Keep in mind the wind and the road conditions

Test the vehicle, going in both directions, on a flat road.

Front end misaligned

Adjust to specifications. Refer to Wheel Alignment Measurement in Wheel Alignment.

Unbalanced steering gear valve (if this is the cause, steering effort will be very light in direction of lead and heavy in the opposite direction)

Replace the gear valve.

Steering shaft rubbing the inside diameter of the shaft tube

Align or replace the steering column.

Low or uneven tire pressure

Inflate the tires to the recommended pressure. Refer to Tire Inflation Description in Tires and Wheels.

Front or rear brakes dragging

Adjust the brakes.

Broken or sagging front spring

Replace the spring. Refer to Front Coil Springs Replacement or Leaf Springs Replacement in Front Suspension.

Incorrect front wheel alignment (camber)

Check and align the front suspension. Refer to Wheel Alignment Measurement in Wheel Alignment.