It can be very difficult to find an alignment shop that will get an
older Mercedes aligned correctly. I have had MB dealer shops get my
car completely wrong.
By the way, to answer your question directly, it is most certainly an
alignment issue when the inside edges of your front tires wear
excessively. I have been driving a 1982 300 TDT for about 20 years
and until I found the alignment guy I have been using for the past 8
years I had a terrible time getting the car aligned correctly. I have
had several pairs of front tires ruined by bad alignment causing the
inside edges of the front tires to wear prematurely. I always keep an
eye on that because it can become a safety issue pretty fast if the
alignment is out.
Those "computer alignment" places seem not to have the correct
parameters for the older Mercedes in their memory banks.
The guy who aligns my car now does not use those swiveling circular
metal plates that the computer balance systems use. He has an old
fashioned grease pit. He pulls the car over the pit and has a long
steel caliper like a giant micrometer that he uses to accurately
measure the distance between the front rims at the front of the front
wheels and the rims at rear of the front wheels and then sets the toe-
in to the proper specification. I have not had a set of tires ruined
since I started taking the car to the guy. He is not at a chain store
type of shop, but at a locally owned place called T&T Wheel Alignment
and Tires in Ridgecrest, California. I have aligned cars myself using
a grease pit and just a tape measure and gotten them close enough, but
the steel caliper method is much more dependably accurate. I would
prefer a backyard alignment with a tape measure to one of those
computer alignment places. When I was farming we always used that
method to align the tractor.
You might think the camber being out is what is causing the inside of
the tires to wear, but it is most likely the toe-in. Camber is the
lean of the tire relative to vertical, so if the camber was out and
the wheels were leaning top inward the car would be riding on the
inside edges of the tires, causing them to wear abnormally. Camber
has not usually been a problem with my 300 TDT.
If your car pulls hard to one side the caster may be out. Caster is
the measure of whether or not one wheel is in front of the other.
It's the measure of how far forward or backward the wheels are
relative to the front of the vehicle and they should be at the same
point relative to that.
But, again, toe-in, if one wheel is more to one side than the other,
can also cause the pull and countering that pull is what wears out the
inside edges of your tires.