W126 HORRIFYING rust discovery! Help/Opinions wanted... - PeachParts Mercedes-Benz Forum

pawoSD · #1 10-28-2005, 04:13 PM

So when inspecting my car for winter a week ago I went over the undercoat everywhere to make sure it was OK/no bubbling....I found about 5 places where it seemed rust may be underneath, and I peeled off the undercoat to find HORROR in 3 of the 5 locations, two of them were surface rust and have been treated. The others are a bit more scary. I am working at grinding and cleaning off these areas, but what I want to know is, after looking at these pics, do you think I should go ahead and have the two major holes welded? Or just grind the rust off, treat them super well with rust preventer/converter, and then seal them up with undercoat material....? My dad's friend can weld these area's shut tomorrow once I have finished prepping the surrounding metal, but I would like to get views from here on the forum about what would be the best solutions to this.

By the way, the real dark black looking shiny stuff on a lot of it is the rust treatment stuff, its pretty amazing.

Pictures are below:

You can see in the below picture that the frame was hit on something at some point, causing it to be smashed in/bent a little, it definitely happened long before I got the car, no idea how it happened.

The below pictures detail the massive rust hole I discovered under the undercoat behind the passenger rear sway bar mount. I treated the whole area VERY heavily with rust treatment stuff as you can see, and I don't think it can rust anymore even if I left it like this, I intend to add a huge coating of rubberized undercoat as well, to protect it even more. Should I have this area welded or is it not worth it. It seems that the metal that rusted away is fairly thin to begin with. The side metal (far thicker and stronger) is all in tact and OK.

Ideas and help on this situation would be VERY appreciated.......

300DPETE · #2 10-28-2005, 04:20 PM

Go to **************.com and type in "introductory rust repair" in their search box.

They write convincingly about the use of Miracle Paint with fibeglass cloth.

I've been lucky so far to only have to deal with surface rust in the engine bay, but I still ordered this guide just in case...

Pete.

Pete Burton · #3 10-28-2005, 04:22 PM

I have rust on the front worse than that. I've cut most of it out and should be welding in some new metal soon. It's underneath so it needs to be strong, not pretty. Chances are your dad's buddy will do those spots pretty cheap if you cut the rust out and clear the undercoating back an inch or 2. Shouldn't be more than an afternoon's work to fix that.

whunter · #4 10-28-2005, 04:26 PM

No fiberglass repair is possible in those areas, they are all STRUCTURAL support.
Grinding, cutting and welding is the only safe answer.
Been there done that on mine.
Mig or TIG welding is what I suggest.

Who has the most rust and still drives
Who has the most rust and still drives

pawoSD · #5 10-28-2005, 04:30 PM

So I sould just continue my undercoat removal and grinding and have it welded then? Thats exactly what he said, 2" around the sides so he can weld it good.

What about that rear area? It looks to be a pain to get in there and weld or grind at it. I may leave that one as it is for a while, there's no rusty metal there anymore, everything you see was metal thats still strong, I broke off and cleaned all the rust on the rear area, then SUPER treated it, the converter stuff is like cement, and the insides of the beam back there I sprayed in treatment aerosol and such to make sure no other places can rust, the original coating is also present inside the beam. If I just kept that part sealed/painted real good would it be ok? The front is the biggest concern....I want to get it sealed up well, so welding seems to be the way to go. It will be strong indeed if he welds it, he is going to use steel bracket pieces about 2x the thickness of the original metal....

I guess I'll go back out and continue grinding for a while......

pawoSD · #6 10-28-2005, 04:31 PM

Quote:

Originally Posted by whunter

No fiberglass repair is possible in those areas, they are all STRUCTURAL support.
Grinding, cutting and welding is the only safe answer.
Been there done that on mine.
Mig or TIG welding is what I suggest.

How much would you charge to work on/repair those areas?

If we could schedule a time I'd bring it to you to work on......if your able to/want to that is.

300DPETE · #7 10-28-2005, 04:38 PM

Quote:

Originally Posted by whunter

No fiberglass repair is possible in those areas, they are all STRUCTURAL support.
Grinding, cutting and welding is the only safe answer.
Been there done that on mine.
Mig or TIG welding is what I suggest.

Who has the most rust and still drives
Who has the most rust and still drives

The way ************** describes it, it's not a fiberglass repair in the traditional sense. They say that the Miracle Paint and the cloth form a bond that is so resistant to rust that it will outlast the metal.

However, I am not an expert in any way, so I will defer to your knowledge on the matter.

Pete.

Pete Burton · #8 10-28-2005, 04:42 PM

check the vertical area behind (inboard) from the rear jacking points too.

mbzkid · #9 10-28-2005, 04:49 PM

Welding the frame rail is no big deal, but it needs to be done. No doubt about it. The sway bar mount should be reinforced, and/or fixed. You don't want it to break off.

Be sure he doesn't weld near the fuel tank, or anything he shouldn't be. Don't let things get too hot under the floor boards when welding on the frame either. It shouldn't hurt the interior, but its good to be careful.

whunter · #10 10-28-2005, 05:01 PM

Quote:

Originally Posted by pawoSD

How much would you charge to work on/repair those areas?

If we could schedule a time I'd bring it to you to work on......if your able to/want to that is.

I will not discuss price on the forum.
Time is the killer for your idea, at least four to six days.
Grinding, cutting, metal forming, tacking into place, welding I will do.
Rust treatment I would leave to you.
The job is more difficult with rust treatment application, naked metal is better.
Rust treatment is flammable and highly TOXIC at welding temperature.
Ask Adam how his nerves survived watching me welding on his baby, and seeing it catch fire in small patches due to rust coat burning out of cracks.

Check with your local community college vocational tech center, the auto body and welding class may be willing to take on your car as a project for materials cost, I doubt they get to play with many Mercedes Benz.

kerry · #11 10-28-2005, 07:14 PM

You will not win the battle. Move Southwest.

blueranger · #12 10-28-2005, 07:58 PM

I will now share with you all my secret to no rust..

i guarantee this method.....it has always worked for me...

i never have rust becasue i always have oil and transmission fluid
leaks... that i never fix.... so the under side of my car is always coated
in a nice goop of oil.....

guaranteed....

PagodaLover · #13 10-28-2005, 08:18 PM

Is that car a MI native?

Hatterasguy · #14 10-28-2005, 10:20 PM

Pic 3 looks like someone stuck a jack their at some point. Since the jack points on my SD are pretty rusty my dad decided to put the jack on the frame rail. Now with a block of wood to spread the weight this is fine I have done it many times on the SDL when I want a jack stand under the rubber pad. But on the SD it crushed right up into the body!

That thing is a little rusty but I really don't care.

I'd have all of the holes welded up as best as possible. But I wouldn't undercoat the repairs. Undercoating sucks just paint it real good and leave it. That way you can keep and eye on them, just in case they fester again.

whunter · #15 10-28-2005, 10:22 PM

My concern is that all pictures are passenger side.
I need to see the same areas of the driver side.
A half repair of structural rust it not safe.
Driver side could be hiding almost as much rust under the rubber coat.