Car is a 1977 280e --

Driver side door doesn't connect any more on its own. Door just bounces off the frame.

From what I can tell, there's a part of door that engages the striker in the frame that used to be spring-loaded and would move back when the handle was engaged. It seems to be flopping loose.

Ideas? Am I to just get a whole new door handle and replace altogether?

--Not a mechanic

The first and simplest thing to do would be to spray the latch in the door with WD-40, let it sit, and then spray it with a good spray lube. There is no need to remove the door latch, at least not at first, in order to reach the parts that may be sticking. Just work on cleaning the parts of the latch that are exposed and this will often clear up the problem

The problem could be the striker plate on the body of the auto. These wear and sometimes move as the car ages. You door latch is also wearing, so you are trying to adjust out the wear of both the latch and the striker plate.

The large Phillips heads that hold the striker plate will need to be knocked loose with a hand held impact wrench. These are inexpensive tools that can be set to clockwise or counterclockwise motion and come with four interchangeable heads. Pick out the large Phillips, set to counterclockwise, and strike the end with a hammer. The screws will come loose.

Before loosing the plate, (do not remove it) mark the current placement on the car's body. You will need a reference point after it is loose. And only back off the screws enough to move the plate by tapping it gently with a hammer. If it becomes too loose it will move a great deal and you will need to move it back to the original position before it can be adjusted.

Try moving the striker plate back about 2 mm, tighten it down, and test the latch function. This will quite likely require several attempts.

If the door latch problem continues you will need to remove and replace the latch assembly inside the door as it is not retracting enough to allow the latch to connect with the striker. Removing the latch is like many repairs on a Mercedes: Time consuming but not difficult. Once the latch is out it will need to be cleaned and lubed. After testing for correct function it would be replaced and the striker plate adjustment describe above would be almost 100% required to mesh up with the new placement of the latch.

The amount of acceptable difference between the two is around 1 or 2 mm. There is no way to check this except by constant adjustment.

Much obliged. I'll set to it and see how it goes. Thanks very much