I'm going to try soon when the exhaust section arrives but I'm thinking it could be tough going, it's the fact the protruding threads will be rusted. Are you able to clean these threads before you attempt to remove the bolts. Maybe a soft wire brush and some wd40 on the threads first?
Tips for removing exhaust manifold bolts?
- Thread starter jsmoke
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Soldato
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PlusGas, lots of PlusGas.
Do you mean studs and nuts, or bolts?
If studs and nuts..
The absolute best way is with an oxy/acetylene torch as it allows you to get the nut glowing red hot without heating the stud as well.
Failing that, a heat induction tool over the nut, but it'll heat the stud as well.
Or WD40 etc.
If studs and nuts..
The absolute best way is with an oxy/acetylene torch as it allows you to get the nut glowing red hot without heating the stud as well.
Failing that, a heat induction tool over the nut, but it'll heat the stud as well.
Or WD40 etc.
Suds and nuts. Should I put some rust remover on them first?
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There's a fair chance the nut and stud will unscrew from the head casting if the nut is really corroded to the stud. Of course brass nuts on mild steel studs are a better way to do things in the first place. But as someone said earlier, heat, applied fast from an oxy acetylene torch is as good a bet as any.
Oxy acetylene set ups are becoming less common in garages and oxy propane is much more common, but gives nothing like the heat intensity. Worst things for rusted manifold nuts are Porsches in my experience, they must make them from old bicycles. They are often unrecognisable as a nut even before a socket is applied.
Oxy acetylene set ups are becoming less common in garages and oxy propane is much more common, but gives nothing like the heat intensity. Worst things for rusted manifold nuts are Porsches in my experience, they must make them from old bicycles. They are often unrecognisable as a nut even before a socket is applied.
To be honest, I've found over the years that exhaust manifold bolts usually come out pretty easily as long as the nut hasn't rusted into a blob.
Clean off corrosion on the exposed threads of the stud and soak in a penetrating oil of some kind and you should be OK. Quite often the comple stud will just undo out the head anyway.
If they're really stuck then as above heat is your friend, and induction heaters are life savers for jobs like these.
Clean off corrosion on the exposed threads of the stud and soak in a penetrating oil of some kind and you should be OK. Quite often the comple stud will just undo out the head anyway.
If they're really stuck then as above heat is your friend, and induction heaters are life savers for jobs like these.
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Oof. Not great.
I'd be getting the remains of the broken stud out and replacing it. If that means drilling and tapping, so be it. If you can get it out with an extractor set then great.
You can try running it with just two intact but I reckon it'll leak.
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If it leaks exhaust gasses it will (or should) fail a legitimate MOT. In most cases broken exhaust manifold studs in the head need the head removing and them drilling out on a milling machine, or at least a pillar drill. Some. like RB25DET Skyline engines where a design flaw results in studs being sheared off due to longitudinal expansion of the one piece cast iron manifolds, are so commonplace specialists like myself have made drill guide jigs to allow in situ drilling out and Helicoiing of SOME of the broken studs, depending on accessibility.
Trying to do it free hand with a battery or small mains power drill will almost certainly create more work and grief than removing the head and letting someone with the right machinery and experience do it correctly. It could even scrap the head beyond economic repair.
Trying to do it free hand with a battery or small mains power drill will almost certainly create more work and grief than removing the head and letting someone with the right machinery and experience do it correctly. It could even scrap the head beyond economic repair.
MOT wise, it really depends how much it's blowing.
I'll usually just advise "minor leak of exhaust gas" unless it's really bad, but bear in mind it'll likely affect the emissions reading and fail that way.
Either way, not replacing the stud/s is far from ideal as it'll eventually burn the manifold gasket out, and you'll be back to square one.
Chris is absolutely correct in saying that it's possible to wreck the head if not done right.
That said, I was an exhaust fitter back in the late 80's early 90's and must have drilled and tapped a thousand snapped studs in situ, but I had the experience, plus there was a ton more room under bonnet than there is today.
Get it done by a professional
I'll usually just advise "minor leak of exhaust gas" unless it's really bad, but bear in mind it'll likely affect the emissions reading and fail that way.
Either way, not replacing the stud/s is far from ideal as it'll eventually burn the manifold gasket out, and you'll be back to square one.
Chris is absolutely correct in saying that it's possible to wreck the head if not done right.
That said, I was an exhaust fitter back in the late 80's early 90's and must have drilled and tapped a thousand snapped studs in situ, but I had the experience, plus there was a ton more room under bonnet than there is today.
Get it done by a professional
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MOT wise, it really depends how much it's blowing.
I'll usually just advise "minor leak of exhaust gas" unless it's really bad, but bear in mind it'll likely affect the emissions reading and fail that way.
Either way, not replacing the stud/s is far from ideal as it'll eventually burn the manifold gasket out, and you'll be back to square one.
Chris is absolutely correct in saying that it's possible to wreck the head if not done right.
That said, I was an exhaust fitter back in the late 80's early 90's and must have drilled and tapped a thousand snapped studs in situ, but I had the experience, plus there was a ton more room under bonnet than there is today.
Get it done by a professional
Indeed, I could tell Jon had real world experience, as an exhaust fitter, even back then he will have seen the worsening of car design, and have got to try and work around it
It depends on the engine and in what it's installed, on some set ups you can only feel for the fasteners in situ, or use a mirror, and need to make or buy unique tooling to undo them with the engine in place. Drilling them out and re-tapping oversize, or Helicoiling is totally out of the question without significant dismantling.
There are plenty of modern cars where something as basic as a starter motor or alternator change demands total engine removal
Problem is I've ordered a new exhaust to fit myself, nobody out there will fit customer suplied parts.Take to exhaust place, pay an hours labour, sit and chill in waiting room on ipad
just to add if its sheered off flush to the manifold then with the manifold removed there should be some exposed bolt left. get a external extractor on it and some wd40
Snap On A50 1/2 Drive 7/16 & 1/2 Stud Extractor
Sealey Impact Stud Bolt Extractor Remover Socket Tool 1/2" Drive 6-
i have these from my garage days make short work
Snap On A50 1/2 Drive 7/16 & 1/2 Stud Extractor
Sealey Impact Stud Bolt Extractor Remover Socket Tool 1/2" Drive 6-
i have these from my garage days make short work