Lean Correction

Front and rear lean correction

NOTE: When verifying the vehicle lean, all tires must be inflated to the proper 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.

Inspect all 4 tires for proper inflation, adjust as necessary.
- Refer to the Safety Certification sticker located on driver door jamb.
With the vehicle in NEUTRAL, position it on a hoist. For additional information, refer to JACKING & LIFTING .

NOTE: The front and rear springs must be in proper working order before a vehicle lean condition can be properly diagnosed.

Inspect the front and rear springs for any signs of damage (fractured or broken).
1. If a spring is damaged, replace the 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.
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 Vehicle Ride Height
Courtesy of FORD MOTOR CO.
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.
Measure chassis ride height and record the measured values. For additional information, refer to SUSPENSION SYSTEM .
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.
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

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
0 to 5/8 in. (16 mm)	N/A	No action to be taken
Greater than 5/8 in. (16 mm)	Less than 5/8 in. (16 mm)	No chassis correction authorized, investigate frame and body systems
Greater than 5/8 in. (16 mm)	5/8 in. and greater (16 mm and greater)	Replace spring

Remove the high side front coil spring. For additional information, refer to FRONT SUSPENSION .
Compare the height of the original front coil spring with a new one with the same part number. Note the difference.
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 .
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 .
Compare all 3 front coil springs and select the 2 most evenly matched for installation.
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 .

Rear lean correction

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
0 to 3/4 in. (19 mm)	N/A	No action to be taken
Greater than 3/4 in. (19 mm)	Less than 3/4 in. (19 mm)	No chassis correction authorized, investigate frame and body systems
Greater than 3/4 in. (19 mm)	3/4 in. to 1 in. (19 to 25 mm)	Install shim 3C4Z-5A300-AA on low side of vehicle
Greater than 3/4 in. (19 mm)	Greater than 1 in. to 1-1/2 in. (25 to 38 mm)	Install shim 5C3Z-5742-AA on low side of vehicle
Greater than 3/4 in. (19 mm)	1 1/2 in. and greater (38 mm and greater)	Replace spring

If shim installation is required, continue with this procedure.

Support the axle.

Fig 2: Supporting Axle
Courtesy of FORD MOTOR CO.
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.
Turn the shim so the recess is facing upward.

Fig 4: Identifying Shim
Courtesy of FORD MOTOR CO.
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: Inserting Shim Between Rear Spring & Spring Seat
  Courtesy of FORD MOTOR CO.
Install 2 new U-bolts and 4 new nuts.
- For E-150, tighten to 115 Nm (85 lb-ft).
- For F-250 - F-450, tighten to 175 Nm (129 lb-ft).
  
  Fig 6: Locating Nuts And U-Bolts
  Courtesy of FORD MOTOR CO.
Remove the support from the axle.