: Do not machine the brake discs for any brake noise concern (squeal, squeak, moan, groan, grunt, grind, etc.). Brake disc machining is allowed if one of the below conditions is present; Excessive corrosion/rust and/or pitting on the braking surface...

    Other information:

    Lincoln Nautilus 2018-2022 Service Manual: Wheels and Tires. Diagnosis and Testing


    Preliminary Inspection Verify the customer concern by carrying out a road test on a smooth road. If any vibrations are apparent, Refer to the Symptom Chart: NVH. To maximize tire performance, inspect for signs of incorrect inflation and uneven wear, which may indicate a need for balancing, rotation or front suspension alignment...

    Lincoln Nautilus 2018-2022 Owners Manual: Audio System


    Audio System Precautions WARNING: Driving while distracted can result in loss of vehicle control, crash and injury. We strongly recommend that you use extreme caution when using any device that may take your focus off the road. Your primary responsibility is the safe operation of your vehicle...

    Categories

    Locating the Pre-Collision Assist Sensors

    Lincoln Nautilus. Locating the Pre-Collision Assist Sensors

    Camera. Radar sensor (if equipped).

    If a message regarding a blocked sensor or camera appears in the information display, something is obstructing the radar signals or camera images. The radar sensor is behind the fascia cover in the center of the lower grille. With a blocked sensor or camera, the system may not function, or performance may reduce. See Pre-Collision Assist – Information Messages.

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