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.
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.
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
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.
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!
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.
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
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...
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