6

I was changing the Exhaust Manifold on an '09 Chevy Malibu. When tightening the bolt with the new one on, I twisted the whole bolt and stud off. So I have a couple issues. The broken stud is now left on the back of my engine.

What should I do to fix this? Options considered: Remove the broken stud. If so how? Weld a nut, drill it out, etc. Leave it? There are 9 other bolts. Is that good enough to form a seal with 1 missing? Currently, it still leaks exhaust.

Another question here: Question2.

Improve this question
1
  • 1
    Picture of broken stud would be nice, ever situation is different
    – Moab
    Jul 29, 2016 at 21:47

2 Answers 2

Reset to default
5

You should definitely try to extract it.

Preparation:

  • Heat the manifold with a blowtorch
  • Jolt the bolt with a pin punch
  • Soak the bolt with bp-blaster or another penetrating oil

Removal

  • If the bolt is protruding: Place two nuts on it, counter them against each other and try to screw the bolt out.
  • If the bolt is protruding but not enough for the two nuts: Grind a small groove in the bolt, use a punch to hammer tangentially into the groove thereby causing the bolt to rotate counterclockwise.
  • Drill the bolt out. If you damage the threads: Drill the hole larger and use a "time-sert" or "ensat" thread insert.
  • This solution also exists, but it is dangerous: Drill a hole into the bolt. Then hammer a torx bit into it and try to remove the bolt. Attention: If the bit breaks your bolt is filled with a hardened steel inlay, not allowing a second chance.
  • The best method: Buy a screw extractor set, including a left cutting drill bit

Installing the manifold

To prevent other seized bolts: Be sure to use some anti-seize (cooper or ceramic paste) on the bolts. Attention: The recommended torque is for a dry bolt unless the instructions tell you to lubricate the parts.

Improve this answer
3
  • 2
    Small correction. The recommended torque is for a dry bolt unless the instructions tell you to lubricate the parts.
    – dlu
    Jul 29, 2016 at 22:02
  • I posted what actually worked in my situation below, but I'm giving you the answer, since I think it will be more useful to others coming here in the future.
    – Dylan Cross
    Aug 11, 2016 at 13:29
  • I'll also add. Use a torque wrench when reinstalling the manifold. The bolts are a beast to remove, but require a surprisingly low amount of torque to spec. If you don't have a torque wrench, make them snug, but don't put all your strength into it.
    – Dylan Cross
    Aug 11, 2016 at 13:31
2

After a lot of research, I decided to start by trying a pair of vice-grips on what was left of the stud. I cranked them down real tight, and it came right out.

If that didn't work I'd have been going down the route of drilling, welding, or other more terrible options.

Improve this answer

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .