Don't look a gift coupe in the mouth (?)
 

This summer, an old friend of mine gifted me a '78 300CD. It had been his daughter's high school car, and she didn't want it anymore. After sitting outside unused for more then two years, it needed new brake calipers, a fuel system debugging, and updated glow plugs. It drives beautifully, easily out-handling my '85 TD, even though I had just spent a small fortune on the wagon's SLS. The coupe is fun to throw it around on back roads, at nice legal speeds that would have been very dull in my '97 528i (RIP). The interior is in lovely condition, except for a badly cracked dash (covered with a cap). The exterior looks great from 25 feet or so, but of course the tin worm has been active...

My question is about the rust on the rockers and the bottom of the doors. The rust does not yet show on the door skins, only on the bottom. The metal lip that held the weather stripping is completely gone on both sides. What would you do? A proper repair with new doors and rockers would probably cost more then the car is worth. Maybe a treatment with POR-15 and some fiberglass patches would buy me some time. The car is a toy. I keep it garaged and don't drive in the rain. Any suggestions?

Don

More pictures at:

http://homepage.mac.com/donindigo2/PhotoAlbum111.html

New rockers are $100 a piece, the UPS man just delivered them to me. New doors are available too. If it was me I would fix it. Whether you fix it or not depends on how you feel about the car.

Or pass it along to me, I'm not far from you in VA :) Free pickup too. In all honesty that looks like some serious rust. I'd hate to see a coupe rust into nothing. I've always liked them. You should at least price two new doors. Those won't be easy to fix (lots of labor). The rockers look like they should be replaced. With rust like that I'd also check the fenders. I've never seen that kind of damage without other areas being in similar shape.

-Tad

Thanks for the replies.

There doesn't seem to be any other rust to the degree of the pictures above. The front fenders and hood were replaced after the previous owner rear-ended somebody a few years ago. The rear clip and trunk lid were replaced when she was rear-ended in turn a few weeks later (hence the improper badging on the trunk). As for the rear fenders, I'll post a couple shots of the worst of the rust one them. Doesn't seem that bad. There is also some problems around the antenna opening, and on the drivers side of the sunroof has some surface rust. Probably a blocked drain. You can see some of the rust on the rear control arms in the pictures above, but that seems to be surface, and not structural.

ADSIT has doors for 595 apiece, but I haven't seen any others available. Replacing the rockers myself is a job beyond my skill.

As for other issues, I have service records back into the '80s. The ACC servo-from-hell was replaced five years ago, for instance.

I like the car a lot. With the windows down and the sunroof open on a nice day, it feels almost like a convertible. I'm not looking for a show car, just a fair weather toy, and a backup for my 300TD. I had been looking for something smaller, an E30 BMW, or a 70's Alfa before this fell into my lap.

Don
Bel Air, MD

Hi Don- nice car! I too look to jump into rust repair sometime soon since my coupe isnt getting any better letting the rust eat it away. Be careful, I replaced my drivers door with one from ebay for $175 that only had "minor surface rust" It turned out to have the whole lower part of the door where the seal sits completly rusted through. My trunk lid came from potomac german across town here for $80, not a spot of rust on it, they might be able to help you out with doors and if not them, there is a pre 1980 280CE at a yard in mt airy, although I'm not sure of its rust condition.

Thanks for the reply.

My family priorities don't allow a ton of money to be spent on this car at this time. I'm thinking of pulling off the door panels and treating the rust with POR-14 inside and out and attempt to patch the doors along the lines of what is discussed at **************.com. The doors will get priority since they look fine on the outside--no visible rust, and maybe they can be preserved for several more years. I've been told that the rockers are not structural, only caps. Maybe they could be POR'ed and patched as well, until they can be replaced. Maybe next summer...

How much more is it going to deteriorate, if I keep it garaged and dry?

Don
Bel Air, MD

Here are some pictures
 

Here are some pictures to help you inspect the car, start on page #9 and go forward.
There should be more rust hiding.

Who has the most rust and still drives
http://www.peachparts.com/shopforum/bodywork-repair-paint-tools-tips-tricks/86054-who-has-most-rust-still-drives.html

Thanks for the link.

I spent a good deal of time under my coupe this summer, replacing the exhaust system. I saw lots of surface rust on some to the rear suspension components, but certainly nothing like this recent thread:

http://www.peachparts.com/shopforum/bodywork-repair-paint-tools-tips-tricks/135604-w126-horrifying-rust-discovery-help-opinions-wanted.html

Pulling out the carpets have revealed nothing there either. The floorboards are sound. I've looked for rot in places indicated on the rust thread, and have found nothing yet. Rust is funny stuff. How could it have such severe local damage, but not all over the car? From sitting unmoved in the weather for so long?

Its too bad our diesel's automatic rust prevention mechanism works only in the front of the car, not elsewhere. ;)

Don
Bel Air, MD

Ah yes, the self lubricating chassis! what an ingenious idea those crazy germans came up with. Just make the car leak oil after 10 years and prevent rust!

If its a big enough leak, it will lube all the way back to your bumper!