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Fri Sep 02, 2005
This is going to be a fairly long post, as it encompasses events spanning quite a few days. It started late last week while I was at work. Pete (Claire's father) stopped by my cubicle and said that Claire had called from college and said there was something wrong with the Jetta. Something about tons of noise and something about the transmission and/or shift linkage. "Great", I think to myself, "Possible transmission problem - just lovely." Several hours later I spoke with Claire on the phone and, based on her description of things, I was pretty certain that the exhaust had broken. I had patched a nasty exhaust leak several weeks earlier, so I was expecting that it had finally broken into two pieces at that spot. At any rate, I wasn't looking at a transmission problem - whew! I ditched work a little early and drove to the parking lot where the Jetta had been sitting so that I could take a look at it and make sure it would still be okay to drive back home. By getting under the car and wiggling the exhaust, I could see a break near the back of the pipe that goes from the catalytic converter to the resonator. I was a little surprised, because the break was not where I had previously patched it. Nothing was hanging down, though, so the car was still perfectly safe to drive home - it was just very loud.

So we got the car home without incident, and I found myself faced with a decision: Patch it or buy a new cat-back system. I was sick of patching, so I decided to call around a few places to see what was available for new systems. My favorite place for stock exhaust and brake parts, Double Discount, turned out to be a little pricey and they would have to order the parts (which would take several days). I then called Atlantic Imported Auto and was pleasantly surprised to find that they not only had a cat-back system in stock, but it was a reasonable price as well. I like the guys at Atlantic a lot - they're friendly and they really know their stuff. I was happy to give them my business. Their shop is literally right down the road from us, so I blasted down there to pick up the parts. Upon returning, I pulled the Jetta into the barn and put it on jack stands.

It was around this time that I noticed something bad:
Photo of Jetta exhaust work
What you see here is not actually a complete break - there was still a tiny bit of the pipe left intact at the top. This is directly behind the catalytic converter and, as it turned out, it was actually part of the pipe exiting the catalytic converter that was rotted away. I wasn't too worried about it at this point, since we have so much spare pipe hanging around. My plan was to clamp an extension onto the catalytic converter to replace the part that had rotted.

Here are the pieces making up the new cat-back system. The mid-pipe is Bosal, and the 2 muffler sections are Ansa.
Photo of Jetta exhaust work

The old system was pretty easy to remove, as it was nearly falling off on it's own. I made one cut in the over-axle pipe and here's what resulted (note my previous tin-can patch ahead of the resonator):
Photo of Jetta exhaust work

My next job was to come up with a section of pipe that would slide over the damaged end of the catalytic converter and slide inside the new mid-pipe. It was during this process that I came to realize how messed up the old exhaust system really was. The catalytic converter was obviously not original, and the outlet pipe it used was not only thinner guage metal, but smaller in diameter than a factory cat. The outlet pipe on the cat briefly flared up to the correct size at the very end, to mate correctly with a factory mid-pipe. The aftermarket mid-pipe that had been on the car, however, briefly flared up to the correct size at the catalytic converter end and then ran the whole length at a smaller diameter than the factory mid-pipe. So what was on the car was a very long section of pipe 1/4" smaller in diameter than factory. That sucks.

Anyway, I eventually ended up with everything mated together and hung in place. After a lot of tedious adjusting to make sure nothing was going to hit the chassis or the rear axle, I tightened everything up, as seen here:
Photo of Jetta exhaust work Photo of Jetta exhaust work

I started the car and there was still a pretty bad exhaust leak coming from the joint between the mid-pipe and the catalytic converter. The way the remaining pipe on the catalytic converter was shaped, there was really no good way for it to seal against the mid-pipe (even with the sleeve I fashioned). Time for a new catalytic converter, which Atlantic ordered for me. I had it two business days later.

While removing the old catalytic converter, I remembered why I hate working on exhausts. Everything's rusted to the point where the heads of the nuts and bolts are rounded off, but they're still far too strong to just bang apart. After lots of PB Blaster, a couple of Craftsman Bolt-outs, and a little bit of grinding with an air powered cutoff wheel, I got the old cat out. Here you can see both the old and the new cats side by side:
Photo of Jetta exhaust work

Here is another reason the catalytic converter needed to be replaced (although I didn't know beforehand):
Photo of Jetta exhaust work Photo of Jetta exhaust work
Here you can see the start of some clogging. Not good.

The new cat was pretty easy to install, compared to removal of the old one. Make sure to use good stainless steel hardware when installing a new catalytic converter or any other exhaust part that is made of stainless steel. In this case, the mid-pipe is also stainless steel. Not only will it save you having to replace the hardware 3 years down the road, but it will be that much easier to remove the hardware the next time work needs to be done. So here is the new catalytic converter in place, in front of the new cat-back system:
Photo of Jetta exhaust work Photo of Jetta exhaust work

And everybody lived happily ever after. :) That whole thing was a real pain, I'm glad it's over.

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