Lean Correction

Front and rear lean correction 

NOTE: When verifying the vehicle lean, all tires must be inflated to the correct specifications and all equipment must be removed from the vehicle, such as tool boxes, caps, bed fuel tanks, etc. The vehicle must also be parked on a level surface.
1. Inspect all 4 tires for proper inflation, adjust as necessary.
   • Refer to the Safety Certification sticker located on driver door jamb.
2. With the vehicle in NEUTRAL, position it on a hoist. For additional information, refer to JACKING AND LIFTING article.
NOTE: The front and rear springs must be in correct working order before a vehicle lean condition can be correctly diagnosed.
3. Inspect the front and rear springs for any signs of damage (fractured or broken) in the following sequence.
   1. If a spring is damaged, install a new spring and re-evaluate the vehicle. If this corrects the lean condition, no further action is necessary.
   2. If the lean condition is not corrected, proceed to Step 4.
4. With the vehicle on a level surface and the suspension at curb height, measure the vehicle ride height from the wheel lip to the top of the wheel well opening at all 4 corners. Record the measured values.
Fig 1: Measuring From The Wheel Lip To The Top Of The Wheel Well
Courtesy of FORD MOTOR CO.
5. For the front measurements, take the smaller measured value and subtract it from the larger measured value, this is the wheel well difference number. Record this number.
   • Repeat the calculation using the rear measurements.
6. Measure chassis ride height and record the measured values. For additional information, refer to Ride Height Measurement .
7. For the front measurements, take the smaller measured value and subtract it from the larger measured value, this is the chassis ride height difference number. Record this number.
   • Repeat the calculation using the rear measurements.
8. Compare the recorded front ride height difference number to the recorded rear ride height difference number.
   • If the recorded front ride height difference number exceeds that of the rear ride height difference number, correct the lean condition using the Front lean condition steps.
   • If the recorded rear ride height difference number exceeds that of the front ride height difference number, correct the lean condition using the Rear lean condition steps.

Front lean correction 

9. Using the recorded front wheel well difference numbers, the recorded front chassis ride height difference numbers and the following repair action chart, determine what repair action is needed to correct the vehicle lean condition.
   FRONT LEAN CORRECTION CHART
   
   

   Wheel Lip to Wheel Well Difference Left to Right	Chassis Ride Height Difference Left to Right	Action
   16 mm (0 to 5/8 in)	N/A	No action to be taken
   16 mm (Greater than 5/8 in)	16 mm (Less than 5/8 in)	No chassis correction authorized, investigate frame and body systems
   16 mm (Greater than 5/8 in)	16 mm and greater (5/8 in and greater)	Install a new spring

10. Remove the high side front coil spring. For additional information, refer to FRONT SUSPENSION article.
11. Compare the height of the original front coil spring with a new one with the same part number. Note the difference.
12. If the original front coil spring exceeds the height of the new spring by 13 mm (1/2 in), install the new front coil spring in the vehicle. For additional information, refer to FRONT SUSPENSION article.
13. If the original front coil spring is shorter than the new spring by at least 13 mm (1/2 in), remove the low side front coil spring from the vehicle. For additional information, refer to FRONT SUSPENSION article.
14. Compare all 3 front coil springs and select the 2 most evenly matched for installation.
15. From the 2 most evenly matched coil springs, select the tallest and install it on the lower side of the vehicle. Install the shorter of the 2 on the higher side of the vehicle. For additional information, refer to FRONT SUSPENSION article.

Rear lean correction 

16. Using the recorded rear wheel well difference numbers, the recorded rear chassis ride height difference numbers and the following repair action chart, determine what repair action is needed to correct the vehicle lean condition.
    REAR LEAN CORRECTION CHART
    
    

    Wheel Lip to Wheel Well Difference Left to Right	Chassis Ride Height Difference Left to Right	Action
    19 mm (0 to 3/4 in)	N/A	No action to be taken
    19 mm (Greater than 3/4 in)	19 mm (Less than 3/4 in)	No chassis correction authorized, investigate frame and body systems
    19 mm (Greater than 3/4 in)	19 to 25 mm (3/4 in to 1 in)	Install shim 3C4Z-5A300-AA on low side of vehicle
    19 mm (Greater than 3/4 in)	25 to 38 mm (Greater than 1 in to 1-1/2 in)	Install shim 5C3Z-5742-AA on low side of vehicle
    19 mm (Greater than 3/4 in)	38 mm and greater (1 1/2 in and greater)	Install a new spring

    • If shim installation is required, continue with this procedure.
17. Support the axle.
Fig 2: Supporting The Axle
Courtesy of FORD MOTOR CO.
18. Remove and discard the 4 nuts and 2 U-bolts to allow the rear axle to separate from the rear spring.
Fig 3: Locating Nuts And U-Bolts
Courtesy of FORD MOTOR CO.
19. Turn the shim so the recess is facing upward.
Fig 4: Turning The Shim
Courtesy of FORD MOTOR CO.
20. Insert the shim between the rear spring and the spring seat.
    • Position the shim so the center bolt through the spring leaves is in the shim recess, the stud on the bottom of the shim is in the spring seat recess and the shim is aligned with the rear spring.
Fig 5: Positioning The Shim
Courtesy of FORD MOTOR CO.
21. Install 2 new U-bolts and 4 new nuts.

    With the vehicle at curb height, tighten the U-bolt nuts evenly in an X-type pattern in 5 stages.

    • Stage 1: Tighten to 50 Nm (37 lb-ft).
    • Stage 2: Tighten to 100 Nm (74 lb-ft).
    • Stage 3: Tighten to 150 Nm (111 lb-ft).
    • Stage 4: Tighten to 200 Nm (148 lb-ft).
    • Stage 5: Tighten to 225 Nm (166 lb-ft).
Fig 6: Locating Nuts And U-Bolts
Courtesy of FORD MOTOR CO.
22. Remove the support from the axle.