It is time to tackle the front springs. First thing, get some proper tools. The correct way of changing front springs on a w123 (and many other MB models) is with the original (or copy of the original) spring compressor. I have a copy, it costs significantly less than the original Klann, but it is still very expensive. So unless you have a lot of cars, it may make more sense to rent this tool. Here you have it.
The tool consists of a rod that goes into the middle of the spring and two plates that is mounted in each end of the spring. Turn the nut in the rod, and this then compresses the spring so that you will be able to mount it.
There is one problem though. On a W123 you are supposed to exit the rod through a whole in the inner fender. Like this:
But if you try it, you will see that the whole is actually too small for the rod.
From what I have been able to find out, it is only the original Klann tool that actually fits. All the copy tools are a hair too big. So the best way to do it is to enlarge the hole with a tool like this:
After a couple of minutes, the tool suddenly fits:
Here is the underside:
Now we place the tool in the middle of the spring, and the two plates in each end of the spring. The tool has two different plate sizes, so choose the correct one that fits the spring 100%
Wrench away. Do not use air tools. After some wrenching, you will have compressed the spring like this:
Now you can mount it. If you are like me, you may find out that you were not able to compress the spring enough, then you just have to move the plates further to each end of the spring, like I had to do. This picture is my second attempt, now I was able to mount the spring.
Then put the wrench trough the hole in the inner fender, and decompress the spring.
Voila! You are done.