Help fixing rust in rear of 1992 740

[chronicrhythm]

I have a 92 740 that is in very clean shape except for two spot in the back where the spare tire is. Not even sure what to call this area and can’t really see why it is rotting like it is. I’ve attached photos of it to hopefully get a clearer idea of it. One first picture is of the drivers side, second is passenger side, and 3rd is passenger side underneath. Anyone fix or encounter this before? Thanks. I try not to drive it in the winter anymore because of these spots.

 

[Pietercc]

I think @Jack can give you some good advice, since it is a 700 series

 

[okoye]

it's probably because the rear of the car floods from the drains. but it looks rusty enough that water might also be seeping in through the rust.

 

[Nagrom]

Hows yer weldin?

 

[chronicrhythm]

it's probably because the rear of the car floods from the drains. but it looks rusty enough that water might also be seeping in through the rust.

do you mean the drains in the buttcheeks?

 

[chronicrhythm]

Hows yer weldin?

Not great but I have the tools and my brother can help because he’s much better than me haha

 

[okoye]

do you mean the drains in the buttcheeks?

yep

 

[Jack]

I think @Jack can give you some good advice, since it is a 700 series

Crush it

 

[chronicrhythm]

Crush it

it might break the crusher! Maybe I’ll just sell it for $500

 

[dl242gt]

Have you looked under the battery? If that is rusty more than likely you need to fix the metal under the battery, too.

 

[chronicrhythm]

Have you looked under the battery? If that is rusty more than likely you need to fix the metal under the battery, too.

Yeah that is a little rusty there as well but not bad. I tried to remove the rust under the battery and paint it to keep it from getting worse but I think next winter I’ll do some body work to it. The car just hit 274k!

 

[Nagrom]

Knock all that rust out with a hammer and slather everything with por15.
It will just keep spreading otherwise

 

[dl242gt]

POR15 or Eastwood Rust Encapsulator. Both have worked great. I like the Eastwood stuff because the fumes aren't as bad and it's easier to clean up if you get messy.

 

[ortho stice]

I think this guy's video covers welding in patches in roughly the same areas?

 

[59volvo]

Use ospho then red oxide primer then fiberglas then paint

 

[Jack]

Use ospho then red oxide primer then fiberglas then paint

Eww fiberglass is just a temp patch that will make things worse in the long run