On these MB's, the whole lower part of the oustide door is covered by plastic.

There are clips at the bottom of the driver's door that hold the plastic to the metal door panel, but the clip at the rear is broken.

Another more serious problem is two small areas (about the size of a penny) of rust.
Right above the plastic, rust is growing.
It still looks white, but I know rust is inside the white coat, because the paint surface is bloated.

I thought of repairing it my self with POR-15 or RustBullet, but I have no experience in removing this plastic door trim.

Furthermore, at the top of this plastic, there is rubber strip. If the painted surface is not flat, water will leak. But I am not good at making the area flat, where I partially applied rust inhibitor and MB touch up stick.
I can use sandpaper to make it flat. However, factory clear coat (and white coat) will be sanded too, around the spot where I applied rust inhibitor.

Any advice?

Hi,

I've got the same issue. On both front doors there are spots at the edge of the plastic with rust starting.

I havent fixed mine yet but I can tell you what I am planning on doing.

Remove the plastic panel. This can be done by removing the two screws visible when you open the door, then you need to undo the snaps on the lower edge of the door (I think there are 5 from memory). These are supposed to be a pull straight out snap - one part stays on the plastic one part stays on the metal. I was worried about the strength of the plastic trim. If you lie down an look at the lower edge of the door from below you will see the clips. You can unclip them individually from below (which is what I did). once the lower clips are free the panel slides about 1 inch rearward and then comes off.

With the plastic off you can get at the rust.

My plan is scrape off rust and wire bursh and sand. Then paint with POR-15 (I ordered their starter kit in silver on Friday). To insure the surface is flat I plan to fill it after painting with POR's straightline body filler. Then topcoat with white to match the car (I believe my paint code is 147). The person I talked to at POR said I didn't need their primer, so I didn't get it.

I believe there are local places that will get color matched paints into spray cans for you. I'll be checking one in the next few days. Or you can order from Tower Paint which gets mentioned on these lists frequently.

Paul

I see only one screw at the rear bottom end. Where can I find the other screw?

__________________
1992 300D 2.5 turbo diesel. 319 k miles.
124.128 chassis, 602.962 engine, 722.418 tranny.

On my car there were two screws at the back edge of the door. One twards to top of the plastic trim and the other at the bottom. Both were visible with the door open, viewed from the inside surface.

The edge of the plastic trim that seats agains the sheetmetal has a strip of label like materail that seats against the metal. I would assume that is replaceable (I'm going to check today).

I have completed everything but the topcoat and reassembly. I plan on topcoating tonight. I did a test fit of the plastic after the APOR and filler. It fits up great.

Good luck.
Paul