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Thread: Stainless Exhaust Flanges Rotting Away: What Does the Future Hold?

  1. #1
    No mean-spiritedness here. IPreferDIY's Avatar
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    Default Stainless Exhaust Flanges Rotting Away: What Does the Future Hold?

    I was blessed with dual stainless exhaust in my hand-me-down 2000 MGM. It eventually developed an exhaust leak at the cat to H-pipe flanges, and the cause was the nuts rotting off. It seems Ford used regular nuts and bolts on a stainless exhaust. Unfortunately, the bolts were stuck in the holes, and I resorted to a BFH. After a crapload of pounding, the bolts came out, but I probably caused more metal to come off the bolt hole ears than a better method might have.

    Fast forward to more than a year later, and I decided to take off the heavy dampers. Regrettably, more metal was flaking off the flanges. I know stainless isn't completely impervious to rot, but it's disappointing to see it that bad. I'm not sure how much longer the bolt hole ears are going to hold out. For the sake of planning ahead, can anyone shed light on what gets done to fix flanges that are too rotted to function properly? On a prior car, I recall using some kind of two-piece flange that bolted together to take the place of a flange. Is something like that in the cards?

    On a related note, is there a difference between gaskets used on a stainless exhaust and a regular exhaust? When I did mine last year, I got two different types since that's what they happened to have. One held up fine while the other was crap. When I called about getting another pair, the guy at the counter said something along the lines of there being a difference between the gaskets for single and dual. I'm wondering if it's a matter of dual always being stainless and requiring a different gasket.

    2000 Grand Marquis LS HPP, a hand-me-down in 2008 with 128,000 km; 175,000 km as of July 2014
    mods: air filter box "tuba" (in place of the "trumpet"), headlight relay harness, J-mod (around 186,350 km), 70mm throttle body, NKL4 PCM (from a 2000 CVPI, nothing great there apart from highway cruising), KYB Gas-A-Just shocks (after >202,000 km on originals)

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    No mean-spiritedness here. IPreferDIY's Avatar
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    From what I saw at the parts store, single and dual have the same part number for the gaskets, so whatever the guy said about a difference must have been about something else. The prior mismatched pair was a matter of being from two different manufacturers rather than two different part numbers. I got a matching pair this time, and it looks like they're the better ones.

    When I first went to put them in, I noticed the gaskets would rock back and forth with the bolt holes as the pivot point on the cat side. I figured it was either the ears becoming bent or bulges developing from something like the stainless equivalent of rust bubbles. I seriously doubted that the gasket was thick enough to compensate for the resulting gaps, so I went about reducing the high spots. Taking a BFH to them to get the ears to bend the other way didn't seem like a good idea, and they didn't really seem to be bent to begin with, so I opted to file down the high spots. I was getting a lot of a funny red color, which I would guess is the stainless equivalent of rust. I got things to a point where holding the flanges together with the gasket showed a gap that was smaller than the gaskets, and it seems to be okay. My car's still on ramps since I'm doing lots of stuff, so I don't know how it runs yet. Hopefully it'll hold up for at least a few more years.

    2000 Grand Marquis LS HPP, a hand-me-down in 2008 with 128,000 km; 175,000 km as of July 2014
    mods: air filter box "tuba" (in place of the "trumpet"), headlight relay harness, J-mod (around 186,350 km), 70mm throttle body, NKL4 PCM (from a 2000 CVPI, nothing great there apart from highway cruising), KYB Gas-A-Just shocks (after >202,000 km on originals)

  3. #3
    drink a beer, grow a beard, cut it, grind it, weld it back His Royal Ghostliness's Avatar
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    The ears are bent, that's normal for 2-bolt flanges. Heck even the 3-bolt ones can suffer from it if they're not made thick enough (and most aren't).

    The red dust you saw was rust, no need to sugar-coat it. Stainless in factory exhaust is low-grade stainless, it will rust up just fine given the right conditions. Which apparently you have them where you live.

    To bend the ears back easier you can heat them up with a torch till they glow, then hammer away. But they'll eventually flatten back the way they came from, and hello exhaust leak. If they're thin enough this will happen while you're still tightening them. Planing the surfaces flat with the file was a good idea tho, that should help the gaskets seal.

    Btw the 2-piece clamp/flange i still available at parts stores. But it only works for pipes of the ball-socket connection, for what you have you need new weld-in flat flanges. Or you could use the clap-on ones, but you still gotta weld them to the factory down pipes (the ones with all the cats on them).
    The ones who accomplish true greatness, are the foolish who keep pressing onward.
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    Why waste time trying to fix rotten flanges? Chop them off then weld some new flanges in place and call it done. The h-pipe on factory stainless exhaust is made from lower quality steel than the tail pipes and mufflers so it rusts out faster. I see you are in Canada. If you can find Zoro muffler near you, they do stainless exhaust. They should be able to take care of your issue.

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    Thanks guys. It's good to know that flanges can be welded on. Now would not be a good time, but sometime down the road when I know it's coming would be tolerable. I went for a test drive and everything seems okay. Hopefully they'll last at least a few more years.

    2000 Grand Marquis LS HPP, a hand-me-down in 2008 with 128,000 km; 175,000 km as of July 2014
    mods: air filter box "tuba" (in place of the "trumpet"), headlight relay harness, J-mod (around 186,350 km), 70mm throttle body, NKL4 PCM (from a 2000 CVPI, nothing great there apart from highway cruising), KYB Gas-A-Just shocks (after >202,000 km on originals)

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    I was hoping to have this issue behind me today. Some weeks ago, I noticed a local exhaust shop while on my bike, and someone who seemed to know what he was doing said they could weld on new flanges for CDN$80-100. Today I was finally in a position to take my car in, but the fellow at the counter was someone who did not speak English well. He said they would have to weld in pieces of pipe because they would not be able to get the flanges aligned.

    Here's what they have on their website (with misspellings in capitals):

    Flange
    Here at Quick Muffler we have a wide range of flanges, two bolt, three bolt, four bolt and a wide range of other arrangement's, if we don't have what you need or if you WONT something out of the ordinary then we can help. With our ability to have flanges cut to any desired shape WEATHER it's for a dump pipe (plate on the turbo) or your custom manifold or extractors (plates on the head). Our laser cut plates ensure that they will be precise and neat, ideal for a show car or just if you want the best for your vehicle.
    I had dealt with a Zoro many years ago and was quite happy with their work and price, but they are significantly out of my way at this point. I've sent emails to two closer places but will go with Zoro if the other two don't work out.

    2000 Grand Marquis LS HPP, a hand-me-down in 2008 with 128,000 km; 175,000 km as of July 2014
    mods: air filter box "tuba" (in place of the "trumpet"), headlight relay harness, J-mod (around 186,350 km), 70mm throttle body, NKL4 PCM (from a 2000 CVPI, nothing great there apart from highway cruising), KYB Gas-A-Just shocks (after >202,000 km on originals)

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    It's normal for them to weld small sections of pipe to extend the exiting ones after they chop them off. Just make sure they use stainless pipe and stainless flanges. Most regular exhaust shops won't have that stuff in stock.

    I know Zoro in Hamilton keeps stainless flanges and pipes in stock and also have a mandrel bender.

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    No mean-spiritedness here. IPreferDIY's Avatar
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    This guy was talking about using pipe without any flanges (and without even having looked under the car). And he looked at me like I was the one who didn't know what I was talking about. (Unfortunately, I get way more than my fair share of that due to my eye alignment issues. Some insight into my issues can be gained from looking up "convergence insufficiency", which has very similar symptoms despite not being the exact same issue that I have.) I wouldn't have had a problem leaving my car there if parts had to be ordered, but doing things his way would have meant the H-pipe would have to be cut if it ever had to be lowered for some reason. I'm at a loss as to how it is they would be able to align it well enough to weld in pieces of pipe but not flanges. I'm guessing he was thinking the flanges would be welded on individually instead of while they're bolted together.
    Last edited by IPreferDIY; 06-18-2019 at 07:20 PM.

    2000 Grand Marquis LS HPP, a hand-me-down in 2008 with 128,000 km; 175,000 km as of July 2014
    mods: air filter box "tuba" (in place of the "trumpet"), headlight relay harness, J-mod (around 186,350 km), 70mm throttle body, NKL4 PCM (from a 2000 CVPI, nothing great there apart from highway cruising), KYB Gas-A-Just shocks (after >202,000 km on originals)

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    Sounds like the shop was just lazy and didn't want to do flanges. It's easier to just weld a straight piece of pipe in and call it a day. It works but no way for you to take the exhaust off without cutting it off.

  10. #10
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    Most shops will just weld it up without the flanges. Easier for them, sucks for you. For most people who just want the pipe to come out the back and don't care how it gets there, I suppose it just isn't that important.

    As for people looking at you like you don't know what you're talking about, just expect that to happen when you aren't interested in whatever excuse for half-ass work is presented to you.

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    Yeah, those of us who want things a certain way are an irritant to most shops anymore.

    Alex.

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    No mean-spiritedness here. IPreferDIY's Avatar
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    One of the two places I emailed wanted $240 for a flange job. (All prices here are CDN$ plus taxes.) The other did not respond. The Zoro in Mississauga would not provide an estimate without seeing the car, and I managed to get out there today. I don't see why doing flanges would be any harder than pieces of pipe (especially if the flanges already have a bit of pipe on them), but there must be something to it, as the fellow who brought me under the car wanted me to consider the pipe-only option after I told him I wanted flanges. Their flange price ended up being $200 while their pipe-only price was $160. After hearing $80-100 from the seemingly knowledgeable fellow at the other place, I had been open to the possibility of a little more than that, but not that much more. I've put this task on the back burner for now.

    2000 Grand Marquis LS HPP, a hand-me-down in 2008 with 128,000 km; 175,000 km as of July 2014
    mods: air filter box "tuba" (in place of the "trumpet"), headlight relay harness, J-mod (around 186,350 km), 70mm throttle body, NKL4 PCM (from a 2000 CVPI, nothing great there apart from highway cruising), KYB Gas-A-Just shocks (after >202,000 km on originals)

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    Have you tried a mufflerman? Some of them (not all of them) have in the past at least been more receptive to doing what you want. Scabbing in a pipe with a flange isn't any different than scabbing in a straight pipe...

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    $200ish sounds about right because you have to buy 4 stainless flanges, bolts, gaskets and then the labor. As I recall when I bought 4 stainless flanges alone from Zoro it was close to 100 bucks. Anything stainless and price rises exponentially.

    One other place you could try is Toronto muffler and brake (Hot Rod Scott's). They did complete stainless exhaust for my 96' back in the day which I am still rocking on the 85' with mods. It was quite reasonable but that was years ago.

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    Haha same shit happened when i got the exhaust done on the first box. I brought my headers, mustang h-pipe, and mustang "flow-tubes" with the ball-socket flange to attach to the h-pipe. Didn't notice 'til later that they cut the flanges off the back of the h-pipe and just welded it up. Shop closed not long after too. When the system goes on the current car, i'm putting v-bands on various sections so they can be removed. I despise people too lazy to do their job well.

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    I had a similar situation with my Aunt’s Hyundai Elantra. The flex pipe section on the mid pipe completely rotted off. When I got underneath, I noticed the rear flanges of the mid-pipe were just one glob of rust. I made a failed attempt to drill the bolts out and pull the pipe off. But countless drill bits later, I ended up cutting the flange and buying another flange and a stock mid-pipe. I deliberately left more than enough pipe for the replacement flange to slide over with the intention of cutting bits off for adjustment. I found that the flange slid over the stock exhaust pipe; which made adjusting and bolting the mid pipe much easier. I used band clamps to clamp it together. Came out good for $250.

  17. #17
    No mean-spiritedness here. IPreferDIY's Avatar
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    Quote Originally Posted by GM_Guy View Post
    Have you tried a mufflerman? ...
    It looks like their most easterly one is Cambridge (I'm in the GTA), but I'll be going to Stratford to see Shakespeare's rarely-staged "Henry VIII" (the asshole who killed his wives and took over the English churches and made divorce fashionable), so I'll stop in at a convenient one. I'd be surprised if they were significantly less than $200, and I wouldn't go out of my way to save a few bucks if $200 is reasonable, but it can't hurt to check. Maybe I'll get lucky and they will have lower prices due to being outside of the high-priced GTA. And maybe I'll be feeling better about cash flow by then in any event. Thanks for letting me know.

    Quote Originally Posted by Mr Bean View Post
    $200ish sounds about right because you have to buy 4 stainless flanges, bolts, gaskets and then the labor. As I recall when I bought 4 stainless flanges alone from Zoro it was close to 100 bucks. Anything stainless and price rises exponentially.

    One other place you could try is Toronto muffler and brake (Hot Rod Scott's). They did complete stainless exhaust for my 96' back in the day which I am still rocking on the 85' with mods. It was quite reasonable but that was years ago.
    Considering that one place said $240 (I would guess that place was comparable to Scott's), $200 was certainly an improvement. I imagine there's a lot of mark-up though. Ideally, I would like to re-use the stainless fasteners that I put on, and maybe even two of the best of the five or six (total) thin Victor Reinz (supposedly OEM) gaskets that I tried using to prevent any gaps during my latest futzing with it, but I can certainly appreciate why a shop would not do that (though I hope they would at least use anti-seize if I brought some). I don't have any meaningful welding experience, so NFC about time required, but if $200 is considered reasonable overall, I'll just work it into my future finances. I have U-joints on order and a bigger-than-usual monthly bill coming up (not to mention an annual income tax setback arising from my independent contractor work), so the flanges are not a priority.

    2000 Grand Marquis LS HPP, a hand-me-down in 2008 with 128,000 km; 175,000 km as of July 2014
    mods: air filter box "tuba" (in place of the "trumpet"), headlight relay harness, J-mod (around 186,350 km), 70mm throttle body, NKL4 PCM (from a 2000 CVPI, nothing great there apart from highway cruising), KYB Gas-A-Just shocks (after >202,000 km on originals)

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    No mean-spiritedness here. IPreferDIY's Avatar
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    I looked into this stuff a bit and found that a significant issue with doing flanges is warpage. There's also an issue of getting an undesirable weaking of the weld if the heated metal is exposed to normal air. I saw something about someone avoiding both problems by attaching a stainless flange to an aluminum flange that has a short bit of closed aluminum pipe through which argon can be introduced.

    Building on this, I came up with a couple of ideas that might be useful (if they are actually novel) for those who work in the field:

    1. In order to minimize the amount of argon needed, one could use some kind of rubber plug or whatever that could be inserted into the pipes and expanded to create a seal. By doing this, one could possibly even limit the argon to what is necessary to purge the air and then close the outlet without having to leave the argon flowing (which seems to be the typical method).
    2. For two mating flanges, one could create a really thick aluminim flange to which both stainless flanges could be bolted and into which argon could be introduced. Since argon is reportedly heavier than air, the inlet could be on the bottom and the outlet on the top.

    For our set-up, one could insert the plugs and weld the two flanges, then unbolt the flanges and take the plugs out. I suppose there might be alignment tweaking required for the other side, but I'm sure the people who already do this work could figure that out. I suppose one could even have both sides set up at the same time (i.e. four rubber plugs and two aluminum parts). I would think a thick enough gasket would compensate for any lack of perfection in the alignment that might result from using and removing the thick aluminum pieces.

    I imagine just the prep work would be a significant aspect of the job. If I was to try the ultra-cheap route of simply cutting off the flanges and clamping on joiners, I would resort to using a hacksaw while on my back. Does anyone know what the actual cutting process involves? My limited familiarity with welding has been in a machine shop setting where things are machined nicely, which obviously can't happen in this context.
    Last edited by IPreferDIY; 06-23-2019 at 10:00 PM.

    2000 Grand Marquis LS HPP, a hand-me-down in 2008 with 128,000 km; 175,000 km as of July 2014
    mods: air filter box "tuba" (in place of the "trumpet"), headlight relay harness, J-mod (around 186,350 km), 70mm throttle body, NKL4 PCM (from a 2000 CVPI, nothing great there apart from highway cruising), KYB Gas-A-Just shocks (after >202,000 km on originals)

  19. #19
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    There is no need to try and save argon, the argon needs to sheild your arc, whats happening on the other side of the material is irrelevant (other than wind).

    So what kind of flanges have you got anyway? Just the flange itself, or stub pipes with flanges attached? If the first, I can see why nobody wants to touch it, thats a pain.

  20. #20
    No mean-spiritedness here. IPreferDIY's Avatar
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    Here’s a video that explicitly demonstrates the results of using and not using argon on the backside of the weld, with the final ‘show and tell’ being around 11:10:



    Before that part, he also demonstrates an interesting weld-cleaning gizmo.

    What concerns me about the people who just weld in pieces of pipe is that it’s highly doubtful that they use argon inside the pipes. Dunno to what extent their welds would be weaker, but I would prefer it being done properly.

    Here’s an interesting video showing how much warpage one gets from even a 1/2" stainless flange despite using an aluminum block (with argon on the backside), with the final ‘show and tell’ being around 14:20:



    The flanges are not something I would bother bringing with me in this context. I would presume they would use whatever works for them.

    2000 Grand Marquis LS HPP, a hand-me-down in 2008 with 128,000 km; 175,000 km as of July 2014
    mods: air filter box "tuba" (in place of the "trumpet"), headlight relay harness, J-mod (around 186,350 km), 70mm throttle body, NKL4 PCM (from a 2000 CVPI, nothing great there apart from highway cruising), KYB Gas-A-Just shocks (after >202,000 km on originals)

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