Question on best approach to dealing with this rust

[tdskip]

Good morning - hoping to get some advice on the best way to deal with this rear shelf rust behind the back seats.

Driver side is solid, passenger side not so much. Here are pictures of the areas.






Would you recommend "just" fabricating replacement sections? OR, think it would better to buy a replacement shaped piece such as below and cut to fit?

[tharbert]

Typically, what you see is the tip of the iceberg. You should post some good shots of the rockers and longitudinal area (around the torsion tube.) That said, I would clean that up with a grinder, find the spot welds in and around the corrosion and drill those out. Then trim out the bad and fab replacement bits. I think you'd be very hard pressed to cut up that non-oem shaped piece to fit.

[Bob Kontak]

Originally Posted by tharbert

You should post some good shots of the rockers and longitudinal area (around the torsion tube.)

This makes sense to me. From the pic below this area has the load carrying task.

[Jcslocum]

It will take a bit more investigation, but it looks to me (and I'm quickly becoming a rust expert as I restore an old Mini) that the rust is from water in the seat pan as the pitting is on the inside. Scraping and inspection the opposite side should confirm. If it is just localized ruse from water leaks to the interior, I would cut it out piece by piece and make repairs that way. Make sure they are BUTT joints, no overlaps and cut back to full thickness metal. No trying to work with the rusty edges, as they just disintegrate when touched with the welder. If you have overlapped area to fix, get a spot weld cutter, carefully remove the bad metal, use weld thru primer on the flanges before welding then properly seam seal.

Good luck!!

[tdskip]

Hi Jon - thanks for the note.

The pitting is indeed from the interior towards the back of the car, looks like water got in from a bad seal, ran down the shelf and then soaked into the padding and rust settled in.

I think I am going to need to, as suggested, buy a replacement panel and butt weld (agree this is key). I'll have a lot of the panel left over but seems like the best way to get the contours right.