Crimped Nuts

[rickert at c4.com]

After a three and a half months spent traveling around Europe, I have returned to something more or less approximating reality here in the Seattle. Having neither driven nor worked on a car since the end of March, I came back severely in need of some automotive contact. Fortunately owning an Audi provides plenty of opportunities to work on ones car.

I started with a small but annoying problem with the exhaust system on my 87 4kq. I had the entire system replaced last summer, the guy did a nice job with the exception that the bolts that hold the flange between cat to the downpipe together loosen up with time and it gets noisy. Everything is straight and looks like it should seal without a problem. I thought that fixing this would simply require some of those special crimped nuts used for exhaust systems.

The first problem is that I can’t find any of the special nuts; I went to two different auto parts stores and a muffler shop without success. Are these things necessary? I should think that with the proper torque, normal nuts should be just fine, but I don’t know much about exhaust systems.

The second problem is even with a new metal “gasket” and very tight fasteners (with normal rather than crimped nuts) there is still a noticeable amount of exhaust noise around the middle of the car. It reduces as the car warms up, but remains louder than it should be. I know that I should have dealt with this while I was living near the shop that did the work, but I am now 300 miles away.

What do I need to do to fix this problem? Should I use some sort of sealant on the “gasket” and prepare the mating surfaces in some way?  I can’t understand why this thing is so difficult to get to seal up properly.

I would like to publicly thank Mihnea Cotet for his hospitality when I visited Belgium in early May.  The weather was lousy but the people were friendly.  It was good to meet a dedicated Audi enthusiast. The waffles, beer and chocolate weren’t bad either.

Luke


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