Exhaust replacement - Cat/resonator flange rotted out

[JayPea44]

Hello.

I recently picked up a fairly nice 07 xc70. It pretty good shape but due to the Michigan winters it's in dire need of a new exhaust. I have found many stock options which is great, but then comes my problem.

Where the downpipes ends after the cat, the flange which mates to the remaining exhaust is shot. The mating surface itself seems salvageable but the big issue is the bolt holes themselves have rusted out so much they no longer exist. So attaching the down pipe to a new resonator pipe and back would be essentially impossible.

I feel I have 2 options (maybe 3?):

1. Just buy a new down pipe + cat assembly and replace. (Don't really want to do this as taking the down pipe out seems like an annoying job to do on my driveway and I really don't want to fight the 02 sensors.)

2. Fabricate a bracket to go around the down pipe mating flange to replicate the old holes and hope it seals.

Maybe 3. Grind the flange back to the edge of the pipe on the down pipe and resonator and get a universal band clamp to go over the join. I don't think this will work as I don't think I'll get flush enough to the pipe for a good fit on the clamp.

Wondering if anyone else has run in to this problem and solved it in a different way or has any advice.

Cheers.

[vtl]

Use dremel to drill the slots in the flange, knock the studs out, use stainless steel bolts/nuts/shims. I had this setup for quite a bit.

[JayPea44]

My problem is the holes aren't holes anymore. The bolts aren't stuck they're gone, so the holes are now effectively half holes. So a bolt won't stayed captive in the slot as its tightened. The holes have broken across the lines as on the attachment.

I was going to use stainless steel bolts for sure.

[cn90]

Visit the local junk yard to see if you can get good downpipe.

[cn90]

Right now, eBay has a P2 S60 muffler for $150, genuine Volvo brand. I bought it this summer and can verify that it is genuine Volvo muffler.
Look under eBay seller "KTRXinc"...

[vtl]

Visit the local junk yard to see if you can get good downpipe.

They were all gone during CAT steal pandemic.

[cn90]

I saw good downpipe in my local jy.

[vtl]

My problem is the holes aren't holes anymore. The bolts aren't stuck they're gone, so the holes are now effectively half holes. So a bolt won't stayed captive in the slot as its tightened. The holes have broken across the lines as on the attachment.

I was going to use stainless steel bolts for sure.

Get a cheap flux core MIG welder, a spool of SS wire, mate the flanges with SS bolts as best as you can, preheat the DP flange with MAPP torch, weld the bolts to the flange. Plasma and welder do magic for old cars maintenance, I use my all the time.

[JayPea44]

Right now, eBay has a P2 S60 muffler for $150, genuine Volvo brand. I bought it this summer and can verify that it is genuine Volvo muffler.
Look under eBay seller "KTRXinc"...

I can get the muffler and resonator pipec at-back on parts geek for like 250, all in, or eBay for like 300. No problem there. My problem is getting it attached to the cat.

Think I'll try and fabricate a bracket and if that doesn't work I'll find a replacement down pipe.

[JayPea44]

My problem is the holes aren't holes anymore. The bolts aren't stuck they're gone, so the holes are now effectively half holes. So a bolt won't stayed captive in the slot as its tightened. The holes have broken across the lines as on the attachment.

I was going to use stainless steel bolts for sure.

Get a cheap flux core MIG welder, a spool of SS wire, mate the flanges with SS bolts as best as you can, preheat the DP flange with MAPP torch, weld the bolts to the flange. Plasma and welder do magic for old cars maintenance, I use my all the time.

This seems more expensive than just getting a new down pipe. My FIL is a welder, maybe I can ask him.