Rust bubble W123 300D
 

Hi,

on my 83 300D, in my rear passenger side door, I have been getting a rust bubble. It is on the front edge of the door, 3/4 of the way down, where the metal goees in a bit (there is a little ridge).
It was there since I bought it, and after last summer, the paint got a bit iffy. There was a small pinholeon the paint, and every time d press in the area of the bubble, Id hear a crunchy sound. I eventually went over the hole with some touchup paint (letting the solvent get in there to help evaporate out the water). the paint wouldnt cloise up the hole, so I used crazy glue instad. The hole was quite small, more of just a sliver, but I managed to inject a bit of crazy glue in there and then use it to seal over the top, overwhich I painted with the touchup paint.

Now the actual door edge-side of the bubble is raising from the rest of the metal, and so I can see long pant cracks on the edge. The rust bubble has been contained for some time now, and hasnt gotten crunchy to the touch as it used to be, but I have noticed a bit of growth lately.

Is my door panel doomed? What is the best bet for preventing this from going further? Will I have to cut out and reconstruct the area? How difficult is this job goingto be? Can a good looking blended spray job be obtained by a DIY without professional spray tools?

Any help is most apprecated.

JMH

I Believe you can fix this very easy. If you have a haynes manual for your car it has a whole section on repairs and and touch ups of the body. you will need bond sand paper and sanding block, a puddy knife to apply bondo, backing if the hole is throught the door. the big thing is to take your time. do it over a weekend.


ps I do have a biege door if you want it ,that is in good condition. a nice salvage yard door will cost about 150 plus. tristarpete.comwould have one. I wouldnt sell mine for that much

Getting a very nice job will be difficult without a professional grade spray gun -- spray cans are almost never equiped with adequate nozzles, and the mix of propellant and paint causes serious orangepeel problems in amatuer hands (witness the hood on the 280 if you could see it -- looks like sandpaper).

You will need to remove the paint and all the rust down to bare metal to properly repair the spot, including in the seam between the door panels if it got that far. Scrape all the loose paint (the blister) off and as much of the rust as possible. You can use coarse sandpaper, but don't get too carried away. If you have an actual hole in the metal, you will need to add some fiberglass behind it, inside the door or weld in some clean sheetmetal, paint won't fix a hole.

If you feel you need body filler to smooth it out, you MUST grind all the way down to clean metal, as Bondo and related stuff really only sticks properly to freshly preped metal. Don't wait overnight, sand it clean and wipe with laquer thinner, the immediately apply the bondo. Allow to harden, the sand smooth. Make sure to use very fine paper that removes all scratches or they will show in the finished job.

Prime, wet or slick sand, then apply several coats of finish. You will need to mask the rest of the car off with masking tape and newspaper to keep overspray off.

You must cover any exposed bondo on the back of the panel with paint. Perferable not to have any showing, of course, but it is porous and will absorb water if not painted, and in a couple years, rust will appear under the bondo and force it off.

If you choose not to use Bondo or other filler, use an etch or conversion primer first, then without sanding, prime, sand, and paint. Make sure you don't sand down into the conversion primer, you will probably get rust recurring.

Peter

Thanks very much for the info guys, I really appreciate it very much.

JMH