Lincoln Navigator: Suspension System - General Information / Suspension System. Diagnosis and Testing

Preliminary Inspection

1. Road test the vehicle.
   
   • If any suspension alignment or ride height concerns are present, REFER to Symptom Chart: Suspension System.
     
   • Verify the customer concern by carrying out a road test on a smooth road. If any vibrations are present, REFER to Symptom Chart: NVH .
     

1. Inspect the tires.
   
   • Check the tire pressures with all normal loads in the vehicle and the tires cold. REFER to the VC label.
     
   • Verify that all tires are sized to specification. REFER to the VC label.
     
   • Inspect the tires for incorrect wear and damage. INSTALL new tires as necessary.
     

1. Inspect the chassis and underbody.
   
   • Remove any excessive accumulation of mud, dirt or road deposits from the chassis and underbody.
     
   • Front or rear suspension components.
     
   • Suspension fastener(s).
     
   • Incorrect spring usage Spring(s).
     
   • Shock absorber(s).
     
   • Strut(s).
     
   • Suspension bushing(s).
     
   • Steering system components.
     
   • Wheel bearing and wheel hub(s).
     

1. Inspect for aftermarket equipment.
   
   • Check for aftermarket changes to the steering, suspension, and wheel and tire components (such as competition or heavy duty). The specifications shown in this manual do not apply to vehicles equipped with aftermarket equipment.
     

Symptom Chart: Suspension 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
Vehicle drifts/pulls	Refer to the Diagnostic Routine.	REFER to the symptom chart.    Click here to access Guided Routine (EPAS).
Wander	Overloaded, unevenly or incorrectly loaded vehicle	NOTIFY the customer of incorrect vehicle loading.
	Ball joint(s)	CARRY OUT a ball joint inspection. INSTALL new control arm(s) as necessary. REFER to: Lower Ball Joint (204-01A Front Suspension - LHD RWD, Removal and Installation). REFER to: Lower Ball Joint (204-01B Front Suspension - LHD 4WD, Removal and Installation).
	Damaged or missing front strut mount bearing(s)	INSTALL a new front strut mount bearing(s) as necessary. REFER to: Shock Absorber and Spring Assembly (204-01A Front Suspension - LHD RWD, Removal and Installation). REFER to: Shock Absorber and Spring Assembly (204-01B Front Suspension - LHD 4WD, Removal and Installation).
	Loose, worn or damaged front wheel bearing(s)	INSPECT the wheel bearings. INSTALL new wheel bearings as necessary. REFER to: Front Wheel Bearing and Wheel Hub (204-01A Front Suspension - LHD RWD, Removal and Installation). REFER to: Front Wheel Bearing and Wheel Hub (204-01B Front Suspension - LHD 4WD, Removal and Installation).
	Loose, worn or damaged suspension component(s)	INSTALL new suspension component(s) as necessary.
	Loose suspension fasteners	NOTE: Do not lubricate fasteners. INSPECT the suspension fasteners. TIGHTEN to specifications.
	Steering components	INSPECT the steering system. INSTALL new components as necessary.
	Wheel alignment (excessive total front toe out)	ADJUST as necessary. REFER to: Front Toe Adjustment (204-00 Suspension System - General Information, General Procedures).
Front bottoming or riding low	Worn, damaged or incorrect springs	MEASURE the ride height. REFER to: Ride Height Measurement (204-00 Suspension System - General Information, General Procedures). INSTALL new springs as necessary. REFER to: Shock Absorber and Spring Assembly (204-01A Front Suspension - LHD RWD, Removal and Installation). REFER to: Shock Absorber and Spring Assembly (204-01B Front Suspension - LHD 4WD, Removal and Installation).
	Worn front strut(s)	INSTALL new struts as necessary. REFER to: Shock Absorber and Spring Assembly (204-01A Front Suspension - LHD RWD, Removal and Installation). REFER to: Shock Absorber and Spring Assembly (204-01B Front Suspension - LHD 4WD, Removal and Installation).
Abnormal/incorrect tire wear	Incorrect tire pressure (rapid center rib or inner and outer edge wear)	ADJUST the tire pressure. REFER to VC label.
	Incorrect tire rotation intervals	REFER to Owners Literature for correct tire rotation intervals.
	High-speed cornering Excessive front or rear toe (inner or outer edge wear) Excessive negative or positive camber (inner or outer edge wear)	REFER to: Wheels and Tires (204-04A Wheels and Tires, Diagnosis and Testing).
	Front or rear suspension components	INSPECT the front and rear suspension system. REPAIR or INSTALL new suspension components as necessary.
Sticky steering, poor returnability	Damaged or worn front strut mount bearing(s)	INSTALL a new front strut mount bearing(s) as necessary. REFER to: Shock Absorber and Spring Assembly (204-01A Front Suspension - LHD RWD, Removal and Installation). REFER to: Shock Absorber and Spring Assembly (204-01B Front Suspension - LHD 4WD, Removal and Installation).
	Binding ball joints	CARRY OUT a ball joint inspection. INSTALL new ball joint(s) as necessary. REFER to: Lower Ball Joint (204-01A Front Suspension - LHD RWD, Removal and Installation). REFER to: Lower Ball Joint (204-01B Front Suspension - LHD 4WD, Removal and Installation).
	Steering components	INSPECT the steering system. INSTALL new components as necessary. REFER to: Power Steering (211-02 Power Steering, Diagnosis and Testing).
Steering wheel off-center	Unequal front toe setting (side-to-side)	CHECK the wheel alignment. REFER to: Front Toe Adjustment (204-00 Suspension System - General Information, General Procedures).
	Steering components	INSPECT the steering system. INSTALL new components as necessary
Sway or roll	Overloaded, unevenly or incorrectly loaded vehicle	NOTIFY the customer of incorrect vehicle loading.
	Loose wheel nut(s)	TIGHTEN the wheel nut(s) to specification. REFER to: Wheel and Tire (204-04A Wheels and Tires, Removal and Installation).
	Strut(s) or shock absorber(s)	INSTALL new struts or shock absorbers as necessary. REFER to: Shock Absorber and Spring Assembly (204-01A Front Suspension - LHD RWD, Removal and Installation). REFER to: Shock Absorber and Spring Assembly (204-01B Front Suspension - LHD 4WD, Removal and Installation). REFER to: Shock Absorber and Spring Assembly (204-02 Rear Suspension, Removal and Installation).
	Loose stabilizer bracket-to-frame bolts	TIGHTEN the bolts to specification. REFER to: Front Stabilizer Bar (204-01A Front Suspension - LHD RWD, Removal and Installation). REFER to: Front Stabilizer Bar (204-01A Front Suspension - LHD RWD, Removal and Installation).
	Worn stabilizer bar bushings or links	INSTALL new stabilizer bar bushings or links as necessary. REFER to: Front Stabilizer Bar (204-01A Front Suspension - LHD RWD, Removal and Installation). REFER to: Front Stabilizer Bar (204-01A Front Suspension - LHD RWD, Removal and Installation). REFER to: Front Stabilizer Bar Link (204-01A Front Suspension - LHD RWD, Removal and Installation). REFER to: Front Stabilizer Bar Link (204-01B Front Suspension - LHD 4WD, Removal and Installation).
	Damaged or broken stabilizer bar	INSTALL a new stabilizer bar as necessary.
	Worn spring(s)	INSTALL new springs as necessary.INSTALL new struts or shock absorbers as necessary. REFER to: Shock Absorber and Spring Assembly (204-01A Front Suspension - LHD RWD, Removal and Installation). REFER to: Shock Absorber and Spring Assembly (204-01B Front Suspension - LHD 4WD, Removal and Installation). REFER to: Shock Absorber and Spring Assembly (204-02 Rear Suspension, Removal and Installation).
Vehicle leans to one side	Unevenly loaded or overloaded vehicle	NOTIFY the customer of incorrect vehicle loading.
	Front or rear suspension components	INSPECT the front and rear suspension systems. INSTALL new suspension components as necessary.
	Incorrect drive axle(s) ride height. Side-to-side lean out of specification	MEASURE the ride height. REFER to: Ride Height Measurement (204-00 Suspension System - General Information, General Procedures). INSPECT the front and rear suspension systems. REPAIR or INSTALL new components as necessary

• If an obvious cause for an observed or reported condition is found, correct the cause (if possible) before proceeding to the next step.
• If the fault is not visually evident, REFER to Symptom Chart or REFER to Symptom Chart: NVH .

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).

NVH symptoms should be identified using the diagnostic tools that are available. For a list of these tools, an explanation of their uses and a glossary of common terms, Glossary of Terms
REFER to: Noise, Vibration and Harshness (NVH) (100-04 Noise, Vibration and Harshness, Diagnosis and Testing).
Since it is possible any one of multiple systems may be the cause of a symptom, it may be necessary to use a process of elimination type of diagnostic approach to pinpoint the responsible system. If this is not the causal system for the symptom, REFER to: Noise, Vibration and Harshness (NVH) (100-04 Noise, Vibration and Harshness, Diagnosis and Testing).
for the next likely system and continue diagnosis.

Additional diagnostics may be necessary to further isolate the concern. An electronic listening tool such as Chassis Ear® may be used. Follow the tool manufacturer’s instructions and the Possible Sources found in the following NVH chart to determine the connection points.

Pinpoint Tests

Vehicle Drifts, Pulls

Diagnostic Overview

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).

Possible Causes

• Unevenly loaded vehicle
• Tire pressure
• Tire forces
• Brake drag
• Incorrect vehicle alignment
• Bent/damaged vehicle components
• Steering system

Component Tests

Ball Joint Inspection

1. Prior to inspecting the ball joints for wear, inspect the wheel bearings and wheel hubs.
   REFER to: Noise, Vibration and Harshness (NVH) (100-04 Noise, Vibration and Harshness, Diagnosis and Testing).

1. NOTE: In order to obtain accurate measurements, the suspension must be in full rebound with the weight of the vehicle supported by the frame.

   Raise and support the vehicle by the frame to allow the wheels to hang in the rebound position.
   

1. Inspect the ball joint and ball joint boot for damage.
   
   • If the ball joint or ball joint boot is damaged, install a new lower ball joint as necessary.
     REFER to: Lower Ball Joint (204-01A Front Suspension - LHD RWD, Removal and Installation).
     REFER to: Lower Ball Joint (204-01B Front Suspension - LHD 4WD, Removal and Installation).
     vehicles.
     

NOTE: Carry out Steps 4 through 6 to inspect the lower ball joint. Carry out Steps 7 through 9 to inspect the upper ball joint.

1. NOTICE: Do not use any tools or equipment to move the wheel and tire assembly or suspension components while checking for relative movement. Suspension damage may occur. The use of tools or equipment will also create relative movement that may not exist when using hand force. Relative movement must be measured using hand force only.

   NOTE: The weight of the wheel and tire assembly must be overcome to obtain an accurate measurement on the dial indicator.

   Inspect the ball joint for relative movement by alternately pulling downward and pushing upward on the lower control arm by hand. Note any relative vertical movement between the wheel knuckle and lower control arm at the lower ball joint.
   
   • If relative movement is not felt or seen, the ball joint is OK. Do not install a new lower ball joint.
     
   • If relative movement is found, continue with Step 5.
     

1. NOTE: In order to obtain an accurate measurement, the dial indicator should be aligned as close as possible with the vertical axis (center line) of the ball joint.

   To measure ball joint deflection, attach a suitable dial indicator with a flexible arm between the lower control arm and the wheel knuckle or ball joint stud.
   

1. Measure the ball joint deflection while an assistant pushes up and pulls down on the lower control arm, by hand.
   
   • If the deflection exceeds the specification, a new lower ball joint must be installed.
     REFER to: Lower Ball Joint (204-01A Front Suspension - LHD RWD, Removal and Installation).
     REFER to: Lower Ball Joint (204-01B Front Suspension - LHD 4WD, Removal and Installation).
     vehicles.
     
   • If the deflection meets the specification, continue with the procedure.
     

1. NOTICE: Do not use any tools or equipment to move the wheel and tire assembly or suspension components while checking for relative movement. Suspension damage may occur. The use of tools or equipment will also create relative movement that may not exist when using hand force. Relative movement must be measured using hand force only.

   Inspect the ball joint for relative movement by alternately pulling downward and pushing upward on the upper control arm by hand. Note any relative vertical movement between the wheel knuckle and upper arm at the upper ball joint.
   
   • If relative movement is not felt or seen, the ball joint is OK. Do not install a new ball joint.
     
   • If relative movement is found, continue with Step 8
     

1. NOTE: In order to obtain an accurate measurement, the dial indicator should be aligned as close as possible with the vertical axis (center line) of the ball joint.

   To measure ball joint deflection, attach a suitable dial indicator with a flexible arm between the upper control arm and the wheel knuckle or ball joint stud.
   

1. Measure the ball joint deflection while an assistant pushes up and then pulls down on the upper control arm, by hand.
   
   • If the deflection exceeds the specification, a new upper arm must be installed.
     REFER to: Upper Arm (204-01A Front Suspension - LHD RWD, Removal and Installation).
     REFER to: Upper Arm (204-01B Front Suspension - LHD 4WD, Removal and Installation).
     vehicles.
     
   • If the deflection meets or is below the specification, no further action is required.