>| I hear a sharp, metallic knock from somewhere under the front seats, or maybe a little further back, when I go over a bump. Like someone is hitting the chassis with a small hammer.
>| Any suggestions?

        I had something that sounded similar to what you describe on my 87
syncro. It was caused by the passenger side brake caliper not sliding
smoothly on its guide bolts (on release of the brakes on side would not
back off completely and the caliper would jiggle when I went over bumps). I
found this by just wiggling the caliper one day. The reason the caliper was
binding was that the lower guide bolt had a slight layer of corrosin on it
due most likely to a slight tear in the protecting boot. I removed the
bolt (or pin - it doesn't have any threads on it), lightly sanded off the
corrosoin with emory paper, lightly greased the pin with MSO2 grease and
resembled. The dealer near me didn't know what these bolts were so I didn't
replace the torn one (hopefully the grease will keep the corrosion out for
a while). The Bentley calls these things the guide bolts, but if memory
serves, they are what the caliper housing (on the later model calipers) attach
to and will just pull out once the caliper is detached from the bit that
joins the upper and lower control arms (sorry, I cannot remember the name)...

dave