Anybody want to weld a flange back on a downpipe?

[Dean]

Turning onto Lakeside tonight for the SCCA meeting, All of a sudden had a massive exhaust leak on my A4. No loss of power, but up front and very loud.

Got home and the downpipe appears to have just fallen out of the flange on the turbo. About 1/4" of clean pipe is exposed and just hanging down a 1/2" below the flange. Luckily there are head shields all around the area, so no obvious damage.

I'll look closer tomorrow. I hope it will just pop back in so it can be tacked and then removed and welded up. It doesn't look like there we any external welds, so it was either a press fit or internally welded.

[sperry]

What's it made out of? How thick is the material? If it's mild steel I can give it a shot, but I've never welded anything super thin, though I figure the flange is pretty thick so it's probable not a problem.

Can you just mark it with a sharpie and remove it in two parts so you don't have to tack it while it's on the car? That's a lot better than driving the car w/ a broken exhaust.

[Dean]

What a PITA! I hate working on Audis. F'ing Germans don't think anyone will have to take anything apart in the car. Same idiot must have designed their exhaust bolt locations as the Subaru Mad Dad headers. Cat to downpipe has a 3 bolt flange and of course one is right behind where the pipe bend towards it instead of either side of it.

And I have no idea how I will get to the bottom turbo flange 17mm nut once the flange is attached to the cat again and in the car. Yes, the intelligent Germans decide to put the only cat in the engine compartment, not under the car.

Oh well, enough whining.

Pipe is not ultra thin. At least a couple millimeters thick. Flange is a big heavy thing. It was welded and then ground smooth from the inside. Very little weld penetration, or so even that it fatigued almost perfectly all the way around.

A nice weld on the outside would have easily taken the tension put on it.

I'll bring it to the meet if you are going to be there to look at and decide if you want to take a shot at it.

[Kevin M]

Cats get snugged up to engines now because it makes them start working a little faster. EPA thing.

[sperry]

I should be at the meet, though I may be a little late 'cause I have to go home and feed the dog before coming out.

If the flange is beefy and the pipe is thicker than plain sheetmetal my welder should be able to do it. I just shouldn't do stainless w/o buying a new spool and tri-mix gas.

[100_Percent_Juice]

Originally Posted by sperry

I should be at the meet, though I may be a little late 'cause I have to go home and feed the dog

I've heard of "buttering the muffin" and "slappin skins" but never "feeding the dog". You are a sick man Scott.

[Kevin M]

How did you miss "beefy" and "thicker?"