So on my 99 2.8 A6 the flex pipe has rusted out. I got under the car and yeah its pretty bad. My question is i found new flex bellows here http://www.ecstuning.com/stage/edpd/...ory=Universall but how do I got about replacing them? The downpipe, flex, precats all one piece or can i just swap the Flex in there some how?

 

The flex pipes are usually welded inplace by a muffler shop that has the right tools. If the other parts of the pipe are bad you should replace the whole assembly.

 

The flex pipe isn't to bad to replace with a straight pipe or replace. You might just need some new clamps and a good tech . You need to watch out because all of the welding is done by the tranny / subframe of the car. This makes it a tricky job because you need to get the top but obviously not weld your exhaust to your car ;P. Or you could also get clamps that connect piping (forgot the name right now of those clamps... will update sorry )... you might need 4 of them but would work. I would go somewhere where they don't rape you for lifting it and taking the exhaust off. I did this with my tech about 2 weeks ago took about 2-3 hours to remove and reweld the piping.

 

Replace the flex with a straight pipe????
Ya gotta be kidding! Right?

They use a flex pipe so that every time the motor moves it dosent move the whole exhaust system and put it in a bind.

 

i'd want to see how much flexing this motor does against the mounts. for decades, exhausts were 1 solid, unflexing piece from the heads to the tips. flex was introduced with front wheel drive. i can't imagine it helps with audible drivetrain noise, but i don't think it would cause a binding scenario.