Found out my car has cancer. - PeachParts Mercedes-Benz Forum

DieselAddict · #1 06-21-2003, 03:50 PM

I've had this car for almost a year and felt quite proud of it because mechanically the car is near perfect with great engine compression, and the body, other than having a few dents has good paint, especially on the hood which I recently had repainted, and no rust, which I always attributed to the fact that it grew up in Texas and later here in Nevada. Well, that's no rust on the outside.

Last weekend I did a thorough wash, including the engine and behind the battery and afterward I noticed the passenger side floor mats were a little wet so I removed them and I was shocked to find lots of rust on the floor and about half inch of water in the rear. I'm still grieving a week later, though I feel a bit better after I dried the floor, peeled off the top non-metallic layer and sprayed the main metallic part with the anti-corrosive Super Lubricant and cleaned it a little. Fortunately, most of the floor is still good, but some places are quite rotten, especially around the rear left support of the front passenger seat and other places where water had pooled up.

My question is, about how much would it cost to patch up these spots, or is it better to replace the entire floor? The driver's side doesn't appear to have any rust. I'm also thinking to just buy another car with good, rust-free body and sell this one, but that may cost me a lot of money, since I already invested about $3K into this car. I could also find a car with good body and bad or no engine and do a transplant, but that's probably expensive too. Or just leave it and wait until the front passenger seat starts poking through the floor...

Possibly there's a hole in the firewall behind the battery or it was my windshield seal, but that's hard to tell because recently I applied some glue to a section of it and it doesn't leak now and I don't know if it ever did in the past. Bottom line is, check your floor even if you have a "rust-free southern car"!

TN-W124 Diesel · #2 06-21-2003, 06:53 PM

thats bad to hear, I would just keep it since you have money invested in it anyway..

psfred · #3 06-21-2003, 08:31 PM

Very common problem on the W123, probably has a corrosion hole behind the battery, allowing water from the cowl drain into the body.

You will need to fix this (from the inside, probably), then repair the floor with new sheetmetal.

By this time, you are going to be exceedingly lucky to find one in as good a shape as you have, let alone better! Repair and keep it going, like the rest of us.

Peter

#4 06-22-2003, 09:18 AM

will do a repair using a kind of "liquid metal" for under $400. Would be good to scout out other problem areas mentioned.

One of the really nice things about these cars is that, having been on the road for more than 20 years, a LOT of information on topics like rust has come up and been gathered, much on this site.

If the chassis isn't compromised, I'd say almost any rust repair on these cars can be justified, especially if they're strong runners and otherwise in good condition. Think W123s were the world's last "permanent car."

DieselAddict · #5 06-23-2003, 01:25 PM

Thanks guys for the replies. Yesterday I spent the time to find the source and cause of the leak. The source is to the left and somewhat behind the battery (looking from the front) where the water drain was plugged and water accumulated. Perhaps some spilled battery acid by previous owners accelerated the rusting, but it looks like plugged water drains were the main cause. Even half of the battery tray has been eaten away. The driver's side drains were plugged too and I cleaned them in time to prevent the formation of another hole.

I'm thinking to plug the leak hole with silicone to stop the leak. Would this work? I'll have to call around and get some quotes on repairing the floor. At this time I'm still contemplating just getting a different car and it will partly depend on how expensive it'll be to repair this rust. The passenger side also has some dents and parts of the car have bad paint, so I'm wondering if it's just better to start over with a car that has a really good body.

wolfgang · #6 06-23-2003, 01:43 PM

Buy a $350 MIG machine, go to the junkyard and get some steel (I use the roof of a car cut out with a torch or a Sawzall, nearly free) and fabricate the pieces you want and weld them in. No other repair is satisfactory. Fiberglass, rust compounds bondo wood etc is all garbage. It only exacerbates the problem. Not to many years ago welding was out of the realm of the home mechanic, not so anymore (look at junkyard wars). Girls can do it. For structural integrity and peace of mind no other solution is acceptable.

rwthomas1 · #7 06-23-2003, 06:19 PM

Yeah, what Wolfgang said! Lincoln WeldPak 100 flux-core wire feed arc welders can be had for $299 at Home Depot. They work great for light sheetmetal work. A true MIG welder will work a little better but will cost you about $450. Some salvaged sheetmetal the welder and misc. supplies should but you at @ $500. You can fix the damage yourself and you get to keep the welder too. RT

73MB280SEL · #8 06-23-2003, 06:39 PM

I agree with Wolfgang, RT, BUT: For true MIG welding (Metal Inert Gas), you'll need a gas bottle. You'll have to go to a welders supply shop and rent a bottle from them. The reason you rent the bottle is that they won't fill a bottle that is not theirs. The reason they won't do that is because they want to know it has been pressure tested.

I believe a MIG welder setup will also do flux core wire. For this, you need no gas as the wire has flux in it. It makes a sloppier weld, though.

Maybe you could temporarily patch it now to stop the water leak and then figure out what it will take to MIG weld. I recommend a book titled "Gas Metal Arc Welding Handbook" by W. Minnick. This is a short book but has alot of detail in it.

Sholin

rmmagow · #9 06-23-2003, 08:14 PM

Another place to check is where the hood hinges store themselves. The spring can be easily wiggled out and a bright flashlight will show you if you have a problem there. If it only just beginning to have a problem, clean it, dry it out and paint it throughly with Rust Encapsulator (eastwood) or por-15. It will hold up a long time. I fiberglass matted the section rotted out near the battery and it's holding up. As the others said, weld in the floor patches. Even if you have someone do it for you I wouldn't think it'd be a fortune. There are a lot of little welding shops around. I don't think there are many really rust-free old MB's around with 200K + miles on them. These old diesels just get used to death but never seem to die, just rust away.

73MB280SEL · #10 06-23-2003, 08:48 PM

I agree with RM, every MB is going to have a little rust somewhere. These cars just are prone to rust.

Sholin

Alec · #11 06-24-2003, 08:24 AM

I had some rust in the right rear floorboard in my wagon. After it was all cleaned up I had a hole about 8"x10". I ultimately cut all of the rusted metal out, used a grinder to get to the bare metal, painted it with rust inhibitor then cut a sheet of galvanized steel as a patch. I used about 18 small screws/nuts to fasten it in place then sealed it with silicone, paint and a final application of undercoat on the outside. Its difficult to even tell its there. All told it cost me about 20 bucks. The hardest part was contouring the metal to the floorboard but fortunately it is all straight lines.