DIY Front End Alignment


DIY Front End Alignment



To most people, front end alignment is some kind of voodoo science better left to professionals.  Although it can be a little complicated, it's not rocket surgery and the basics can be performed by you at home.  At least well enough to drive to an alignment shop after you've done the front suspension or steering linkage work.  Of course, accurate alignment is important for proper handling and tire wear.  Here's how to get it close enough to drive.  Please note all measurements are with the car on the ground at normal ride height.

The hardest to correctly measure is caster.  Although some crude instruments are available, it's probably better left to a professional with proper equipment and training to set this.  Caster is the amount of frontward or backward tilt an imaginary line drawn through the upper and lower ball joints of each wheel would have. Backward tilt is positive caster and frontward tilt is negative caster.  Zero is perfectly vertical.  Some positive caster is desireable as it helps a vehicle to track straight, although factory specs for Chevelles are close to zero.  The more shims added to the rear upper A arm mount and/or removed from the front, the more positive caster is increased.  If you duplicated the same difference in front to rear shipm thickness as it had before you disturbed it, you should be close.

Camber is the amount of tilt in or out at the top a wheel has. It is more easily measured (the factory spec is zero to 1/2 degree positive).  With positive camber the wheel tilts outward at the top, negative in at the top.  To check it, use a level with some wood shims taped to it at the proper locations so it only contacts the rim vertically at the top and bottom.  Contacting the tire isn't accurate because of the tire bulge at the bottom.  Remove or add shims equally to both upper A arm mounts for each wheel until the wheel is perfectly vertical or just a hair tilted out.  Having camber or caster perfect isn't real important just to drive to the alignment shop.

Toe is important.  You must have a slight amount of toe-in or the car will want to go anywhere but straight.  It's the most critical adjustment but the easiest to adjust.  Toe is the difference in measurement between the center of the very front of the tires vs. the center of the very back of the tire.  Factory spec is 1/8" to 1/4" toe in.  In other words, the front of the tires should be closer together than the rear.  There are many ways to measure but the easiest is to take two straight edges, such as metal yard sticks, and place them horizontally level against the sidewalls of the tires about 4"-6" above the ground.  Be sure to not contact sidewall lettering, etc.  To adjust, loosen the 4 clamps on the tie-rod sleeves and the sleeves to draw the tie rod ends together or spread apart.  It will take some trial and error.  Be sure to tighten the 4 sleeve clamps when adjustments are completed.  You can also use this method to center the steering wheel.

If you're adventurous, you can buy some basic tools and get more precise to utilize your own alignment permenantly as I did.  The best bet though is to just use it temporarily until you get to an alignment shop.