My rust free 300D ain't. The rubber grommet for the antenna had long been kaput on this car . I am developing a hole at the rear bottom of the car as a result of this long neglected leak. Should I bite the bullet and have this professionally repaired or can I cut out the bad section, POR-15 the area and use a fiberglass based repair method. I don't know how to weld nor do I have a welding machine.
This is the only area that seems to be having any problems at all. I want to nip it before it creeps into the visible part of the car. Right now, you can only see it if you look for it. The other side is solid with no evidence of any upcoming issues. The only other section needing attention is the front, under the bumper. Years of road debris have sort of sand-blasted this area and a good sanding, rust primer and paint would save it. I intend to keep this car forever. I'm 61, forever won't be too long :-)

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1985 300D 197K - Semi-Daily Driver Diesel
1998 Volvo V70 AWD 226K - Daily Driver 2
1998 Volvo S70 140K - Wife's DD
2003 GMC Sonoma ZR2 Option - Rusty Truck
THE BABY 1958 220S Sedan 66K All original, never restored and never will be.

As for functionality, the POR and fiberglass will work just fine. If you want the car to be "perfect" then cut, weld, body work, and paint is required. It will drive the same either way. I prefer the price of functionality on a driver myself, but its an individual choice.

Good luck!

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You can't always get what you want, but if you try sometime you just might find you get what you need.

Functionality is my goal with judicious preservation as a byproduct. Perfection is generally out of the question, I need to use this car. It's pretty nice as is and to keep it this way will make me happy. I am a perfectionist doing most mechanical things but body work perfection would not be worth the effort for this particular car. at this time anyway.
Thanks

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1985 300D 197K - Semi-Daily Driver Diesel
1998 Volvo V70 AWD 226K - Daily Driver 2
1998 Volvo S70 140K - Wife's DD
2003 GMC Sonoma ZR2 Option - Rusty Truck
THE BABY 1958 220S Sedan 66K All original, never restored and never will be.

After wire brush and POR-15 type system =>

If I were you I'd have a look at epoxy fillers instead of fibre glass. There's a product called nu metal that isn't really metal but as damn hard as it - well it seems like it! This sort of thing is fine to use on parts that don't need any strength.

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

I was about to suggest something similar using JB Weld. If the hole is small enough then a metal plate epoxied to the inside of the well (Perhaps Aluminum) with JB weld protruding thru the hole, like bondo, and sanded down and painted should work well I'd think.

- Peter.

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2021 Chevrolet Spark
Formerly...
2000 GMC Sonoma
1981 240D 4spd stick. 347000 miles. Deceased Feb 14 2021
2002 Kia Rio. Worst crap on four wheels
1981 240D 4spd stick. 389000 miles.
1984 123 200
1979 116 280S
1972 Cadillac Sedan DeVille
1971 108 280S

Sheet metal, pop rivets, and seam filler
Then paint
Really easy and very strong
no welding required
Just drilling some small holes
Required is a simple pop rivet gun (cheap and some rivets (also cheap)
Better and less nasty than POR 15 and fiberglass
As well as much less expensive

Exactly I have been doing this for years except I use thin aluminum flashing from a hardware store. Won't rust, easy to work with, can be cut with a scissor and strong but not structurally strong, then again neither is sheet metal.