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How do I unbolt the flex pipe (down pipe) from the cat?

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Old 05-08-2007, 11:08 AM
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Default How do I unbolt the flex pipe (down pipe) from the cat?

I'm switching out the entire exhaust... and for the life of me can't figure out how to get to those bolts.

Also, since mine are somewhat rusted-- what size are they?

TIA!

In case it matters...
B5 5MT 18.T A4
Old 05-08-2007, 11:25 AM
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Default i think the easiest way is to go from the bottom...

take off the axle heat shield and you should be able to get to the nuts pretty easily. It is still a pain though.
Old 05-08-2007, 11:31 AM
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I used a 3/8" U-joint and long 3/8" extension and it was pretty easy
Old 05-08-2007, 11:31 AM
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Default Spray the bolts with WD40 or PB blaster and let them soak for a couple

hours before attempting. I think they were 13mm
I used a universal joint between the socket and
3/8 extension and that work for me nicely.

Do you have Tip or Man? What exhaust are you
installing?
Old 05-08-2007, 11:43 AM
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thats what she said
Old 05-08-2007, 12:13 PM
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Default forget the sizing if they're rusty you need ot BATHE them in some sort of bolt penetrating oil first

then you can either remove your air box and heat-shield and cat and get to the bolts this way, or you can loosen some of them from up top the car and some from under it, jack the car up high enough to get under the flexpipe and use a long extension after the bolts have thoroughly melted, otherwise you'll do what i did and twist the head off one and be screwed now trying to remove the rest of the bolt. if this does happen many people can do it call around and bring them the part that's messed up, don't go with 2 bolts, as audi designed this part to have 3 in there to hold the exhaust on, i'd hate to see your custom exhaust fall off or something.
Old 05-08-2007, 12:29 PM
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from below... some of the cats have the "nut" end welded to them. You need to remove them from belo
Old 05-08-2007, 01:29 PM
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Default he should know it can be done from the top if u remove air box and disconnect turbo

just so you know. it took some reaching and hitting hand and forearm, if you get everything out the way you can do it i think i did it with the air box on btw. and no i didn't replace my k03 gasket.
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