Snapping head bolts - Mercedes-Benz Forum

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post #1 of 2 (permalink) Old 04-12-2008, 09:01 AM Thread Starter
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Date registered: Aug 2007
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Snapping head bolts

Hi all,

The repair of my C250D continues to be an enigma to me

Today I went to fit the reconditioned head with a new gasket set, all was fine until I wen to torque down the bolts -

I progressively went in sequence tightening the bolts 4/5 times with the (new) torque wrench set at 5ft lbs the lowest it will go, (Haynes recommend 11ft lbs for stage one) I kept tightening but nothing, the wrench didnt 'click' instead one of the bolts snapped

Picture below is of the bolt and wrench (setting has moved at bit but it was on 1) The bolts are not new as they are within 1mm of the stretch tolerances.

Last edited by spock500; 04-12-2008 at 09:05 AM.
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post #2 of 2 (permalink) Old 04-13-2008, 06:27 AM
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Date registered: Dec 2006
Vehicle: 2006 B 200 & Audi A6..
Location: Lake in the woods... Canada
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What size of bolts are they and what is the recommended torque?
You're showing more than 1 broken head bolt.
For 5 ft/lbs??....... How hard were you pulling on the torque wrench!!
You should have a feel that you're pulling to hard.
Your pics show necking at the fracture site and you can see the threads stretching before the actual failure.

Time for a new torque wrench!! Good Luck!!

It's much easier for all if you post pics of 800x800 and then we don't have to scroll into our neighbors yard to view them.
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