Exhaust leak at coupling - how to repair/replace?
Discussion
Hi everyone,
The MOT for my 2009 Hyundai Coupe is booked for next week so, naturally, issues that have kept a low profile all year have decided to finally make an appearance. In this case it is an exhaust leak at the coupling between the backboxes and mid-section. To be fair, as you can see in the photo this is clearly a story has been slowly playing out for a few years now and so really we're just on the final chapter!
Beyond replacing the odd flexi over the years I don't have much experience of exhaust repairs so would welcome advice about what my options are. Notwithstanding my ignorance on such matters, these are my thoughts so far about options:
1) Bodge a repair to get it through the MOT e.g. some exhaust repair past pushed into the holes and then maybe the thing wrapped up with something? I am assuming that as far at the MOT goes, 'no leak = Pass', regardless of how ugly the repair is?
2) Cut the nuts/bolts off (maybe I could snap them off with my fingers given the state they're in!) and the flanges than bolt in a coupling of appropriate size. My main concerns here are the awkwardness of getting an angle grinder in (would one of those 'chain' exhaust cutters be easier?) and also the change in piper diameter and proximity to the bends making things more awkward than they otherwise would be with a straight constant-diameter pipe.
3) Replace the mid-section and backboxes. Would rather not go down this route given the lack of availability of parts now, and that I don't expect to be keeping the car for more than a year or so as there are other pressures to get a new car anyway.
Incidentally, speaking of the backboxes, there are two of them which I am assuming will make taking them off the car (if required, e.g. to cut things off on the bench) will be more difficult than a single one as the pipe is routed over the rear crossmember and it'll need a bit of jiggling around to remove.
I would welcome any suggestions and advice.
The MOT for my 2009 Hyundai Coupe is booked for next week so, naturally, issues that have kept a low profile all year have decided to finally make an appearance. In this case it is an exhaust leak at the coupling between the backboxes and mid-section. To be fair, as you can see in the photo this is clearly a story has been slowly playing out for a few years now and so really we're just on the final chapter!
Beyond replacing the odd flexi over the years I don't have much experience of exhaust repairs so would welcome advice about what my options are. Notwithstanding my ignorance on such matters, these are my thoughts so far about options:
1) Bodge a repair to get it through the MOT e.g. some exhaust repair past pushed into the holes and then maybe the thing wrapped up with something? I am assuming that as far at the MOT goes, 'no leak = Pass', regardless of how ugly the repair is?
2) Cut the nuts/bolts off (maybe I could snap them off with my fingers given the state they're in!) and the flanges than bolt in a coupling of appropriate size. My main concerns here are the awkwardness of getting an angle grinder in (would one of those 'chain' exhaust cutters be easier?) and also the change in piper diameter and proximity to the bends making things more awkward than they otherwise would be with a straight constant-diameter pipe.
3) Replace the mid-section and backboxes. Would rather not go down this route given the lack of availability of parts now, and that I don't expect to be keeping the car for more than a year or so as there are other pressures to get a new car anyway.
Incidentally, speaking of the backboxes, there are two of them which I am assuming will make taking them off the car (if required, e.g. to cut things off on the bench) will be more difficult than a single one as the pipe is routed over the rear crossmember and it'll need a bit of jiggling around to remove.
I would welcome any suggestions and advice.
Cut the flange out add one of these?
Look at this product that I found on google.com https://share.google/937LoJZp3FkWABhVZ?
Look at this product that I found on google.com https://share.google/937LoJZp3FkWABhVZ?
duncancallum said:
Cut the flange out add one of these?
Look at this product that I found on google.com https://share.google/937LoJZp3FkWABhVZ?
Whenever I see those coupling they're always shown in straight lengths of pipe, do you think it'd still work in this scenario where it seem to be quite load bearing? I am also conscious of the length of the couplings as there's only so much of the 54mm pipe section available to clamp onto and seal against.Look at this product that I found on google.com https://share.google/937LoJZp3FkWABhVZ?
hengti said:
Maybe an olive joint although looks as though welding might be difficult. How much is a new system?
They're no longer available from Hyundai so I think I'd have to get something fabricated. Or wait for a used one to crop up on the eBay or an owners forum etc. There's actually one on eBay at the moment for £255 which I thought was a little steep but then of course it is the only one so it's seller's market.Just gave things a scrub with a wire brush and I feel like the pipework isn't as bad as I first thought, but the coupling and bolts clearly are:
I am tempted to see if some exhaust repair paste might be enough to get me through the MOT to buy me some time, then grind the bolts out, clean everything up and see what I'm left with in terms of what options might then be available to recreate a gas tight coupling.
I am tempted to see if some exhaust repair paste might be enough to get me through the MOT to buy me some time, then grind the bolts out, clean everything up and see what I'm left with in terms of what options might then be available to recreate a gas tight coupling.
I was toying with the idea of suggesting two flared replacement end pieces - weld one to each pipe then use an olive & a clamp - but playing on google came up with this. Never used them but it looks like that might be the best answer.
https://exhaustpartsuk.com/product/exhaust-repair-...
https://exhaustpartsuk.com/product/exhaust-repair-...
Edited by paintman on Sunday 5th October 19:23
Thanks Paintman. Yeah, that looks like a possible option.
I wonder if there's a variant that I could clamp each end (rather then weld) just to make it more DIYable.
Edit: I suppose I could cut my own slots in the end to allow some compression movement and put clamps round them?
I wonder if there's a variant that I could clamp each end (rather then weld) just to make it more DIYable.
Edit: I suppose I could cut my own slots in the end to allow some compression movement and put clamps round them?
Edited by tux850 on Sunday 5th October 19:28
I'm also looking at a straightforward clampable coupling:
It is approx 100mm in length so might be a little long if I want to keep everything in the exact position it is in now but I could possibly trim one or both ends once offered up to fit.
I am assuming the clamping sections are purely to provide a mechanical fixing and won't be contributing to forming a gas-tight seal - that being provided in the solid centre sections? So, as long as my 54mm pipe section are a snug fit in the middle then even if the clamping sections overlap the 50mm pipe it should hopefully still work?
It is approx 100mm in length so might be a little long if I want to keep everything in the exact position it is in now but I could possibly trim one or both ends once offered up to fit.
I am assuming the clamping sections are purely to provide a mechanical fixing and won't be contributing to forming a gas-tight seal - that being provided in the solid centre sections? So, as long as my 54mm pipe section are a snug fit in the middle then even if the clamping sections overlap the 50mm pipe it should hopefully still work?
tux850 said:
I'm also looking at a straightforward clampable coupling:
It is approx 100mm in length so might be a little long if I want to keep everything in the exact position it is in now but I could possibly trim one or both ends once offered up to fit.
I am assuming the clamping sections are purely to provide a mechanical fixing and won't be contributing to forming a gas-tight seal - that being provided in the solid centre sections? So, as long as my 54mm pipe section are a snug fit in the middle then even if the clamping sections overlap the 50mm pipe it should hopefully still work?
That is what I was referring to when I said to get it sleeved.It is approx 100mm in length so might be a little long if I want to keep everything in the exact position it is in now but I could possibly trim one or both ends once offered up to fit.
I am assuming the clamping sections are purely to provide a mechanical fixing and won't be contributing to forming a gas-tight seal - that being provided in the solid centre sections? So, as long as my 54mm pipe section are a snug fit in the middle then even if the clamping sections overlap the 50mm pipe it should hopefully still work?
Thanks E-bmw.
Got some JB-Weld ExtremeHeat arriving today (reassuringly expensive at £9.50 for 85g!) and once I've re-measured up the now cleaner pipes I will order a sleeve as you can't beat having something like that actually in your hands to offer it up and see if/how it will fit.
In the meantime I've rescheduled the MOT for next Monday (if there's one good thing about using Kwik Fit for MOTs it is that you can mess around with your booking times like this online to your heart's content and avoid messing them around on the phone!).
Got some JB-Weld ExtremeHeat arriving today (reassuringly expensive at £9.50 for 85g!) and once I've re-measured up the now cleaner pipes I will order a sleeve as you can't beat having something like that actually in your hands to offer it up and see if/how it will fit.
In the meantime I've rescheduled the MOT for next Monday (if there's one good thing about using Kwik Fit for MOTs it is that you can mess around with your booking times like this online to your heart's content and avoid messing them around on the phone!).
Oh, yeah, I was a bit ambiguous with that. The JB-Weld was just to see if it'll suffice to plug the current hole to get it through the MOT and then I'll do the 'proper' repair (with the coupler sleeve and normal exhaust paste as you say) in slower time. I figured if I plug the hole and it stays in place for a couple of days with no leaks then it should be safe to take the MOT. I could even *not* drive it around and just need it to last the couple of hours for the MOT!
Edited by tux850 on Monday 6th October 14:00
I've applied some JB-Weld ExtremeHeat and it looks great awful but once it's cured will see whether it's enough to buy me some time.
It was runnier than I expected but not quite thin enough to be naturally drawn into the hole/crack through capillary action. In an attempt to help ensure I wasn't just painting a layer over the top I stuck the vacuum cleaner in one tailpipe and blocked the other with a rag and that seemed to help give some pull from the inside whilst I was pushing from the outside.
I just hope it doesn't wind the examiner up! Can things be failed based on an opinion of a repair being deemed likely not to last, even if it is holding up at the time of the test? I guess bodges shouldn't be encouraged and so if it does fail, well that's fair enough I suppose.
It was runnier than I expected but not quite thin enough to be naturally drawn into the hole/crack through capillary action. In an attempt to help ensure I wasn't just painting a layer over the top I stuck the vacuum cleaner in one tailpipe and blocked the other with a rag and that seemed to help give some pull from the inside whilst I was pushing from the outside.
I just hope it doesn't wind the examiner up! Can things be failed based on an opinion of a repair being deemed likely not to last, even if it is holding up at the time of the test? I guess bodges shouldn't be encouraged and so if it does fail, well that's fair enough I suppose.
Edited by tux850 on Wednesday 8th October 20:04
It failed!
Not on the exhaust though (yay!) but excessive wear in a wishbone ball joint (damn it). Frustrating as the wishbone is only a couple of years old and has done less than 20k miles. I guess that'll teach me to buy cheap pattern parts (Borg & Beck in this case). I've pressed the old ball joint out and have ordered a new one. You'd think I'd learn - bought another Borg & Beck! I figured it was the safest bet though to ensure it would definitely fit the arm.
Not on the exhaust though (yay!) but excessive wear in a wishbone ball joint (damn it). Frustrating as the wishbone is only a couple of years old and has done less than 20k miles. I guess that'll teach me to buy cheap pattern parts (Borg & Beck in this case). I've pressed the old ball joint out and have ordered a new one. You'd think I'd learn - bought another Borg & Beck! I figured it was the safest bet though to ensure it would definitely fit the arm.
Edited by tux850 on Tuesday 14th October 00:15
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