Metric hardware is not rated by grade, but by property class. The common
classes are 5.8, 8.8, 10.9, 12.9, and some real special stuff is 14.9. Yes
the exhaust studs are most liklely 5.8 or 8.8. Almost all repalcment studs
are 5.8 unless you go for a better spec.

Twist offs are the hardest to remove since it will be difficult to get a
drill bit started. Get an air grinder or Dremel and grind the end smoth and
use a good sharp punch to get a center dimple. Start with a 1/16" bit ans
work you way up. Be very carefull not to break the bit. A small right angle
air drill and removing accesrories will allow you to get in there. If you
are carefull and lucky you may be able to drill out the old botl and use a
standard tap to clean out and repair the hole. If you need to heli coil, the
new exhaust can e set in place and used as a guide. There is no need or
benifit to extra lenght or double inserts. The single coil will be more than
adequate to hold the bolt in place especially if using stainless. Note how
the heli coil lenght is almost the same as a nut.

IF goiing for Stainless hardware, look for 316 (A4). It performs slightly
better than the 18-18 (A2).
Stainless to Stainless connections always need a nickel based anit seize or
maybe loc tite as a lubricant to keep the threads from galling.

Dennis

>From: Cullen Stewart <cullberly@VERMONTEL.NET>
>Reply-To: Cullen Stewart <cullberly@VERMONTEL.NET>
>To: vanagon@GERRY.VANAGON.COM
>Subject: Header bolts broken
>Date: Mon, 25 Aug 2008 22:33:23 -0400
>
>The worst has happened. After very patiently removing the nuts and bolts on
>my wbx I twisted 2 off and still have 1 to go. They are flush with the head
>and have nothing to grab onto. What are my options with out removing the
>head. They are obviously not grade 5 or 8, but good old garbage grade 2
>considering they twisted off with a minimum amount off force. Is it
>possible to helicoil these while in the van?