Caster angle is an important part of a good alignment. The Honda Civic, like other cars, has a pivot point on the wheels that turn to steer the car. The angle of that pivot point is the degrees of caster. A tilt toward the front of the car is negative caster, while a tilt to the rear is positive caster. Measuring caster takes only a few tools, and can be done in a day. Not all Honda Civics have the capability of adjusting the caster. Check the service manual for your particular Civic for more information.
Determine the correct caster angle for your particular Honda Civic. For instance, the 2006-2010 Honda Civic DX, DX-G, GX, LX, EX, or Si with a 15, 16, or 17-inch wheel requires a caster angle of seven degrees, with an accepted tolerance of plus or minus one degree.
Secure the caster gauge to the right front wheel of the car. Turn the steering wheel to the right until the wheel with the gauge has turned 20 degrees.
Ensure that the gauge is level. Set the adjustable caster bubble to zero on the gauge.
Rotate the steering wheel to the left, until the wheel with the gauge is 20 degrees past center. Check the gauge to make sure it is level, then look at the location of the bubble. This is the amount of caster angle for this wheel. Write this number down and keep it handy for later, when you are ready to adjust the caster.
Repeat these steps for the left front wheel.
Compare the two caster readings. If the car's caster can be adjusted, loosen the upper ball joint with a socket and driver until it can move freely in its mounting bracket. Slide the ball joint forward to negative caster and to the rear of the car for positive caster angle.
