Catalytic converters on my 07 Expy started throwing a code a while back. I verified the sensors were good, so the cats must be bad. Called a couple muffler shops and was blown away at the cost to replace and was told they're too close to the floor to weld in universals so they need new pipes, etc.

A month or so ago, developed an exhaust leak. Broken exhaust stud on the drivers side. So I Pulled it apart the other day, drilled and extracted the stud, and have a new manifold and studs on there right now. When I ordered the manifold, I also got universal magnaflow cats to weld in there while it was apart. I have a good wire welder, though I'm not the best welder.

I called a couple of local muffler shops to see if they could clamp it down, cut apart, and weld it all together since it's all apart already. They say they don't have any kind of a jig to hold it and can't do that.

So, I'm probably going to cut the old cats off and clean it all up, mount all the pieces with the new cats in place, weld the bottom, then pull it back apart and weld the top. Problem is that I'm not a great welder. I'd rather have somebody who know what they're doing weld it. Do I have any better options? May have a friend come over who is a welder but he works a lot so I didn't want to bother him. Anybody have any better ideas or know where I can get them welded?

TLDR version: anybody know how to get a muffler shop to weld cats into exhaust pipes while off the car?

I did it on my nissan when the cats failed. It's not hard at all. It just takes patience. TIG is better but a small wire feed on a low setting won't burn through and you can tack it in place then take it out and weld it up completely and fit it back in. You may have to leave one clamped Union in to give you some play.

Cats get hot, but not that hot if properly sized with good flow. I also used some generic high flow magnas of a size that would fit where I needed them.

Pravtice on some scrap or extra bits of exhaust pipe or adapter until you can draw a nice bead along the seam. A tiny crescent drag motion or push pull motion might work well.

Magnaflow has good replacements that are reasonably priced. I have a wholesale access to them if you need but amazon comes within a few bucks.

No need to weld if you have a bit of a straight section. Use some quality lap joint band clamps.

Inspection failed me for band clamps in a non emissions county. Mainly because there are small leaks at the joints. I started going to dedicated inspection places without a pit and they never even look though.

I guess I'm going to cut them apart, bolt on, and weld today. I'll post the results, no pics of the welds tho. I'm not a terrible welder, just don't do it much anymore and I'm pretty critical of myself. Worst thing that can happen is I end up buying the full replacements.

Can't clamp, not very straight and the main reason to fix it now is that I'm problem buying the lady of the house a newer Expy and selling this one. Don't want it to fail anybody's inspection.

Sounds like its too late, but I think you need a better exhaust shop. The good exhaust fab shops will use mirrors and flex nozzles, or even pull the shield and crank up the gas flow and other creative tricks to not drop the pipe when replacing.

http://www.richs-performance-mufflers.com

Years ago had this guy replace the cats on a car of mine and it was quite the lesson in welding out of position

Almost started working on it yesterday and ended up spending the day looking at newer Expys. Ended up with a great deal on a 2016 EL Limited in navy blue. My first boooooost. I had my heart set on a 2014 KR with 4x4, I was hoping to supercharge it, but the wife loves this one.

Might have time to get back on the exhaust system on Friday again. Working and running around a lot before then.

Also, forgot: the cats I used were flowmaster.