I was cleaning up the bottom side of my 2003 discovery, I had old por15 paint and it’s starting to peel after a few years so I’m removing it and
applying Eastwood rust encapsulated platinum and as I was cleaning the frame I punched through alittle on the back passenger side and now there is a large hole and a smaller hole 6 inches away from that one and it’s the only spot on the whole frame even the other side rear is perfect what do I do here? Can I just weld a piece of metal here and call it a day?

 

That's what I would do, if you can a U shaped piece wrapping would be best

 

Nah, that's rusted from the inside out, and there's more damage than you can see.
I have seen several this way.
When I bought my 04, it had one small, ugly rust spot on the outside rear of the passenger side frame(U.S model) near the vin#.
After a couple years, it became a huge hole, a the boxed part of the frame basically fell apart.
Meanwhile, the perfect looking other side has since became terrible looking, and it basically appeared overnight.
You'll need a frame back half, unless you can cut out ALL the rot and fab and weld plates back in, and by plates, I mean top, bottom, left, and right side too.
Road salt and moisture get trapped in the boxed section of the frame, and then it's too late.
Not to mention it's low quality British steel, and that they don't salt their roadways.
I am considering a frame swap, or a cheap donor truck with a good frame and body.
I don't think spending nearly $2k on a frame back half is worth it either. As it would kill any resale value.

 

Frame seems fine past the hook section which is right where the rear quarter replacement ends so I think I might invest in that. There is alittle rust around the top of the spring tower section but nothing that can be sanded off and coated. It’s around 500$ and I can weld it all myself. Anyone have experience? I dont really want to do the whole half chassis

 

The whole back half looks easier, because it bolts on, then gets welded. So it should be easier to get square.
I've been back and forth, because my Dad can weld mine.
But, as said, is it worth the time and money?
I wouldn't buy a D2 with a back half frame repair, not only because I don't know if it's straight, will wear out tires, etc.
And even if I had no plans to sell it, that repair is going to kill it's value.
So I'll pass, and go the frame or truck swap.

 

Issue I have is the truck only has 60k miles and for some reason the whole front of the frame is perfect I’d do a whole swap if the front was also not great. It’s just past the rear springs on one side it’s iffy

 

Mine is the same.
Frame is good all the way to the rear axle.
Paint, body, interior, and drivetrain are all good(other than sagging rear springs and to finish rebuilding my engine).
It's an 04 with 112k miles.
Sad, as it's pretty worthless as is, and I've spent a small fortune in new parts.
Once I get it running again(soon, just finding time to finish), I'm going to post it here with lots of pictures, and see what the consensus is on it's value...a black on black 04 in great shape with a rebuild engine, clean title, clean carfax that needs nothing...except a frame, lol.
Good luck with yours.

 

Maybe we need sacrificial anodes on our frames?



Such as:

 

I would not be concerned about a frame back half behind the springs, there are not significant structural pieces back there and alignment be be close enough as it does not affect suspension. If your welder is good and then you dress and coat the welds, it will be almost as good as new.

 

I don't disageee with that.
But, as a guy who's bought a dozen of these, what does that frame back half repair say to you if you were looking to buy?
You've seen my D2, and said if you were selling it(running of course), that it would be $7k, maybe more.
Only now, the back half of my frame is toast.
It should be worth what?
Now I get a new back half. What's it worth now?
I know it's only worth what someone's willing to pay, and different areas/markets all matter.
But, hypothetically, ballpark, what do think on value?
I agree that a good repair would be ok, but I can't see it being worth as much as a D2 with a good frame, since they're still out there.
And that most people will shy away from the repair for those reasons, and would pay less.
I would pay much less for a repaired truck, or most likely not buy it at all, wouldn't you?