I completed a DIY 4 wheel alignment this summer, front toe/caster and rear toe/camber. There was some discussion in a thread I started here:
http://dmctalk.org/showthread.php?18...specifications
That thread kept going off the rails and I never went in to details of methods.
What I used:
-A car mounted strings fixture. This seems like the only rational way to do strings, I can't imagine setting up a box and expecting the car to never move.
-Some 3D printed fixtures I made that attach to the wheels & hold engineering rulers in place (helps center the strings faster)
-Some laser printed angle guides for caster
-A water level
-Some wheel cribs to help level and adjustments easier
-4x cheap cutting boards for turn plates
-Angle aluminum and engineering rulers to make tires that were "virtually larger" for more precise degree measurements. Was able to measure over about 39" rather than just the wheel widths.
What I struggled with most was repeatability of caster measurements. The angle guides & a carpenter laser improved that situation immensely.
The end results are really good. Car tracks straight with equalized caster, and with a little less than stock toe-in (.22 deg front, .15/.18 rear) the handling leads pleasantly and predictably towards neutral. With the shims on the rear, removing a shim was going to push it past the target toe-in, so erred on the side of less rather than more.