Thanks to Shawn and Jake for the resources; hopefully someone has the
parts.  But first I'll give Dennis' procedure a try.

Anyway, the little-know secret in Northern California is to take the turnoff
from hwy 101 to Ferndale, which is  a pretty Victorian town. Look for the
turn-off to Petrolia. Don't worry that it seems like you are turning up an
alleyway; that is what the road is like for a great many miles, most of
which is up as you go over the rainbow mtns. This is a major diversion and
very slow with extremely poor surface and constant switchbacks. I can't say
what it looks like going in because it was 9 PM and so foggy I couldn't see
ten feet in front of the bus, but the trip is really worth it. The coast
looks like Ireland with no trees and rolling green hills and broken
shoreline. Breathtaking. And when you leave the coast, you go through valley
after valley of small farms, cattle and sheep, no traffic and some of the
most lovely pastoral landscape you can imagine. And then you hit the
redwoods :)

Nathaniel