My 74 must have been rear ended and repaired at some point in it's life. Right along the back edge of the car there are bumps in the floor pan to suggest this. I also have rust holes that look like swiss cheese just along the rear boot seam, the rest of the floor and the body around it is still pretty clean.

I bought a partial repair panel from seven enterprises. I was planning on drilling out the spot welds on the rear seam and welding it back together with the new panel. If any of you have done the same repair, I'd appreciate any advice or pointers you may have.

 

Sounds like you are already set on your plan and it is a good one. One down side is the heat from the welding is gonna screw any paint in the area and with where you are working I'll guess you r taking the fuel tank out.

Had you considered any other forms of repair? The POR15 folks sell a floor pan repair kit that I've used in similar situations with good results.
http://por15.com/prodinfo.asp?grp=FPTRK&dept=11

And for that matter you could clean it real good and fiberglass it as this area isn't external as I read your description.

 

I think that the original plan is a solid one. If you take your time and do it right it will add to the value of the mini. When it is all welded up and such you can seal the area so it will not rust again.

 

I pretty much need to repaint the car anyway cause it was red and then was painted over with black and not prepped well. Other areas need some minor body work but by far the boot is the worst of it. I guess one of my main concerns is actually getting the repair pan in place. The seam sticks out wider than the inside of the boot so I think I'm going to have a hard time getting the pan in place without bending it out of whack.

 

If you want to see a bunch of this type of repair, check out my Cardomain site for my XK-E, I replaced all the floors from the front bulkhead to the rear bumper! Drilling the spot welds then installing a new correct factory piece is definitely the right way to do this. Take your time and it will turn out fine. Don't just patch it, and don't fibeglass it..................
BTW, I had never done any body work before tackling my E-Type. If I can do it..........here's the link http://www.cardomain.com/ride/505677

 

i wouldn't rip out the whole rear boot pan.........cut out what is needed and add new piece(s) back in.......if this is my old car, the rest of the boot was fine.......

 

The repair piece I have only comes out a little past where the floor starts to go down into the spare tire area. You are right the pan is clean other than the back edge.

 

You will find there are 3 panels that come together to form the rear bumper lip. The bottom is the rear valance, the middle is the rear of the boot floor and the top is the rear body panel. You will need to drill out the spot welds on the rear bumper mounting lip and carefully remove the middle piece, which is the boot floor. You may find it easier to replace the rear valance. That way you could cut off the valance and grind the bottom away from the bumper lip, through the boot floor and just into the rear panel. If you find the rear panel is rusty, you can buy the piece that goes between the boot hinges and replace just that. Then you will have to carefully measure and then cut away the rear of the boot floor to match the repair panel, or cut the repair panel to match the existing floor, your choice. Then its a matter of welding it all back in. You need a mig or tig welder for this work. Of course, you will have removed the petrol tank by now, one way or another! The three panels of the rear lip were originally spot welded, but you can drill holes in the top panel and weld thru if you don’t have a spot welder. It may be easier to get the rear panel & boot floor just right and then install the valance. Just make sure everything fits properly before you start welding. If you are not a good welder now, you will be when you are done. Fortunately, most of this is hidden!

I recommend two books for you. Both cover this type of work on Minis. I think they are out of print, but I found one on eBay. The first is Practical Classics Mini Cooper Restoration and the other is MINI Guide to Purchase & Do it Yourself Restoration by Lindsay Porter. There is a newer book in print by the same author with a similar title, but I know nothing about it.

Good Luck! BTW, where are you located?

 

Bobbie, thanks for the advice. I never even thought to drill a hole and then use a mig to weld it. Thats pretty slick. The local vocational school has a night class where you can bring in you car and use their equipment 2 nights a week so I probably will take the class and use their spot welder.




I am from the Pittsburgh, PA area.

 

Follow Bobbie's advice. It is a good learning project. It'll give you confidence to tackle anything on the Mini. BTW, I may have an extra boot floor end repair section and the lower hinge rail for the boot lid in amongst the panels I have for my S. If interested, I'll check it out.

 

I may need the hinge rail. I did some more cleaning yesterday and found some holes in the rail filled in with body filler. I already have the floor pans.

I have welded in some patches before and they have turned out pretty decent but this is a much bigger project than what I have done before. I'm not in any hurry to get it back on the road so I'll just take my time and fix it right. Thanks everyone for your help.