drivfour

My flexpipe cracked leaking untreated exhaust fumes. removed dpf to gain more room. downpipe disconnected and free but cannot remove up nor below. Watched video(s) but they dont provide enough detail on exactly what parts must be removed. The body of the cat seems to get wedged between the firewall and some emission equipment that looks to be very difficult to remove. others have indicated they did not remove this body. not able to drop below either.
any detailed experience /suggestions helpful. 2011 q7 tdi

-Wes-

I have not removed mine, but it is a terrible PITA to access the bolts on the DPF to downpipe connection. Sounds like you already tackled that, though.

What is in the way to bring the cat/downpipe through from under? I don't recall now....

drjonez

It is possible to take it out the top if you get the orientation perfect and you bend space/time. Easiest way is loosen the back two subframe bolts and drop it out the bottom.

Blackfunk

My flex pipe broke a few years ago and I initially thought it was a simple job but after giving it a shot I realized I was out of my depth. I ended up taking it to a muffler shop and watching the amount of work that was involved I felt like the might've undercharged me ~$180. Took them about 1.5hrs to get everything removed and reinstalled. They also needed to cut away some pieces as they were too rusted to be removed.

drivfour

in the end the two important steps were to relocate the two metal pipes running left/right somewhat below the cat and dropping the subframe an inch or so. I carefully removed one bolt at a time and put back in 5 rotations. the other thing I did was to cut off the mounting tab on the inboard side of the cat- it kept getting hung up on the side of the transmission. It was fairly easy to get back in with the inlet rotated towards the driver, up and then rotate back. I had the dpf loosened so the studs had more room for engagement. i ended up welding a flex pip onto the old flanges and cat- took forever to grind them down to get a 5/34 length back- very important to trial fit and mark the rotation so the flanges are clocked correctly.