Looking around under the front end of my '91 Vanagon GL, I noticed a
very rusted part, evidently part of the brake system, since it has
two steel brake lines connected to it.  This mystery part is mounted
on the right frame rail near the sway bar.  Is this the "pressure
regulator" that I see on a couple of the parts web sites?  The rust
is just falling off it in chunks unusual because there is not really
much rust anywhere else under the front.  Do they normally rust so
badly?

Allan