Vehicle Leads/Pulls Procedure
| • | Inspect for mismatched or uneven tires. |
| • | Inspect for broken or sagging springs. |
| • | Inspect for radial tire lateral force. |
| • | Inspect the wheel alignment |
| • | Inspect for dragging of the front brake. |
| • | Inspect for high friction in the ball joints or the strut mounts. |
| • | Inspect for unbalanced pinion and valve. |
Vehicle Leads/Pulls Diagnosis
Lead/Pull is the deviation of the vehicle from a straight path, on a level road with no pressure on the steering wheel.
Lead/Pull is generally caused by:
| • | A misconstructed tire. |
| • | An uneven brake adjustment. |
| • | A misaligned wheel. |
The way in which a tire is built can produce lead in a vehicle. An example of this is placement of the belt. Off-center belts on radial tires can cause the tire to develop a side force while rolling straight down the road and the tire will tend to roll like a cone.
The Radial Tire Lead/Pull Correction chart in this section should be used in order to ensure that the front wheel alignment is not mistaken for tire lead. Rear tires will not cause lead.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Adjust the tire pressure to specifications. Check for proper trim heights. Check brakes for drag. Are the checks complete? | -- | -- | |
2 | Road test the vehicle. Does the vehicle still lead or pull? | -- | System OK | |
3 | Cross switch the front tire and wheel assemblies. Does the vehicle still lead or pull? | -- | System OK | |
4 | Road test the vehicle. Does the vehicle still lead or pull in the same direction? | -- | ||
5 | Check front wheel alignment. Adjust front wheels to proper alignment. Does the vehicle still lead or pull in the same direction? | -- | ||
6 | Check caster-camber toe for proper alignment. Is the caster-camber toe improperly aligned? | -- | ||
7 | Align the caster-camber toe. Does the vehicle still lead or pull? | -- | System OK | |
8 | Road test the vehicle. Does the vehicle lead or pull in the opposite direction? | -- | System OK | |
9 | Swap the left front tire and wheel assemblies with the left rear tire and wheel assemblies. Does the vehicle still lead or pull in the opposite direction? | -- | System OK | |
10 | Swap the right front tire and wheel assemblies with the right rear tire and wheel assemblies. Does the vehicle still lead or pull in the opposite direction? | -- | System OK | |
11 | Change the camber setting. Does the vehicle still lead or pull? | -- | System OK | |
12 | If the vehicle leads or pulls to the left, add an additional -0.5° camber on the left and +0.5° camber on the right. If the vehicle leads or pulls to the right, add an additional +0.5° camber on the left and -0.5° camber on the right. Does the vehicle still lead or pull? | -- | System OK | |
13 | If the vehicle leads or pulls to the left, increase (-) camber on the left and (+) camber on the right until pull is eliminated. If the vehicle leads or pulls to the right, increase (+) camber on the left and (-) camber on the right until pull is eliminated. Does the vehicle still pull? | -- | -- | System OK |
