Did the job on the 88 560SL just a couple of months ago.
Jack the car up and place it on jackstands. You only have to place the front on jacks. Remove the wheels it makes working on the suspension area easier. I raise the lower control orm with the jack I used to raise the car. The top nut of the shock requires 2 wrenches or the tool Mercedes has. I made one out of some square stock
Heres the post.
Making the Mercedes shock absorber tool
You don't have to weld the T handle on it. I had the welder so I did it anyway. You can just buy the 2 pieces and use them.
If you don't buy the home made tools. I found that I took one wrench and ground the open end section so that it was thinner that a standard wrench. That was so it can fit on the lower nut while you loosen the upper nut. A standard wrench is to thick and you can't get both wrenches on the nuts due to the lower wrench blocking the upper nut.
As David said, You have to remove the radiator expansion tank to get access to the front right shock top.
the bolts on the 88 SL at the bottom of the shock are star head bolts. You may or may not have these on your year SL. Sears carries a star box wrench in metric. Harbor Freight does too.
To remove the lower bolts. Its a tight fit for the wrench. I remember using both box wrenches and sockets for the job.
Remove the shock and you will reuse the plastic splash shield that is on the currently installed shock. There is also a foam bushing that is about 7-8 inches and goes on the upper shaft. You will figure out how it goes as you take it apart. Keep track of what comes off and in what order. If your foam bushing is powder, as mine was, Mercedes sells them.
I used the hydraulic jack to raise the lower control arm to assist in installing the shock. Its to short to have the lower shock installed and the top extend through the upper hole. so I bolted the lower end to the lower control arm and raised it with the floor jack to push the shock through the hole completely so you may bolt it in.
To remove the shock you may have to pull down on the top of the shock to make it short enough to completely remove it. I just pulled on the top of the shock with slow and steady pressure, It will slowly collapse, and then you can remove it.
Below is a pict of the wrench I had to grind to get it to work the upper shock nuts.
Go to the link I have posted, there is a diagram of the top washers, nuts, rubber bushings. This will help you reassemble the tops section in the right order.
Dave