Originally Posted by Diesel911

The Steering Box has a plug at the bottom that can be remove and a pointed bolt inserted that screws into where the plug goes and the point goes into a hole inside and centers the Steering box and with it the Arm on the steering box.

In the pic is the one I made and the plug (copper crush washer is missing).

When you remove the plug not a lot of fliud will come out but as it sits it eventually drips/leaks out. The same if you use the pointed blot. Put a pan under it.

However, the steering box being locked in place dose not guarentee that the wheels wre actually pointed straight forward as example due to wear or the adjustments on the Tie Rods.

If you look under the front of the car you will see that there is Holes drilled in various parts of the Chassis. Some of those holes go down the centerline of the car and Mercedes has an elaborate setup that bolts into those holes for measuering.
So if you determine the centerline of the car you can detemine if the wheels are straight or not and from there the actual toe in.