Rust Repair, Need Advice

[M3This]

Hi Guys,

 

Ordering some parts from restoration-design for some rust repair on my car and wasn't quite sure what to order (excuse the ignorance as Im new at this):

 

Passanger Rear Fender:

 

 

As you can see the rust is right at the seam line between the outer fender and inner wheel well. Im going to be putting Alpina style flares on the car which is going to require cutting the outer fender anyway, but 1) wan't sure that you cut the outer fenders that low and 2) If I should just order both pieces, or just the inner fender for the repair. 

 

 

[Mike G]

I’d pull the rear subframe and start trying to poke holes around the rear suspension mount on the body. You might be beyond ordering patch panels and into hand making parts judging by that rust. Or at least add rocker panels to your order. 

[zinz]

Totally agree with Mike. That’s a structural portion of the car, you will want to insure it is very sound. Pull the rear seats and look down in those corners where the subframe hanger bolts through. Grind all that area down to bare metal to know where the rust stops. 
 

It can be fixed, but like Mike says, you may have to fabricate some pieces. No problem... I’ve seen worse

 

Ed

[tech71]

Yeah really common trouble spot, on my car it was the opposite side. In my case, someone had stuffed a piece of closed cell foam into that area from the inside and slathered body sealant over the outside?

Hokey but it did provide a seal against moisture for many years.

Mine was fairly localized and I was able to clean up and treat effectively.

Yours unfortunately, is more extensive. 

Still have not welded on the patch, I'll get to it next time cars up in the air and yes,,, I will clean off the primer prior to welding.

Edited August 31, 2021 by tech71

[Tdh]

I'm with Mike, Zinz and Tech71.  I saved your photo and blew it up as big as possible.  There's an awful lot of loose rust in that hole.  I'm betting, like them that there are some issues down low.  At this point, you have nothing to lose by opening up the end of that rocker and looking inside.  knock all that loose crap out of there (shop vac) and start poking. 

 

In addition, I'd investigate upwards.  you have some loose and compromised coating in the wheel well above your obvious rust.  I'd want to know what was under all that before I started metal work below.  You can remove some quickly for a cursory exam with just a chisel or a screw driver for starters before bringing out the big guns (wire wheel, etc.).  

 

Good luck with it.  Don't know your level of comfort with this type of stuff, but a bunch of us on here have been doing this kind of repair work for a long time.  There's plenty of help here.  

[Mike Self]

17 hours ago, M3This said:

Passenger Rear Fender:

 

I'm piling on with the previous posters, having had more than a little experience with rusty 2002s...

 

If you look carefully at your picture, there are vertical cracks in the sealer going straight up from the existing hole. That's the factory undercoating that's cracked because the underlying welded seam has rusted and is pulling apart.  Take a linoleum knife and scrape away all that factory sealer/schutz on each side of and several inches above the visible crack to determine the extent of the rust; You may be able to get away with some additional seam welding where it's just surface rust (no holes) but down towards the bottom you need new metal, most likely hand-fabricated.  Once in and schutzed, it won't be very noticeable, but it's gotta be strong, because that's the area (as has been pointed out) where the subframe attaches to the body shell:  see the round, rubber cylinder immediately inboard and below your rust hole?  That's the subframe mount.  

 

Your rust there isn't bad, but just make sure you get it all and put in a sturdy repair so that the car's body and subframe keep flying in formation.

 

Keep us posted on your progress

 

mike

 

PS.  Sherwin-Williams makes some very good industrial anti-rust paint--for use on bridges, sea-going ships etc that really does a good job on coating both rusty and clean metal...

[M3This]

Hi guys thanks so much for all the advice. Much appreciated!  
 

Since posting that I pulled the rear subframe and all the interior is out. I have had a chance to start scraping yet as I’m currently just in the tear down process to get the frame/unibody ready to send off to OR for dipping. Still have to remove the gas tank, fuel lines and hard brake lines then is on to removing as much of the under coat that I can and sound dampening. Once I do I’ll post up some more photos before it heads to get dipped.