Do I dare replace my alternator?

[arnoneh]

My alternator is not generating juice even after replacing the voltage regulator. I replaced alternators in old 70s US cars when I was a kid but I noticed some threads here about people having problems replacing their alternators.

My car is an '85 300D turbo wagon. Seems like it should be straightforward: remove wires , loosten bolts, remove belts, remove alternator. Reverse. The only thing that might cause me problems is getting the belt tension right.

What complication am I missing in my simpleminded approach?
How do I best get the belt tension right w/o the special measuring tool?

thanks -Harv