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Fun with Exhaust Systems, or "So That's What That Noise

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Old 03-12-2005, 04:48 PM
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Default Fun with Exhaust Systems, or "So That'* What That Noise

For a long time now, the Bonneville'* been a little louder than it'* supposed to -- okay, it _did_ sound kind of cool that way, so I hadn't bothered to do anything about it, although there were some weird times with that, like if I was driving in the rain, it would suddenly get _way_ louder as road splash opened up an obvious leak somewhere underneath, but it would quiet down again after it had dried out, so life just went on as usual, for about as long as I've been writing this never-ending sentence.

But finally last week as I was racing for the morning train, I gunned it around a corner and suddenly things got MUCH LOUDER, PLUS THERE WAS THIS CLANKING-- sorry-- there was this clanking noise which definitely did not add to the sporty image.

So after limping home again, I had a look-see underneath, and found a clean break in the exhaust pipe just forward of the rear wheels, where the front half pipe connects to the back half. Looks like road splash built up around the front edges of the pipe clamp, and after six years it finally rotted the pipe all the way through. The back half had fallen to the pavement, but I'd made it home again without snagging it on anything that would have ripped it off.

Some quality time with the Bonneville files turned up the old Merlin Mufflers receipt: the muffler is guaranteed for life, but new pipes are going to run me $200.

Right... let'* try a home repair first.

So... if I can get the old clamp off, and somehow get the broken stub of inner pipe out of the back half, I should be able to use a 2½" connector piece to get the two pipes back together. Figure I'll get the old stuff off first before spending any money on this, since the worst work will probably come first.

Pull out the Bernz-O-Matic and start heating the rusty old clamp all over. Get a good fit with a deep socket on the first of the two 9/16" nuts, give a hard twist on it, and... it neatly shears right off. Should have tried that _before_ wasting all that propane on it. Oh, well. A few whacks with a hammer and the old clamp'* off.

Pause to run to Lee Automotive for a couple of new 2½" clamps and a connector pipe: the front half is 2½" inside diameter; the back half is 2½" _outside_ diameter, so it'll reattach two pipes that are too short to telescope together. Neat. Total expense after member discount is about four bucks; have to put it on the Visa card after discovering only three bucks in wallet. Good thing payday is next Tuesday.

Get back home and inspect about 5" of broken stub from the front pipe that'* telescoped into the rear pipe, behind the point where it broke. Discover that this broken stub was actually compressed undersize for ease of assembly in the muffler shop, and there'* no way the connector pipe will fit into it. Opening of rear pipe was originally slightly oversize, so wide end of connector won't fit over that, either. Broken stub is going to have to come out.

Decide to hacksaw off 3" of the rear pipe. This will leave about an inch of stub inside, with about 2" of the oversize pipe remaining that will fit the connector pipe. Find best hacksaw and start sawing.

This is slow going: metal is thick and rear pipe keeps bouncing around. Finally have bright idea of clamping the end of the pipe to the trolley jack (which isn't doing anything else at the moment, since right rear wheel is up on ramp). Hefty C-clamp holds pipe to trolley-jack pad and sawing resumes.

Pause for breath after much sawing, and discover that weird body position needed for sawing under car is now sending cut through pipe at 30° angle instead of vertical. At this angle I won't have enough oversized pipe remaining to fit over connector. Manage to get cut squared up again after much twisting of hacksaw, which fortunately does not break.

Sawing completes, end falls off, trolley jack is rolled out of the way and we have another look. Now have an inch or so of inner stub still needing to come out. More propane all around.

Thumping, yanking and prying of hot metal does nothing; inner core does not want to budge. Finally hit on bright idea of wedging inner and outer pieces apart around the edge, bending inner piece inwards enough to grip it with Vise-Grips, then twist it to reduce its diameter, which should free it from the pipe.

Much hammering with thin screwdrivers and rubber mallet opens up a small gap all around. Select oldest Sears Craftsman flat-blade screwdriver, the barely recognizable one with paint all over the handle, and pound it in the end where the inner pipe stub is the shortest. Careful prying inwards gets the stub starting to bend in, until too much careful prying causes screwdriver to carefully go *crunch*, and come out somewhat shorter than when it went in. Make mental note to bring screwdriver back to Sears for free replacement. Need to think of believable story so that staff does not think customer is an idiot.

Further bending gets edge turned up just enough to clip a small Vise-Grip on it. Metal is too tough to twist, and there'* nowhere near enough leverage for turning. Another bright idea: use the screwdriver we broke during our last bright idea, stick it sideways into the jaws of the Vise-Grip, and use that to twist the whole thing. This starts to work, right up until the twisting force yanks the Vise-Grip jaws sideways and its jaw hinge plates bend. Don't think Vise-Grips come with a lifetime guarantee.

Okay, the Vise-Grips will still work, but need to be clamped across the whole body of the wrench so that it can't distort when twisted. Fortunately, we have another pair, now clamped tightly at right angles across the first one, we grab the whole mess, and twwwiiissssstttt...

Major crunching noises... and suddenly the inner pipe stub starts turning! WooHoo!



It all comes right out, leaving a nice round outer pipe, all ready for a new connector. Total casualties: half a can of propane, one deceased screwdriver, and one pair of Vise-Grips that will never chew its food the same way again, but we're ready to start putting things back together at last.

This last part is a breeze: there'* enough oversized rear pipe remaining to get the connector seated and squarely clamped, and the front pipe fits perfectly into the oversized half of the connector. Some flexing around shows that the system will sag under its own weight an inch or two, so it needs to be actually touching the underbody before tightening the clamps, so that its subsequent sag won't let it hang too low.

Roll the trolley jack back under the car, to the midpoint of the * curve just forward of the connection, and lift the system with a block of wood until it'* hard up against the floorboards, tighten the two new pipe clamps good and solid, slowly release the trolley jack, and the system does its sag... just right, about an inch or so from the body, snuggled around its heat shields and stuff, nice and parallel.

First test! Hop in, twist the key... and it purrs. Nice and smooth. Quickly jack it up, yank the wheel ramp, lower the car, road test... sweet!

Okay, maybe the muffler will blow out next week; it'* probably had a light load for some time, since the pipe connection'* been leaking for who knows how long, but at least I fixed this crisis myself, got some exercise, only spent four bucks, and the car'* back to normal again. I like repairs that don't take forever; I just wish they didn't have to happen in the winter.
Old 03-12-2005, 05:32 PM
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I don't know what to say, Andy.

Old 03-12-2005, 07:34 PM
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Long and informative but where are the pictures?

Good article Andy.
Old 03-12-2005, 07:48 PM
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Originally Posted by ron350
Long and informative but where are the pictures?

Good article Andy.
I have one picture I took of the inner core after it was yanked out, while the two Vise-Grips were still attached. We still don't have photo hosting on the BC website, do we? If somebody else can give a 603K JPG a hosting home for the image for this thread, I'll email it to you...
Old 03-12-2005, 07:56 PM
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Check your PM'*. I replied.

I get to see it first!
Old 03-12-2005, 09:49 PM
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Originally Posted by ron350
Long and informative but where are the pictures?
Okay, okay, I think I'll have a chance tomorrow to jack up the car and get a shot of the finished job. WillWren'* going to be the photo editor here, I think...
Old 03-12-2005, 09:56 PM
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Sorry for the delay. I was busy breaking 2 chainsaws. Threw a chain, but no blood.
Old 03-12-2005, 11:40 PM
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Sorry for the delay...
Ah, there we go. Thanks, Will! That'* what I finally pulled out of the pipe this afternoon. Check out the jaw alignment on the Vise-Grips holding the pipe! That pair'* going to be just a little loosey-goosey from now on...
Old 03-13-2005, 12:11 AM
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That'* what you call an 'offset'. So it sounds intentional, and you can't be blamed for F-ing them up the next time the wife wants to use them.

Old 03-13-2005, 03:11 AM
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Hi Andy I was just kidding about the pictures, but that is one mean looking piece of exhaust pipe.

“Where are the pictures” and “you can never have too many pictures” was a running joke at a company I worked for once. That company did up grades for paper mills and they are mostly piping.


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