You need to grind down as little as possible to get the tin off, then
pull the pipe off. You should be able to use a conical remover to get
the stud out, they sell them at parts stores, home depot and the like.
Or us a small pipe wrench. Or slot it with a hacksaw and try to screw
it out.

You can put a patch in place on your tin with strap steel from a
hardware store when you put things together. JB weld the strap to the
tin after hitting a patch on the tin with a grinder for adhesion and
fresh metal.

Jim

On Sun, Jun 28, 2009 at 3:39 PM, Jeff
Hartman<jeffreyleehartman@gmail.com> wrote:
> Hi, I want to thank list members who helped me find the correct oil pressure
> sender for my 86 vanagon.
> The good news: The new sender and washer has completely stopped my oil leak
> with no apparent damage to the engine which was 2.5 quarts low when I
> discovered the leak.
> The bad news: When I removed the heat shield, to get to the oil pressure
> sender I discovered that a previous owner (or repair shop) installed the
> front driver side exhaust headers by welding the stud directly to the
> exhaust flange. �I had previously assumed the hex nut was just badly
> rusted. �When I started to wire brush it (hoping the rest of the nut would
> disintegrate leaving the harder stud in tact, nice shiny welds around the
> perimeter of the stud appeared directly welding it to the exhaust flange and
> bracket for the heat shield.
>
> I attempted a couple of times to write the list for advice about what to do
> next (because I would like to replace the exhaust pipes), but every time I
> tried, till now, I got so upset at the unknown person that installed it that
> way I couldn't complete the email. �Several days, and deep breaths later, I
> am finally ready to ask for advice again from anyone who has a suggestion.
> The upper stud has been welded to the flange in the same way too. �I haven't
> looked at the passenger side front head yet. �I can send an image of the
> welded stud if that would help, but I am stumped again.
> Thanks for the umpteenth time for any ideas,
> Jeff Hartman
> Juneau, Alaska
> 1986 Vanagon 2.1 L
>