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Thread: Pre-cat exhaust studs

  1. #1
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    Pre-cat exhaust studs

    My downpipe (from pre-cat to cat pipe) flange on the cat side) broke off, and so I'm replacing it. I was able to get the old one off, but one of the studs in the pre-cat broke. It appears to be an M10x1.25 stud, but I have no idea how to get it out. I tried putting a nut on and welding it, but I can't get ANY penetration into the stud, probably because it's overhead and the weld pool wants to run away from the stud. As soon as I try to turn it with any torque the nuts just breaks free. Anyone have any suggestions as to how to get it off, and what is the appropriate replacement size? I've hard 35 mm is probably about right. If I can't get it off, how bad will the leak be with just two nuts, and is there anything I can do to seal it better?

  2. #2
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    Drill it all the way through, and put a bolt and nut in it's place.

    The other option is to remove the manifold/precat and get a better weld onto the stud.
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  3. #3
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    Quote Originally Posted by MrGiggles View Post
    Drill it all the way through, and put a bolt and nut in it's place.

    The other option is to remove the manifold/precat and get a better weld onto the stud.
    Drill it out and extract it, install new stud.

    Drill it out completely, install bolt, nut and washers.

    Weld a stud to it, grind weld down.

    Purchase new converter assembly.

    Those are your options...
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    I'm not particularly keen on removing the precat for fear I'm going to break another stud off in the process and just make matters worse. I guess its conceivable that I could try to weld from the above the nut although there isn't much room, but it might not have the same penetration problem.

    I saw someone drill into the stud before welding it, that might help, but he wasn't doing out overhead.

    The top of the stud area is a bulge, I'm not sure you could easily put a bolt through it, although its always possible I could drill and tap it.

    I'm not clear what the point of welding a stud to the stud would be. If I'm trying to extract it, I'd be better off with a bolt. The only advantage to a bolt or stud is that the pool may be more manageable, but it also seems like it's unlikely I could properly center it.

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  6. #6
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    Quote Originally Posted by hpmaxim View Post
    I'm not particularly keen on removing the precat for fear I'm going to break another stud off in the process and just make matters worse. I guess its conceivable that I could try to weld from the above the nut although there isn't much room, but it might not have the same penetration problem.

    I saw someone drill into the stud before welding it, that might help, but he wasn't doing out overhead.

    The top of the stud area is a bulge, I'm not sure you could easily put a bolt through it, although its always possible I could drill and tap it.

    I'm not clear what the point of welding a stud to the stud would be. If I'm trying to extract it, I'd be better off with a bolt. The only advantage to a bolt or stud is that the pool may be more manageable, but it also seems like it's unlikely I could properly center it.
    I gave you your options, it's your decision. IT'S A BROKEN STUD, not brain surgery. Just remove the converter. It'll make your repair that much easier. If another stud breaks, so be it, at least it's out and easily manageable at that point.
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