tester123

Hello!

Recently, there seems to be a leak at the flex-pipe in exhaust. Wondering what's the best way to address this issue? Can this section be replaced without buying entire new exhaust?

ETKA doesn't list any separate part number for this...

thanks!

arjun90

ECS Tuning apparently has Flex Pipe replacements with Audi Part #'s; however, this search was performed for an Audi A6 C5 3.0L, perhaps you might find the same for a 4.2L

georgeb944

There are several vendors selling weld in flex pipe sections on ebay. I have had good luck doing the welding in place on my 2.7T cars, using stainless MIG welding. If you take it to a muffler shop, the typical cost is about $300 per side. My cost was about $15 per side.

Measure the diameter of the pipe before ordering.

pr0xZen

Aftermarket section parts can be had that will bolt in - but not just the flexi bend, YMMV and can't say much in regards to quality - but there are some reasonably decent brands going around. Still probably going to be cheaper than ~$300/side in welding job. If you can, or know someone hand with the welder - then cutting and welding in a new flex section is going to be by very far the cheapest option.

If you end up looking at both bends fixed at $300/side, then you might as well have a look at prices for a complete system.

arjun90

A mechanic I once went to suggested that its always best to replace the entire exhaust system in an event of a Flex Pipe Replacement. I suspeced that to be nonsense, when the I noticed the remaining portion of the exhaust was in immaculate condition, haha.

blink

Someone around here has a part number for just the flex portion. You can buy it at the local parts store for under $10. Pull the pipe, weld in the replacement, and your on your way. Oh, well you have to reinstall the pipe first.

arjun90

I believe ECS Tuning would have this information as well. Does the Audi website give a part number specific to flex part?

Metronet

Are the 4.2 downpipes stainless steel?

I removed the downpipes (SS) and cut them at the main catalytic converter (steel) side and than sent them off for Tig welding using stainless rod.

I got the flex joints from eBay:
Audi Exhaust Pipe Flexible Repair All Years 50mm | eBay

I'm not familiar with the 4.2 pipes but the original flex pipes for 2.7T are made of interlock, bellows, and woven. The 50mm ones I got from eBay are made of woven, bellows, woven. You might also need new sleeves with double clamps if you plan to remove the downpipes.

For ones in Vancouver, BC area I highly recommend Steve Hudson who did an awesome job for me and very reasonable shop rates

(One thing to note here is if you just butt-weld the flex pipes like suggested in the ebay description it will not be as strong as original. Steve also fabricated a transition steel tube from 2" to 1.95 to go inside the stock pipes)

Steve Hudson
604 724-5722
Division 5 Fabricating

tester123

It seems like the flex-pipe is before the Cats. I replaced the rear drive-shaft flange seal and now remember how it is setup.

Take a look at this image and towards the very bottom you can notice the flex-pipe.
http://www.rs6.com/attachment.php?at...7&d=1321645510

The worst case scenario, it looks like the pipe(s) would have to disconnected right after exhaust manifold. The next pipe section is what extends the manifold through flex-pipe and cats.

This is a PIA job without a lift. Not necessarily a difficult one but I can see it could be time consuming as the entire exhaust (except the manifold) would have to be dropped. Removing the middle (bolt-on clamps) exhaust and rear is very simple.. but the rest is not going to be. Those pipe go up behind the engine to the manifold and there is little room..

any thoughts?

Here is a screen print:

tester123

I got an appointment with a midas shop tomorrow that also does custom exhaust work and will see what they say.

When you cut them and had them weld, how were you able to make sure that curve of the pipe was accurate? Or it doesn't matter?