Way worse than it looked. - PeachParts Mercedes-Benz Forum

300SD81 · #1 07-21-2008, 06:17 PM

Battery tray rust is way worse than it looked when I first spotted it.. It looked like just a little surface rust when the battery and tray still in there, but after removal, I found a HOLE in the metal!

Where is the hole going!? (not the one where you see the ground, the one above it). Whats the best suggestion on how to fix this? My welding skills are nowhere near whats needed to cut and replace it...

turbobenz · #2 07-21-2008, 06:20 PM

I think it goes into the footwell if it get bad enough. Not sure what to do if your not willing to weld some sheet on there

Its not hard! Atlest take weld some sheet over it then seal it with polyurethane or something

Oracle12345 · #3 07-21-2008, 06:59 PM

JOIN THE CLUB

To properly fix that you will have to remove the dash and any of the parts that prevent access to it. the other side of that is jsut above the climate unit consisting of the evaportor, heater core ETC. You can make a patch piece then rivet it in WHich i would recommend because you can catch the car on fire or distort the metal in that area due to the heat.

GOOD LUCK

NoSparkNeeded · #4 07-21-2008, 07:29 PM

No I don't sell this stuff but I've used it for many years. I've restored a couple award winning cars, out in the street in front of my house no less,
and have used this stuff to seal rust inside of gas tanks, on floor boards
and many other things. The rougher the surface the better this stuff works. Just be sure to chip off all loose flakes. I sealed a Norton tank
many years ago, and the guy is still riding it. It will bridge some holes
if you duct tape one side for the first coat, then put a second on both sides. Is it as good as cutting out and welding? Depends. On rust that
consists of finish body repair, I've always cut out and welded, then used
"ALL-METAL" body filler. Some refer to it as "AlumaLead". Where a fine finish is not required, I've always used POR-15. The only downside is that
it really reacts to UV, so I always topcoat it with something. I used it on some guys boat trailer once. It got dipped in saltwater all the time. It lasted more than 5 years. Only because of chipping due to damage did rust start to come back. If a surface remains sealed from O2 it cannot rust.

Monomer · #5 07-21-2008, 07:51 PM

rivet in new sheet (or weld, if you have a welder handy - spot welding is fine)

rust proof with por15 or chassis saver.

coat in RV roof rubber sealer (any rv center will have it) weather proofs it, completely seals out water. Then comes the topcoat - I perfer gloss black.

Flounder · #6 07-21-2008, 08:12 PM

What do you guys have against fiberglass? That's an ideal place to use it. Are any of the cars on this board going to be judged at Pebble Beach? So slather on a couple of layers of 'glass and fabric/mat and be done with it.

When the car is going to the crusher many years from now the fiberglass repair will still look like the day you did it.

vstech · #7 07-21-2008, 08:22 PM

that severe rust spot needs some chemical treatment if you are not going to cut it out and repair it.
DO NOT PUT FIBERGLASS ON THIS!
at least get some chemical rust converter and seal both sides with something to properly condition rust.
ALSO I have read that JB Metal weld can do wonders to seal pop rivited patches!
give THAT a try before fiberglass.

300SD81 · #8 07-21-2008, 08:55 PM

The hole seems to lead to a hollow area, I can tap the bottom of it from the wheel well, what is that area for? It seems like some kind of hollow channel, but I can't tell where it goes.

Going to attack it with a dremel as soon as I can fix the dremel... ($5 cheapo off-brand..) We'll see where it goes from there. Seems like just surface rust around the edges, and if I can just tack weld some sheet metal (maybe cut from a junkyard car so its already shaped?), that'll be fine, just can't seem to run a good weld no matter what i do, especially since I can't see worth crap in my welding helmet...can't afford a good one

Cr from Texas · #9 07-21-2008, 09:56 PM

My 123 had a hole in a similar location and it took me three years to find it. Everytime it rained, I'd have water standing in the right rear passenger foot well. That's the low spot! The water was running from the hood hinge pocket (drain full of trash) to this hole, through the firewall, then under the front carpet (it never seemed wet). A heavy rain would leave 1/2 inch of water in the rear.

Once I found it, I cleaned the area, treated with rust converter, filled the hole with epoxy putty, JB weld over that, and rust preventing paint. Once the battery tray was back, no one could see it anyway. That was about 2002 - no problems with the repair yet. I put in a new batter this year and removed the tray for an inspection look - no signs of rust or failure.