How save some money and be sure that your alignment is spot on.
This method describes the process of doing a 4-wheel alignment on your car. This will allow you to set camber, tracking, and toe. Using this procedure you will set toe on all 4 wheels individually and with respect to the chassis centreline. This means that your thrust angle (tracking) will also be correct when you are finished. Caster is not generally adjustable and the procedure assumes that subframes and unibody are square and true. If your chassis is damaged "out of true" the procedure will still work, but your thrust angle may be incorrect. You may also use this method to set thrust angle and toe even if you do not intend to change camber. The order of the procedure is important, so follow the steps. Please note that an alignment is required any time that you change any parameter or component in the suspension, with the exception of sway bars. If you don't align afterwards you will have driveability issues, uneven and/or excessive tyre wear, and possible reduced fuel economy.
This method has been used for many decades, and is still used by some racing teams.
* camber gauge (optional)
* 7' straight edge (can be straight lumber)
* (4) jack stands
* (2) 10' lengths of 3/4" or 1" metal electrical conduit
* (4) 12"x12"x2" concrete block (optional, but highly suggested)
* (16-20) 12"x12"x1/8" commercial floor tiles
* a couple of 12"x12" pieces of plywood (optional)
* string (fishing line works great)
* (4) axle stands
* hydraulic jack
* steering wheel locking device (highly suggested)
* 6" or 12" rule with 32nd or 64th gradations
* 3-4 hours for your first time, includes initial setup
* 45 minutes to an hour with experience
Make slide plates for each wheel by putting grease between two 12"x12" floor tiles.
Measure 2 feet in from the edge of the metal conduit and drill a small hole through the conduit. Make sure to drill through both walls. Later you will feed the string through these holes and tie it off.
Step 1: Level Your Work Area
Park your car on a flat, level surface. Jack car up and support with jack stands. The car must be high enough to place concrete blocks, slip plates, and a few levelling shims (if required) under each wheel. We are using the 2" thick concrete blocks to raise the car off the ground just enough so that you can easily get to the adjustment turnbuckles later.
Now slide the concrete blocks under the tyres. Measure for level from left to right, front to back, and shim accordingly.
When everything is levelled, place the slide plates that you previously made beneath each wheel (on top of the concrete blocks and levelling shims). Starting with either the front or rear of the car, remove the jack stand and slowly lower the car onto the slide plates.
CAUTION! It is possible for the car to slide across the plates and to slip off of the concrete blocks. Take your time and pay attention to what you are doing. I cannot be held liable for carelessness.
At this point all four tyres of the car should be resting on the slide plates.
Step 2: Centre and Immobilize Steering Wheel
Centre the steering wheel where you want it. Notice the slide plates will move as you turn the steering wheel. The slide plates that you made also allow the suspension to “settle” into its natural state. Once centred, it is suggested that you immobilize the steering wheel.
After you have locked the steering wheel give a light tug outward on the front of each wheel. If you have any play in the tie-rods this will take it up and place the wheel in the position is would be in when loaded by driving.
Step 3: Check Camber
This step, while optional, is recommended. With the stock suspension components there is limited adjustability. The suspension components that you have will determine the method of camber adjustment. There are many variations of suspension components; stock, aftermarket struts and springs, camber kits, and coilovers. For the sake of simplicity we will only discuss camber measurement, and the benefits and detriments of camber, not adjustment.
Because we carefully levelled the car previously, a less expensive type of camber gauge may be used. There are digital camber gauges on the market that will allow you to check camber while the car is not level.
Positive camber is when the top of the wheel leans outward from the car. Negative camber is when the top of the wheel leans inward.
You want to be careful with the amount of camber that you introduce. Negative camber, especially on the front wheels will help with grip while cornering, because the tyre on the outside of the turn will have a larger contact patch while cornering. However, camber (negative or positive) will decrease straight line stability and impair braking because as the tyre leans in or out the contact patch is reduced. Note: Most race cars rarely use more than -3 degrees of camber. A little bit of negative camber on the rear wheels will also help with grip while cornering. However, some like to have the rear of the car loose while cornering. In this case you would reduce the amount of negative camber, and possibly introduce a little positive camber. If you do not intend to race your car, then the manufacturer's recommended camber settings should be used.
Step 4: String it up!
Set 1 jack stand at each corner of the car as shown below. Rest conduit across jack stands left to right. Thread string through holes previously drilled in conduit, and tie off at both ends. For string, I use a neon yellow Dacron fly fishing line (20 lb. Test). It is highly visible, is very good for this application, and costs are negligible. You may need to use some kind of needle to thread the string through the conduit. Take up the slack in the string so that it doesn't sag, but don't pull it too tight.
Square it up! Now use your rule to measure the distance from the hub to the string. You need to move the jack stands and conduit until the distance from the hub to the string is equidistant. The measurements for the front wheels will be different than that of the rear, but still need to be equidistant. In other words, the distance between the hub of the driver's side front wheel and the string must be equivalent to the distance between the hub of the passenger's side front wheel and the string. This measured distance may not be the same for the rear wheels, but the distance from the hub of the driver's side rear wheel to the string must equal the distance between the hub of the passenger's side rear wheel and the string. This will take a little while to get set up. You need to measure all four wheels each time you move the string. Note the conduit helps here because when you move one side the opposite side moves the equivalent distance. Measure, repeat, measure, repeat, and so on until its all square. Once the string is squared, don't move it! If you move the string, bump into the jack stands, conduit, etc... You will have to set it up all over again. This is particularly important later on when you are crawling under the car to make adjustments.
Step 5: Measure and Set Toe, and Tracking
Toe is arguably the most important suspension setting. Very small amounts of toe can drastically affect the driveability of the car and tyre life. Toe-out is when the front of the tyres are pointing away from each other as viewed from above the car, and toe-in is when the front or the tyres are pointing toward each other. A small amount of toe-out can improve the way a car enters the turn, but will decrease straight line stability. Whereas toe-in will make it harder for the car to turn and generally increase straight line stability.
Now that the string is squared up around the car, and you have previously locked the steering wheel in place you are ready to measure for toe. Measure from the edge of the rim at the font of wheel to the string and record the measurement. Then measure from the edge of the rim at the back of the wheel to the string and record the measurement. If the wheel is closer to the string at the front than it is at the back then you have toe-out. If the back of the wheel is closer to the string then you have toe-in. To find the amount of toe, simply subtract the smaller of the recorded measurements from the larger. Note: you may measure from the back of the rim first if you wish. It doesn't matter in the order you do this, but try to be consistent to avoid errors.
Now that you have determined toe, you may need or want to make adjustments. To adjust toe on the front wheels, loosen the lock nut on the tie rod. Hold the ball end to avoid damaging it. Then adjust by turning the hex part of the tie rod. I don't recall which way to turn for toe-in versus toe-out, but it is not important. If it is going the wrong way, turn it the opposite direction. Generally adjust the tie rod a ½ turn, then measure toe. Continue to adjust and measure until you get the toe setting that you want. Then tighten the lock nut. Note: You will want to set the toe on the driver’s side the same as the toe on the passenger's side. This will ensure proper tracking (more about this later). Also, remember that you set toe on each side for ½ of total toe. For example if you want 1/8” of toe-out on the front wheels, you would set each wheel at 1/16” toe-out.
The process for measuring and setting toe for the rear wheels is the same as the front with the exception of the adjustment point. The adjustment mechanism for the rear wheels is on the aft suspension arm. Loosen the lock nut then turn the adjuster. Follow the procedure from above. When toe is set where you want it, tighten the lock nuts.
Finally, an additional benefit to the string method of alignment is that once you have set toe according to the previous instructions, the four wheel tracking will be correctly set. Because the string is “square” around the car, and because you are setting equivalent amounts of toe on the driver's and passenger's sides all toe settings are centred on the centerline of the chassis. Therefore when you drive down a straight, flat road and hold the steering wheel centred, the car will track straight.
BTW I have a camber gauge if you need it.