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Okay folks, so I have here an exhaust manifold from a 1989 Volvo 240. I was able to disconnect it from the downpipe without breaking all but a single bolt. I snapped about a quarter inch from the manifold, so I couldn't really get any leverage with a stud extractor (since I would need at least an inch). I bought a screw extractor and used the provided drill bit to drill through the broken bolt. However, I am finding it difficult to turn the extractor. The handle for my taps don't quite give me enough leverage, and this screw extractor doesn't exactly work with an impact wrench. I've tried a pretty large adjustable wrench, and that didn't help either.

Does anyone have any ideas on how I can turn this thing? I'm thinking I might have to make something so I can turn it with an impact wrench, but beyond that I don't know. The square end of the screw extractor is about 6.5 mm wide, from face to face.

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  • Are you able to remove and re-insert the extractor? The stud should have broken free by this point. I suspect that you'll be removing the extractor, drilling out the opening and installing an insert.
    – fred_dot_u
    Commented Sep 19, 2018 at 22:31
  • Welcome to Motor Vehicle Maintenance & Repair! I think your best bet is to continue to drill, a little at a time. You'll get to the point where the stud will be thin enough it should peal out of the threads. If it doesn't, you next bet would be either using an insert as fred was saying, or to drill it out far enough to put a bolt all the way through and securing it with a nut on the backside.
    – Pᴀᴜʟsᴛᴇʀ2 ♦
    Commented Sep 19, 2018 at 22:55
  • Could try gripping the square in a vice and carefully rotating the manifold. You may need help to hold the manifold while you tighten the vice.
    – HandyHowie
    Commented Sep 20, 2018 at 1:20
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    If you break the extractor (with the vice method) you will really be in trouble. I would back out the extractor, heat the area orange-cherry, and then try to use the extractor with hand tools only.
    – SteveRacer
    Commented Sep 20, 2018 at 1:53
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    It does look as if that extractor is too large when compared to the other holes... You shoukd use an extractor that is about 2/3 of the stud diameter, if that extractor continues it will bind on the manifold material.
    – Solar Mike
    Commented Sep 20, 2018 at 4:42

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Using extra torque methods on extractors can be risky. The material is very hard and if it snaps in the hole it is nearly impossible to drill out or remove. The flange appears wide enough to accept a bolt. I would drill the stud out and replace it with a thru-bolt. My preferred method is to use a good quality grade 5 bolt with a grade 8 nut. My reasoning for this is the grade 5 bolt is strong enough to clamp the flange, but is soft enough that it can be easily cut if it needs to be removed later. The grade 8 nut is more rust resistant which will make it easier to remove years later. As others have commented apply a liberal amount of anti-seize to the hardware.

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The traditional way of removing this is with heat. You will really want a blow torch. Heat area until bolt is pretty much glowing red (about 1000 deg). Spray area with WD40, ... it should weep into cracks. Done properly the bolt will come out as if it was greased... You might want to swing by a machine shop or repair shop if you've never done it or don't have a blow torch. Plumbers torch will take too long to heat. There inductive heaters made for this sort of thing.

However, it looks like you did a pretty good job centering the drill. Drill a little bit larger and follow up with a tap. If necessary, go a bit larger and use a thread restorer.

When you reassemble, use plenty of high temp anti-seize (nickle based?) and use a stainless steel bolt. It might work.

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    I think the problem now, with it drilled out, there's not going to be anything to heat except the manifold itself. You could heat it to cherry red and put some beeswax on it (WD40 might work), but I think you might run the risk of cracking the manifold from the abrupt temp change.
    – Pᴀᴜʟsᴛᴇʀ2 ♦
    Commented Sep 20, 2018 at 0:44
  • That wax method is very old school, but I've seen it done and it works very well. I think WD40/PB Blaster penetrating oils may be to thin, and tend to flash off from the heat before they can do any work.
    – SteveRacer
    Commented Sep 21, 2018 at 9:48
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Take out the extracted and use a series of left hand drills to drill it out until it unscrews,I've had a lot of luck with left hand drills. You can get a cheap set of left hand drills from Harbor Freight tools.

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