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More Bolts
Posted by JD From LA (more from JD From LA) on Fri, 1 Apr 2005 08:49:16
In Reply to: Re: Bolts do not snap from loosening, only over tightening, Mitja, Fri, 1 Apr 2005 03:45:11
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Usually a head bolt shears on loosening for two reasons. First the bolt was tightened past its yield point. Second, the bolt hole goes into the water jacket and no thread sealer was used so it rusted into place.
Unless the PO was totally clueless, overtightening is not a problem. Presumably, anyone swift enough to pull a head knows enough to use a torque wrench. The second problem is more prevalent, especially if the leaky head gasket has been leaking into the head bolt area. Of course, if you had good coolant in there, it shouldn't rust due to the added corrosion inhibitors.
So snapping head bolts is more indicative of a car that has been mistreated or sitting for a long time. If you use your car normally, the many heating/cooling cycles will help keep the threads clear and assure you your head bolts won't snap.
If you're still worried, spray the bolts liberally with penetrant the night before you start the job, then rap the heads a couple of times with a hammer and drift. The vibrations from tapping the bolt heads helps the penetrant wiggle past the threads.
JD
posted by 209.178.131...
Posts in this Thread:
- Fear of breaking head bolts, Mitja, Thu, 31 Mar 2005 22:48:40
- if you are paranoid now...., Saabu
, Fri, 1 Apr 2005 14:17:17 - Re: Fear of breaking head bolts, bj, Fri, 1 Apr 2005 08:58:27
- Re: Fear of breaking head bolts, diskullman, Fri, 1 Apr 2005 04:15:07
- Bolts do not snap from loosening, only over tightening, Jeff Cunningham, Fri, 1 Apr 2005 02:53:34
- Re: Bolts do not snap from loosening, only over tightening, Mitja, Fri, 1 Apr 2005 03:45:11
- More Bolts, JD From LA, Fri, 1 Apr 2005 08:49:16 <-- Viewing This Message
- Re: Bolts snap, Andy
, Fri, 1 Apr 2005 08:06:42
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