I find it hard to believe that when I was using this technique,
lasers were still only experimental, so add a couple of lasers as a
possible substitute for string.
The system was designed for use on openwheeler racing cars, which
were some of the few with independent rear ends. Wheel alingnment
gear only did one end at a time. Although you could set the rear
toe in or out, you could not tell where the wheels were pointing.
It could be well out to one side.
First you require 2 string lines, using good quality builders string
line, set up parallel to each other, at axle height. They should be
about 6 inches wider apart than the with of the car. They should
extend a foot or so from the front & rear of the car, for easy
measurement.
Now drive the car between the lines, or set them up around the car.
The car must be parrell to the string lines. Measure to the hubs
front & rear to get it set up.
Now measure from the string to the tyre, at the front, & rear of
each wheel. With one front wheel set parallel, the difference on
the other front wheel, front to rear, is your toe in or out. Adjust
as necessary.
At the rear there should be no difference on either side. It is
quickly obvious if the housing is bent, [wheels are not parellel],
or aiming off to one side. If the latter, look for wear in the
trailing arm bushes, or bent chassis.
Unless you are much better than me, it will take quite a while to
get the car central, & the strings parellel, the first time. After
a couple of times, you can check your toe in less than half an
hour, & this method is as accurate as the best gear available.
Have fun.
Hasbeen
