HEAT ... all your hot coolant hoses/pipes are "up there"....
which still oxidizes rubber and would definitely (could) affect
the bead. I'd suggest either finding a tube to put in it or fill it with
green
slime in it, and rotate the tire with that leaking-bead side down, so the
slime can seal your leaky bead, then re-stow it. May want to leave it
sitting for 24-48 hours with the slime in it with the leaky bead side down.
By the way, at 10 years the clock has run out on that tire being roadworthy.
"excellent" shape doesn't have much to do with tread depth. Many, if not
most
tire mfg companies recommend replacing tires every 6 years ... ten is a
stretch.
By the way, keeping all your tires in rotation makes them last longer
because
the tires on the road are usually better maintained than a spare sitting in
a spare
holder for 5-10 years.
bob

On Mon, Sep 13, 2010 at 7:48 PM, Michael A. Radtke <wa7zpu@cisaz.com> wrote:

> Hello,
>
> I was filling and checking my tires today and I was surprised to find
> the spare flat.
>
> My spare is at least 10 years old, and is in excellent shape since it
> has been off the road and out of the UV all this time.  It became a
> spare as a lightly used tire and I've never needed it.  When I did a
> quick check for what could be leaking, I found that the bead to steel
> rim seal was leaking in a lot of spots.
>
> So, what caused this problem?  All the leaks are on the side that was
> up.  My first thought was rust, but I live in Phoenix and we get little
> rain.  Besides, the rim doesn't look rusty.  Do other Vanagon owners see
> the same problem with old spares?
>
> How do I fix the tire?  I am uncomfortable with just remounting it if I
> don't know what the cause was.  I could put a radial tube in it.  This
> is a spare.  I just need it to work in an emergency for a relatively
> short distance.
>
> Information and advice please?
>
> Thanks,
> Mike   '84 GL since new --- Phoenix, AZ
>