Here's how we align the rear of our shop cars:
The rear camber on the left and right sides should be the same before completing the following steps. We run around 1.5 degrees of negative camber per side at the rear of our cars for street use (at the track you'll want more). We measure camber with a digital angle finder that has magnets on the side: https://www.amazon.com/AccuRemote-Digital-Electronic-Magnetic-Protractor/dp/B006JR8XBG
We zero the angle finder to the top of the main hoop. Then we stick the angle finder against the side of the rear rotors to find the camber angle. We look for 1.5 degrees. To adjust the camber you have to loosen the knuckle to strut bolts. On stock struts you will also have to slot one of the strut holes to give you some adjustment.
After you have the camber set, you can move on:
The next thing we do is make sure the rear tires are toed in or out the same amount. This makes sure that as you drive down the road, the rear tracks in line with the front. Picture a car that has the left rear toed in and the right rear toed out. The car would "crab" or "dog track" down the road with the rear of the car jutting out to the right compared to the front of the car.
We check this with a long level or straight edge, tape measure and some blocks of wood. First we place the level against one of the rear tires with the level extending out in front of the tire.
Use wood blocks to space the level up to where it can bridge across the tire/wheel. Use the same number of blocks at the front of the level so that it is flat to the ground.
Measure from the lower frame rail to the outer edge of the level. Write down this measurement.
Repeat this process on the other side of the car. Be sure to measure to the same point on the frame rail (as you move forward and back your number will change). You can also measure to the tunnel if you don't have side panels installed.
Also, make sure you measure to the outside of the level again. Write down this measurement.
You shouldn't be too concerned with the actual value of the measurement. What is important is that the two measurements are equal. Once they are equal, you'll know that the rear tires are centered with the rest of the car and it won't drive down the road with the rear end offset to one side.
It doesn't matter which side you adjust to make the numbers equal. Just adjust either of the rear toe rods until the measurements are equal. Be sure to double check the measurements on both sides before moving on.
With the rear tires now centered up, it is time to set the rear toe. From now on, any adjustment you make will be done to both sides of the car. If you only adjust one side, your rear tires will no longer be aimed the same.
The easiest way measure toe is with a set of toe plates: https://www.amazon.com/Longacre-LON52-79501-Toe-In-Plate/dp/B000VAOHB2
Place one plate on the outside of each tire and stretch both of the tape measures across. One of the plates has magnets on it to hold the hook end of the tape measures so be sure to loop the hooks into that plate.
Compare the measurements between the front and rear tape measures. The rear toe is normally measured in degrees but since the Longacre toe plates are a consistent length, we just shoot for 1/8" toe in. This means you'll want the front tape measure to show 1/8" less than the rear tape measure.
To adjust the toe, you'll need to tighten or loosen the rear toe rods. If the number on the front tape is more than 1/8" under the rear, you'll need to tighten the toe rods so that they screw into the rod ends. If the number is larger in the front than it needs to be, you'll loosen the toe rods our of the rod ends. Remember to make the same adjustment to both sides.
To make it easier to keep track of the adjustments, we like to stick a piece of masking tape on each toe rod and put a sharpie mark straight up on top of the rod. From that point on, every adjustment we make is based off of how far we've turned that mark. If the measurements are far from where we need them to be we'll turn 1 or more full rounds on both sides. If it isn't too far off, we'll turn half a round on both sides.
If you haven't tightened the jam nut you can start making adjustments with a 13mm wrench. Obviously if you've tightened the jam nut you'll need to loosen it to make adjustments.
After each adjustment, we either roll the car back and forth a few inches or we bounce the rear suspension up and down just to make sure everything is settled out. When you remeasure the toe after each adjustment, make sure the plates are sitting flat all the way up against the tires. As you adjust the toe rods, the tires will steer away from the toe plates so you'll need to push them back against the tires.
Once the front tape measure reads 1/8" under the rear, tighten the jam nuts against the rod ends.
Read the front end alignment thread next: http://dfkitcar.com/forum/index.php?threads/diy-front-end-alignment.751/
The rear camber on the left and right sides should be the same before completing the following steps. We run around 1.5 degrees of negative camber per side at the rear of our cars for street use (at the track you'll want more). We measure camber with a digital angle finder that has magnets on the side: https://www.amazon.com/AccuRemote-Digital-Electronic-Magnetic-Protractor/dp/B006JR8XBG
We zero the angle finder to the top of the main hoop. Then we stick the angle finder against the side of the rear rotors to find the camber angle. We look for 1.5 degrees. To adjust the camber you have to loosen the knuckle to strut bolts. On stock struts you will also have to slot one of the strut holes to give you some adjustment.
After you have the camber set, you can move on:
The next thing we do is make sure the rear tires are toed in or out the same amount. This makes sure that as you drive down the road, the rear tracks in line with the front. Picture a car that has the left rear toed in and the right rear toed out. The car would "crab" or "dog track" down the road with the rear of the car jutting out to the right compared to the front of the car.
We check this with a long level or straight edge, tape measure and some blocks of wood. First we place the level against one of the rear tires with the level extending out in front of the tire.
Use wood blocks to space the level up to where it can bridge across the tire/wheel. Use the same number of blocks at the front of the level so that it is flat to the ground.
Measure from the lower frame rail to the outer edge of the level. Write down this measurement.
Repeat this process on the other side of the car. Be sure to measure to the same point on the frame rail (as you move forward and back your number will change). You can also measure to the tunnel if you don't have side panels installed.
Also, make sure you measure to the outside of the level again. Write down this measurement.
You shouldn't be too concerned with the actual value of the measurement. What is important is that the two measurements are equal. Once they are equal, you'll know that the rear tires are centered with the rest of the car and it won't drive down the road with the rear end offset to one side.
It doesn't matter which side you adjust to make the numbers equal. Just adjust either of the rear toe rods until the measurements are equal. Be sure to double check the measurements on both sides before moving on.
With the rear tires now centered up, it is time to set the rear toe. From now on, any adjustment you make will be done to both sides of the car. If you only adjust one side, your rear tires will no longer be aimed the same.
The easiest way measure toe is with a set of toe plates: https://www.amazon.com/Longacre-LON52-79501-Toe-In-Plate/dp/B000VAOHB2
Place one plate on the outside of each tire and stretch both of the tape measures across. One of the plates has magnets on it to hold the hook end of the tape measures so be sure to loop the hooks into that plate.
Compare the measurements between the front and rear tape measures. The rear toe is normally measured in degrees but since the Longacre toe plates are a consistent length, we just shoot for 1/8" toe in. This means you'll want the front tape measure to show 1/8" less than the rear tape measure.
To adjust the toe, you'll need to tighten or loosen the rear toe rods. If the number on the front tape is more than 1/8" under the rear, you'll need to tighten the toe rods so that they screw into the rod ends. If the number is larger in the front than it needs to be, you'll loosen the toe rods our of the rod ends. Remember to make the same adjustment to both sides.
To make it easier to keep track of the adjustments, we like to stick a piece of masking tape on each toe rod and put a sharpie mark straight up on top of the rod. From that point on, every adjustment we make is based off of how far we've turned that mark. If the measurements are far from where we need them to be we'll turn 1 or more full rounds on both sides. If it isn't too far off, we'll turn half a round on both sides.
If you haven't tightened the jam nut you can start making adjustments with a 13mm wrench. Obviously if you've tightened the jam nut you'll need to loosen it to make adjustments.
After each adjustment, we either roll the car back and forth a few inches or we bounce the rear suspension up and down just to make sure everything is settled out. When you remeasure the toe after each adjustment, make sure the plates are sitting flat all the way up against the tires. As you adjust the toe rods, the tires will steer away from the toe plates so you'll need to push them back against the tires.
Once the front tape measure reads 1/8" under the rear, tighten the jam nuts against the rod ends.
Read the front end alignment thread next: http://dfkitcar.com/forum/index.php?threads/diy-front-end-alignment.751/
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