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MG Midget and Sprite Technical - Exhaust downpipe repair. Bandage/wrap?

Got a small hole in my exhaust manifold downpipe, near the end where it joins to the rest of the exhaust.

Yep, I know, take it off and weld it for a propper job.

But I need a quick fix. So non-weld solutions only please.😉

How long will a wrap or bandage repair last?

Anybody done this?
What did you use?
How long did it last?
anamnesis

I am very surprised, Anam, that you are not already well experienced in this particular bodge. - A common roadside repair, surely?

I have had reasonable success with small holes by fitting a jubilee clip positioned to cover the hole, and then wrapping with that GunGum bandage stuff that you soak in water. For slightly larger holes the same, except position a bit cut from a tin can under the jubilee clip. Might get a couple of thousand miles at least from that. But less if it is on a joint subject to movement stresses.
GuyW

On the main part of the exhaust system or a silencer yep Guy. But I've never had to try fixing the downpipe of a manifold before. I imagine it will be so much hotter, and possibly more pressure.

I was wondering about using some manifold wrap.

The last time I used gungum, it wasn't as good as it was years ago. Seemed to just turn to powder after a while.
anamnesis

Anam

I have a roll of 50mm self-adhesive 'silver' foil tape, probably bought from the builders' merchant when installing insulation.

I have used it successfully on joints with small leaks and Mr MoT was happy. Preferable, I thought to using a paste that might gum up the joint and make it hard to disconnect. I'm not sure about the pressure and heat of the manifold but further down the system it's served the purpose.
C Mee

Thanks C Mee.

My leak isn't on a joint so no problem there. The silver foil roll sounds interesting, but I wouldn't think the self adhesive would be heat resistant enough on the manifold downpipe. Probably a mastic sealer of some kind.

I'll look on ebay and see what's on offer.
anamnesis

If it’s a small hole - self tapping screw then put some gum gum around it and gently heat with a propane torch for initial cure. Then add exhaust bandage wrap + tin can shaped/ gum gum as required to make a tight wrap.

R.
richard b

I need to get under it and see how big it is. I can see the soit and hear it. I think it's a split, more than a round hole.

I should say, it's not on my Sprite, but on my Capri. And because I'm selling it, I'm not inclined to buy a new manifold, circa 280 quid. I might yet end up welding it, but atc50 plus years old, it may be too 'thin' now.
anamnesis

Anam, if you're thinking of selling, an invisible or nearly invisible repair would be preferable.

A bandage repair would sound warning bells for me as a buyer: what other bodges are there that I can't see?

I agree that MIG welding would probably be too fierce (DAMHIK) but is there a welding company near you that does TIG welding? If it's just a small split the cost should be minimal.

Is the manifold steel tube or cast?

Colin
C Mee

Tube steel, so if thick enough it's weldable.

Yep, agreed, I'd tell any potential buyer that it's priced to include the manifold needing attention, or a new one. I have someone in mind, price semi agreed, but if he doesn't buy it, I may keep it for another year, and try migging it, or buy a new manifold. So easy to keep putting in money, and just not worth my while, as I can't put the price up to recover it. I'm selling it 'cheap' to reflect it needing a decent paint job.
anamnesis

Should have said. NMC. 😉


anamnesis

If you end up taking the manifold off I'd be more inclined to gas weld it.
Did it more times than I care to think about back in the day and don't remember any problems doing it on steel.
Cast iron is more problematic but still doable.
Even did it in situ on some cars.
For repairs further along the chimney I used to cadge useable bits of old exhausts from behind the local exhaust shop and use them as patches, always gas welded because that's all we had.

Plenty of places still have oxy-acet gear, even now.
Greybeard

If you take it off could you get a short length of pipe or bend up some - probably end up as two sections and weld on and weld up seams.
Agree gas would be best.
When ‘I were a lad’ in the garage where I usually just got in the way of an evening waiting for my car - standing about got you a job to do ! But reduced the bill, the he owner was an ace with gas - could weld anything to a very high standard - Mot/ exhausts vertical and ‘over’ the top of pipes.
I enjoy gas welding but no longer have the gear and not to his standard.

R.
richard b

I'll get under it later today for a better look and a prod to see how strong it actually is. There's a nearby old school garage I could ask about gas welding. Maybe if I get and fit some sleeve to it in preparation they might gas it for me. But it depends how much they'll charge of course. Now't cheap around here anymore for labour rates.

And if it is strong enough, and I've gone to the bother of taking it off, I might as well mig it myself.

Truth is, I'm bored with it. Lol. So a quick bandage bodge sounds better to me. 🙂

anamnesis

Trying to envisage where the hole is. In the past have used tin ie baked bean tin, or maybe in a more middle class household, chopped tomatoes tin. Wire-brushed around hole, smeared exhaust paste around affected area, wrapped tin around hole, held either end with U-clamps.

If cast iron, brazing might be best solution. Unlikely suggestion: is JB Weld heat resistant?

I take it this isn't an MG? Can you get a cheap secondhand manifold?
Peter Allen

Baked bean tin. Now there's a good idea. Heinz of course, not cheap own brand stuff. Middle class enough? 😁

Picture of Capri a couple of posts back.

I'll take a pic of the hole/split later.
anamnesis

Leak is on the collector. Small hole, but surprisingly loud.

And as the system has been altered to join to a custom made stainless system, with a larger bore, if I buy a new manifold, I'd have to weld that anyway to fit it.

The collector is oval shaped, not so easy to bandage and clamp I assume.

Guess that means manifold out and try migging it, -- since it's on the collector which seems it 'may' be a bit thicker.











anamnesis

Should be able to do that in situ, Anam.
GuyW

Probably. But I think I prefer th3 effort of taking it off, to welding under the car these days.
anamnesis

On a ramp with a gas torch...
60 seconds tops...
Greybeard

Yep, I'm with you Grey, there'd still be enough wire left from a coathanger to hang a small shirt ---- lol
Is that another hole up high in the pic on the inner pipe---

willy
William Revit

I wish I had a ramp, and gas. Checked local garage with gas, 75 quid per hour plus vat. But he said if I bring the manifold in he'd do me a price.

Well spotted Willy. I'll have a look. I hope it's not another hole. If it is, it must have rusted too far to bother trying to weld I think.

I've got a very keen buyer interested. I spoke to him on the blower again last night and asked him if he wants me to buy a new manifold and up the sell price, or if he'd rather I bodge it and leave it to him. He seems happy to gungum it for now.

But as I may well keep it and drive it myself for the summer, as he's not in a rush, as he's moving to Devon, I'm inclined to want a proper fix, even if it means a new manifold, because really, at 59 years, this manifold is moribund.🤪
anamnesis

Fortunately not another hole. A bit of plastic washer tube had dropped down and turned to a black mess.
anamnesis

Welding it is the best option, your local guy should be able to weld it on there in a couple of mins--At 75/hour it shouldn't take any more than 10 mins all up 15 pounds
If you're going to pull it off it should be less
or
Found this for a bodge up--
https://www.ebay.co.uk/p/17032259344?iid=234545152802
William Revit

I would have thought something like Sairset or Triset air setting refractory mortar might be a better option and I expect if you asked around local potters or glass blowers you'd find someone that could provide some. Apply and then leave overnight to set. If you were local I could have let you have some.

Regarding bodges/repairs I helped my neighbour repair the cat box on his Volvo 940 as the front had become holed. I gave him some Maftec refractory blanket and some 0.05mm stainless steel tool wrapping foil and he covered the damaged area with the Maftec then covered that with the foil and held the lot in place with some long jubilee clips so the foil is wrapped around the lower front half of the cat housing. His MOT tester didn't even comment. He could have gotten a new cat but it would have cost more than the Volvo was worth although he did say they're now starting to increase in price. Maftec is a 1600C classification temperature rated mullite fibre insulation blanket and is one of the materials used to support the cat ceramic core in its casing so well up to long exposure to hot exhaust gases.
David Billington

The jb weld stuff looks good Willy, reference for the future.; didn't know about that.

And never heard of the glass stuff either David.

But anyway, given that my buyer isn't too fussed, I think he maybe contemplating an engine swap and sell the 1500gt lump, I've decided to try a wrap, exhaust repair paste, and clips. All up 10 quid. If it lasts me a couple/3 months, all well and good.
anamnesis

The metal looks thin around the hole, I think its going to be tricky to weld without blowing holes in it.
Chris Madge

If you cannot get it gas welded, then I still think a passable temporary repair can quickly be done. Put a layer of gun gum over and around the hole and then fix a bit of thin steel over it, held in place with a jubilee clip. The steel needs to be thin like a bit from a tin can, so that it bends around the pipe as the clip is tightened. If you can find it, a further wrapping of gun gum bandage over the top and edges of the steel patch would smooth it out.

It may not look pretty but if the plan is to use it for a couple of thousand miles this summer and the buyer that you have lined up has other plans anyway then a low cost temporary solution should be enough.
GuyW

Had a 1962 Mercedes 190 with a small hole in the exhaust manifold. Used oven tempered aluminum foil folded over several times and fashioned a metal cover from a tin can. Used a Jubilee clip to attach the custom patch to the manifold. Worked very well.

Cheers

Gary
1979 MGB
Gary Hansen

Agreed Chris, it does look a bit thin. My prod and tap test says not thick enough for mig, but gas would probably be ok.

I'm going for a wrap.

Yep, Gary, Guy. I've now got the stuff to do pretty much what you say, including the oven ready ally foil which comes with the bandage. Only £2.89 from euro car parts.

Got gungum bandage, jubilee clips and an empty bean tin.; Heinz for quality. 🤣.

This stuff should do it, and the repair paste will come in handy for future use, as my Sprite is blowing on a joint somewhere; been meaning to sort that for ages.

Edit. Very good value, assuming it works. There's 4ft of bandage there, enough for a silencer. I'll easily need less than that, leaving some for another pipe repair.




anamnesis

Thank goodness for that, Anam. I was beginning to worry that you had lost your sense of adventure!

Now to complete the challenge you need to find a dusty potholed layby or "caff" lorry park and then carry out the repair with just a bent screwdriver and a stiff pair of pliers. And no jack!
GuyW

😆😆😆. Bloody hell Guy, I'm surprised you didn't suggest I do it in the rain, or wait till the winter for it to snow. 😁
anamnesis

And bang on cue, it's raining this morning.
anamnesis

It's messy, but it's holding.

Opened hole a bit to insert a couple of threads of a cut down self tapper.

Then wrapped and clamped, with due amounts of bandage and holts exhaust paste.

Nope, screw hasn't come loose to cause unknown rattle. It was the pre-existing rattle, that alerted me to the exhaust manifold hole whilst trying to find said rattle.

P.S. All done on my back. Too old for this malarky. Lol






anamnesis

That’s bodgetastic!
M Wood

Exhaust paste / Gun Gum, smooths over really well if you dampen the surface and then smooth the rough edges with wet fingers. But then, who cares what it looks like!
GuyW

That is smoothed Guy. 😅.

Who cares? Clearly not me. 😁.
anamnesis

This thread was discussed between 14/05/2022 and 01/06/2022

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