Alignment for 1998 4runner ltd, stock suspension.
12-04-2017, 10:40 AM
#1
Alignment for 1998 4runner ltd, stock suspension.
I replaced some parts on my suspension, and I knew the alignment was way off. I had done alignments years ago in school, and seeing all the diy videos out there gave me the refresher I needed. Lots of people use string and plumb-lines, and if you are patient, measure carefully and use a calculator, this will get you very, very close. It might take you all day though. A few tools can speed this up.
Here is the quick alignment I used:
Make sure the cams turn freely, and center them pointing straight up. Move the car at least 10ft to settle everything, and park on a level spot for the two front tires. The side-to-side level is more important than back-to-front. Using an old-fashioned bubble level held vertical next to each tire, adjust each pair of cams equally to get each wheel close to vertical (zero camber). After each adjustment, re-settle the suspension. At this point adjust toe-in using a 6ft piece of 1x1 with two vertical paint sticks clamped to it. Compare this "gauge" against the center of tread (or a mark) at the front & back of the tires. Adjust both tie rods in or both out for equal distance (zero toe). Adjust one in and one out to center the steering wheel. You can now drive to the alignment shop or do an even better job.
This quick alignment was fine, but I wanted to check the caster. Or maybe I just wanted a reason to buy a cool digital level, and build a wheel jig. I made my $20 jig out of 3/4" aluminum tubing, some JB weld, stainless screws, and a short bungie to hold it on the wheel. I glued up my jig on a flat board, and used the digital level and a plate glass shower door to calibrate the jig flatness. The jig adjusting screws rest on the flat face of my rims just inside the outer lip. My $40 digital level (with "LAZER") has a tripod mounting hole, and I used this to clamp it to the jig.
A digital level lets you measure angles directly without stopping to work the calculator or waiting for the plumb line to stop swinging. By default, mine has a graphic to show which side of 90deg you are on, but it also has a "reference" or "zero" mode that shows absolute angle from any starting point. This can reduce caster to one measurement.
Using these new tools, I found that the camber setting I had done with the bubble level was already within spec. This is not surprising, since even a 1/8" difference on a 16" wheel is less than 1/2 degree angle. It isn't hard to do better.
I measured caster using a piece of signboard marked with a bisected 40deg angle (20deg right, 20deg left). I centered this under one front tire with a couple sheets of plastic and a smear of grease underneath, so the signboard would turn with the tire and not rip. With a helper in the vehicle, the tire was first turned outward 20deg and the engine shut off (the digital level would not measure accurately with the engine running). The tire rotates a bit, so the wheel jig must be spun back close to vertical and the camber angle measured. Repeat with the tire turned inward 20deg. You want the total change in camber (delta). If your camber was originally set near zero, turning the tire outward will also lean the tire outward (add positive camber), and turning the tire inward will lean the tire inward (add negative camber). This might not be true if your car is jacked, but just use common sense to calc the delta camber. My angles were 1.1deg pos, 0.7deg neg for a delta of 1.8deg. Multiply by 1.5 (magic number for a 40deg sweep) to get 2.7deg caster, well within spec.
When I repeated for the other tire, the caster was 4.0, a bit too much. To reduce caster, push the front of the control arm outward and/or pull the rear of the control arm inward. It only took a very small adjustment. The last adjustment is always toe-in. Since I had tweaked my settings very little, the toe-in off only a bit. I will re-check at the next oil change. With the tools it should take 30min max.
There are lots of alignment videos, mostly bad ones. One that takes forever but actually shows adjustments:
Here is the quick alignment I used:
Make sure the cams turn freely, and center them pointing straight up. Move the car at least 10ft to settle everything, and park on a level spot for the two front tires. The side-to-side level is more important than back-to-front. Using an old-fashioned bubble level held vertical next to each tire, adjust each pair of cams equally to get each wheel close to vertical (zero camber). After each adjustment, re-settle the suspension. At this point adjust toe-in using a 6ft piece of 1x1 with two vertical paint sticks clamped to it. Compare this "gauge" against the center of tread (or a mark) at the front & back of the tires. Adjust both tie rods in or both out for equal distance (zero toe). Adjust one in and one out to center the steering wheel. You can now drive to the alignment shop or do an even better job.
This quick alignment was fine, but I wanted to check the caster. Or maybe I just wanted a reason to buy a cool digital level, and build a wheel jig. I made my $20 jig out of 3/4" aluminum tubing, some JB weld, stainless screws, and a short bungie to hold it on the wheel. I glued up my jig on a flat board, and used the digital level and a plate glass shower door to calibrate the jig flatness. The jig adjusting screws rest on the flat face of my rims just inside the outer lip. My $40 digital level (with "LAZER") has a tripod mounting hole, and I used this to clamp it to the jig.
A digital level lets you measure angles directly without stopping to work the calculator or waiting for the plumb line to stop swinging. By default, mine has a graphic to show which side of 90deg you are on, but it also has a "reference" or "zero" mode that shows absolute angle from any starting point. This can reduce caster to one measurement.
Using these new tools, I found that the camber setting I had done with the bubble level was already within spec. This is not surprising, since even a 1/8" difference on a 16" wheel is less than 1/2 degree angle. It isn't hard to do better.
I measured caster using a piece of signboard marked with a bisected 40deg angle (20deg right, 20deg left). I centered this under one front tire with a couple sheets of plastic and a smear of grease underneath, so the signboard would turn with the tire and not rip. With a helper in the vehicle, the tire was first turned outward 20deg and the engine shut off (the digital level would not measure accurately with the engine running). The tire rotates a bit, so the wheel jig must be spun back close to vertical and the camber angle measured. Repeat with the tire turned inward 20deg. You want the total change in camber (delta). If your camber was originally set near zero, turning the tire outward will also lean the tire outward (add positive camber), and turning the tire inward will lean the tire inward (add negative camber). This might not be true if your car is jacked, but just use common sense to calc the delta camber. My angles were 1.1deg pos, 0.7deg neg for a delta of 1.8deg. Multiply by 1.5 (magic number for a 40deg sweep) to get 2.7deg caster, well within spec.
When I repeated for the other tire, the caster was 4.0, a bit too much. To reduce caster, push the front of the control arm outward and/or pull the rear of the control arm inward. It only took a very small adjustment. The last adjustment is always toe-in. Since I had tweaked my settings very little, the toe-in off only a bit. I will re-check at the next oil change. With the tools it should take 30min max.
There are lots of alignment videos, mostly bad ones. One that takes forever but actually shows adjustments:
Last edited by tns1; 12-04-2017 at 10:58 AM.
