Feeling bummed about my 300TD... major floor pan rust - Page 2 - PeachParts Mercedes-Benz Forum

aaronkobi · #16 04-08-2008, 11:06 AM

When picking around at the front passenger floorpan, I noticed that it seems like the pan is 2 layer... one on top, about an inch gap, then another layer of steel below. Sound right? If so, it's going to be really tough to get in between those layers to treat all the rust. I also discovered some previous fiberglass repair. I guess I'll be yanking that out too so I can make sure everything is done right. This is going to be one hell of a job...

Knightrider966 · #17 04-08-2008, 11:14 AM

While I don't have any rust on either of my Benz's, I have removed exptensive rust and repaired it before. If you really like the car, and it sure sounds like you do, this will all be worth it and just remember to keep that in mind since it can seem overwhelming at times!

I can say easily that these cars have been the best I ever owned and it is totally worth it to me to spend the money it needs to keep them on the road! $5000 for an engine overhaul is a fair price to pay for a classic Benz that has a durability and dependability behind it, which is STILL a lot cheaper than a payment book!

Since I don't have to do this yet, I'm watching this thread with interest! If you could find time to post pics of your progress, I'd like to see them.

aaronkobi · #18 04-08-2008, 07:59 PM

I just returned from Home Depot and Advance Auto... I am now armed with 2 sheets of steel, JB Weld, steel rivets, fiberglass resin and mat, and a LOT of POR15 from a previous purchase. I'll return what I don't need, but, nothing worse than having to go to the store once you get started on a project... total cost for all these materials, about $300, hopefully that will be close to the total cost of the repair work.

Once I get the interior and sound deadener out, I'll post photos to get some opinions on a plan of attack. I'm feeling a lot better than I was last night!

Since the carpet has been soaked for probably 10+ years, there's a lot of mold (I'm very allergic to mold), so, after the repairs are complete, I'm going to replace all the carpeting with a set from German Auto Tops. $750 for everything, front and back. I figure I should be able to complete this repair and have new carpet for 1/2 as much as if I had taken it to a shop to have the work done. Doesn't seem as bad when I look at it that way.

I'm thinking of lining the floorboards with rubberized truck bed liner instead of using sound deadener. I don't see any way of ever getting this thing completely leak proof, so, might as well have something that can't absorb water. Has anybody else done this?

Flounder · #19 04-08-2008, 08:21 PM

I think fiberglass is way underrated by most car guys. I repaired all my floor rust with a combination of riveted aluminum pieces and 2-3 layers of fiberglass mat over the top. You can't beat fiberglass for conforming to tricky compound shapes also, which you do find in the floor/sills of the MB. Much, much quicker than custom-forming metal.

If you laminate up 2 or 3 layers of mat, it will laugh at a hit from a sledgehammer once cured. I sloppily let a bunch of it cure on my garage floor a few months ago and I had to use my disc grinder to get it off.

Hatterasguy · #20 04-08-2008, 08:29 PM

Ahh the wonder surprises these old cars give us!

You guys got me so paranoid with all these floor rust threads that I went out and pulled the carpet up on the SDL and went underneath it. I can't find anything, the undercoating once I wipe the dirt off looks like new, no cracks, hit it with a hammer and it seems perfectly solid. The ashfault crap inside looks perfect, and I even broke away a spot above a rib to see whats underneath, but no surprises just clean new looking primer. So I don't know what else I can do other than fix any leaks as soon as they show up and keep it out of the salt.

aaronkobi · #21 04-08-2008, 09:21 PM

Quote:

Originally Posted by Hatterasguy

You guys got me so paranoid with all these floor rust threads that I went out and pulled the carpet up on the SDL and went underneath it. I can't find anything, the undercoating once I wipe the dirt off looks like new, no cracks, hit it with a hammer and it seems perfectly solid.

Man, you're lucky... that's why I bought a car in Florida (it had spent its entire life in Fort Lauderdale). Was hoping to avoid the northeast rust issues. Oh well, live and learn.

lutzTD · #22 04-08-2008, 09:29 PM

Quote:

Originally Posted by Flounder

I think fiberglass is way underrated by most car guys. I repaired all my floor rust with a combination of riveted aluminum pieces and 2-3 layers of fiberglass mat over the top. You can't beat fiberglass for conforming to tricky compound shapes also, which you do find in the floor/sills of the MB. Much, much quicker than custom-forming metal.

If you laminate up 2 or 3 layers of mat, it will laugh at a hit from a sledgehammer once cured. I sloppily let a bunch of it cure on my garage floor a few months ago and I had to use my disc grinder to get it off.

fiberglass floor repairs I have seen absorb moisture and trap it between the floor steel and the glass causing future damage everywhere it is used. I dont know if there is a way to seal the fiberglass, but maybe someone here will have a method. Ive seen a lot of small holes become huge ones under the glass repair.

Chad300tdt · #23 04-08-2008, 09:36 PM

Quote:

Originally Posted by lutzTD

fiberglass floor repairs I have seen absorb moisture and trap it between the floor steel and the glass causing future damage everywhere it is used. I dont know if there is a way to seal the fiberglass, but maybe someone here will have a method. Ive seen a lot of small holes become huge ones under the glass repair.

The POR-15 fibermat floorpan kit is better than standard fiberglass and resin repairs. The steps in the kit are essential to the repair lasting. There is a marine clean (cleaner/degreaser) used first, then metal prep which neutralizes the rust and dries to a zinc oxide coating, then rust preventative paint to seal everything. If the rust preventative paint isn't coating everything perfectly, then what you mention would happen. Another benefit to POR-15 stuff is it all is moisture cured. The POR-15 putty will even cure under water.

aaronkobi · #24 04-09-2008, 11:39 AM

Quote:

Originally Posted by Chad300tdt

The POR-15 fibermat floorpan kit is better than standard fiberglass and resin repairs.

You know... that actually makes a lot of sense Chad. Even if I were to coat the entire floorpan area in fiberglass, moisture would still get in underneath and continue to rust the metal. However, the POR on both sides of the metal completely seals it.

Ok, so the current plan of attack is sheet steel patches, steel pop rivets and JB weld, the POR paste to seal the gaps between the new and old steel, POR covering the entire thing. I want to do repairs that will last another 5 years (that's about how long I plan on keeping this car... hopefully we'll have more diesel options in the states by then!)

aaronkobi · #25 04-10-2008, 12:48 AM

Quote:

Originally Posted by lutzTD

fiberglass floor repairs I have seen absorb moisture and trap it between the floor steel and the glass causing future damage everywhere it is used. I dont know if there is a way to seal the fiberglass, but maybe someone here will have a method. Ive seen a lot of small holes become huge ones under the glass repair.

Confirmed. Was poking around in the spare tire wheel well and found that the PO had patched a rust spot from the inside with fiberglass patch. I pushed on the outside, and I heard the dreaded crunch of rust just under the paint. As I chipped away at the fiberglass patch, indeed there was moisture and water trapped underneath the fiberglass. I started grinding from the outside and by the time I got to clean metal, I ended up with a hole about 8 inches long and 3 inches high.

It really sucks when you realize that you've purchased a rust bucket

pawoSD · #26 04-10-2008, 01:14 AM

Its not so bad.....my dad repaired a significant amount of rust on his 300SD....and so far it has held up well.

asnowsquall · #27 04-10-2008, 07:19 AM

Quote:

Originally Posted by aaronkobi

It really sucks when you realize that you've purchased a rust bucket

It does, but on a positive note you will learn where the bad areas are of the car and know what to look for in the next one.

Chad300tdt · #28 04-10-2008, 08:27 AM

Quote:

Originally Posted by aaronkobi

Confirmed. Was poking around in the spare tire wheel well and found that the PO had patched a rust spot from the inside with fiberglass patch. I pushed on the outside, and I heard the dreaded crunch of rust just under the paint. As I chipped away at the fiberglass patch, indeed there was moisture and water trapped underneath the fiberglass. I started grinding from the outside and by the time I got to clean metal, I ended up with a hole about 8 inches long and 3 inches high.

It really sucks when you realize that you've purchased a rust bucket

Aaron, here's a link of some rust I had to deal with. Maybe it will make you feel better.

Remove the window seals to repair the rust

I still love my wagon and think it's worth the effort to fix.

Quote:

Originally Posted by asnowsquall

It does, but on a positive note you will learn where the bad areas are of the car and know what to look for in the next one.

I totally agree with that

The way the undercoating is on these cars, the rust really remains hidden. I've done rust repair on quite a few vehicles and never saw the amount of hidden damage as I found on my MB.

Every job I've done has been a learning experience. All the knowledge I've gained with my car has made my wife confident enough to let me get her a classic MB diesel too. I hope to find a 1980 300SD or a 1985 300D.

aaronkobi · #29 04-10-2008, 08:54 AM

Quote:

Originally Posted by asnowsquall

It does, but on a positive note you will learn where the bad areas are of the car and know what to look for in the next one.

Did... you say.... next one?

I kid, I kid!

cewyattjr · #30 04-17-2008, 05:59 AM

Bummer. It it in the frame it seems? I'm curious what some of our more experienced folks on the forum will suggest. Sorry to hear/see about this and I really feel for you, it is a huge disappointment!

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