Thermostat housing stud replacement

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Jul 10, 2007 | 10:42 PM
  #1  
The one stud that the water neck mounts on is broken in my manifold. There is still a little bit of the remains of it that is above the manifold but it isnt enough to be able to secure the housing to it. What would be the best/easiest way to remove and replace it?
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Jul 14, 2007 | 08:37 AM
  #2  
Re: Thermostat housing stud replacement
Heat, penetrating oil, left-hand twist drill bits, and extractors usually help to remove broken studs.
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Jul 14, 2007 | 09:23 AM
  #3  
Re: Thermostat housing stud replacement
Grind or file it flat; center punch it as accurately as possible; drill it out as perfectly straight and centered as possible using successively larger drill bits, like 1/16", 3/16", 5/16", then the final size; and Heli-Coil it. Replace the stud or bolt with the identical original hardware.

DO NOT use an EZ-out or similar screw extrator!!!! Please save us from having to answer yet another post about "it broke off in there and is harder than any drill bit I can buy, I've already ruined about a dozen drill bits trying to get rid of it, what do I do now".
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Jul 14, 2007 | 12:24 PM
  #4  
Re: Thermostat housing stud replacement
No argument here. I didn't write "E-Z-Out", I wrote "extractor" instead. "E-Z-Out" is in essence the Wal-Mart version of a real screw extractor, just like "Heli-Coil" is the Wal-Mart version of a real thread insert - Just a little better than J-B Weld. Use a tap wrench on the extractor so you have some control.

If things go really badly for you and the extractor (straight flute) doesn't move it in conjunction with the aforementioned penetrant and heat cycles, you may have to drill it up and re-tap it or install a thread insert. Use a full thread insert if you have the space (and you should have PLENTY of space for a thermostat housing). If you really feel like you want a spring coil thread insert (which is more suited to a tighter area like a transmission valve body), look for Chryslynn Precision or some more well designed thread insert spring than a Heli-Coil. That way, you can get the insert in exactly whatever thread length you may need, instead of whatever Heli-Coil decides they want to sell to the marketplace.

The Davenport Duke is correct. We don't want to see yet another thread asking about how to use a tap burner or EDM. Know the breaking point of your tooling and don't exceed it. If you have doubts, take it to a machinist (NOT a mechanic).
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