Muffler install on 325i

How hard is it to install a muffler on E30 325?
I understand I'll need a dremmel tool for the bolts, which are likely frozen beyond removal. What else? Do I need to do any bending? Should I
expect problems separating the mulffer piece from where it joins the cat? What about the install?
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SQ wrote:

If you are strong enough and the bolts rusty enough, you can save all that Dremel work by putting a wrench on the bolt and breaking the whole clamp off. For separating the rusty pipes you can cut a lengthwise slit in the pipe near the end and whack the opening with a hammer and chisel. That will break the rusty bond and the pipes will come apart. They use air chisels and torches down at the mufler shop, but you can get your job done with that toy if you have to.
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I gave up working on my own exhaust systems years ago. I found that the work was just too hard to do at home with the tools that I have, and the muffler shop fees turned out to be less than my time is worth. I had a complete system custom made -- bent and welded -- and installed for about $80, plus the muffler and CAT, and the work was done in less than an hour that would have taken me much longer at home.

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Please share this great find with us. Is it in the pacific northwest?

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No. It was a Mom & Pop shop in my town, just outside of San Diego County. The price I gave was just the labor, it does not include the cost of the muffler or the CAT.

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There are two flanges that mated the flared end of the two pipes exiting the cat to the two flared ends of the pips heading towards the muffler. These may well be seized/broken. If you can free them, the job is pretty simple really, your replacement OEM-style part comes complete with piping all the way from the muffler to the cat in once piece. All you need is perhaps a hanging kit. The thing you're tring to preserve is the flared pipe edges on the cat, the bolts and collars are replaceable.
If you can't free them or if you end up damaging the flares on the cat, you'll end up cutting them out, cutting the flange off the muffler pipes and the cat exit pipes. Then you'll fit an oversize sleeve and a pair of clamps to each pipe to mate them. Not very elegant but it will get the job done.
That's the only part that gives you trouble, the rest is attached via rubber hangers.
Installing the muffler isn't that tough, but I will warn you that if you straps are rusty, replace them because they will cause the face of the muffler to rust prematurely and fail well before the muffler should be failing. Ask me how I know. :-) If you're on a very small budget and you don't want to replace rusty but functional straps, try cutting a strip of alumnimum for repairing household heating ducts and wrapping it around the mulffler where the straps each go. But you might find the straps rot out on their own shortly afterwards if they are very rusty to start with and then you have a strip of rusty metal bouncing and sparking around under the car next to your left rear tire.
If you are reaching the point of despair tring to separate them at the cat, or if you need new exhaust header heatshields or the heatshield over your cat is rotted out, you can also drop the entire exhaust as a unit and work on it outside the car -- right from the headers if you want, those bolts are probably about the cleanest of them all, the ones at the collector/cat union will be about the worst. Warning, if you do this, it's a heavy peice that comes out! (and mind the O2 sensor) 2 people is best for this method. After fitting the new muffler together with your chosen mating method (that sounded odd) leave it loosely and fit/hang it back up properly before you tighten your new joint. Marking everything on the ground before you start cutting will help you fit it together approximately correctly for when you offer the entire unit back up to the car.
-Russ.
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SQ wrote:

My bolts at the cat/muffler connection were in Very, Very Bad Shape. I put the car on stands Friday evening and squirted the screws liberally with penetrating oil. Repeated the next morning. That afternoon they came out without hardly any fight...
Re-assembled with anti-seize and was glad I did when a year later I had to remove them again to replace the driveshaft!
Lemuel Johnson
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snipped-for-privacy@yahoo.com says...

Don't waste your time with a dremel tool. Last time I tried that it took more than a half hour to get one bolt grinded off. Get a 4.5 inch grinder with a good wheel on it. It should take less than 5 minutes per bolt. I also found that if you can remove the system intact from the car and then work on it out of the car, it is easier. ----------------- Alex
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says...

Advice seconded on all counts -- the advice about the repeated penetrating oil treatments also, for that matter -- if you get that lucky :-) -Russ.
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Alex Rodriguez wrote:

A sawzall will make short work of any exhaust system when you're trying to remove old rusted crap. I find it cuts quicker and cleaner than a grinder.
But I'm like the guy who has given up on DIY exhaust work. I even have access to a welder... but unless the system bolts together I just can't seem to line the pipes up so they're not banging or hanging...
Ray
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says...

You know I'm with you on that having tackled a few of these myself -- those guys at the muffler shop earn their money in my book...
-Russ.
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