Popping clunk from back end when stopping...

[ORSOPERS]

Anyone have any ideas what might cause pop or clunk from the rear end when
stopping?  It doesn't happen every stop.  If I am very light on the brakes
it wont do it.  The back end of the car has to come up some.  Sometimes the
clunk happens 1/2 a second after letting up on the brake pedal, but usually
it is right when I let up on it.

My first thought was the upper strut mount so I pulled out the back seat
today and checked everything for tightness.  Everything was tight.  If I
jack up the back end of the car and let it down quickly it doesn't pop or
clunk.

I did have a problem with one of the front brake pads once that was sort of
like this.  The anti-rattle clip thingys had gotten smashed and allowed the
pad to move in the caliper a bit.  If you would back up and stop then go
forward, the first time you hit the brakes again it would clunk.  Wouldn't
clunk again until you went in reverse, stopped, went forward again.

I have been driving it around with the back seat out and the noise is more
pronounced (the back seat is a great sound insulator).  I can hear the gas
sloshing around in the tank and thought that maybe it was a loose baffle or
something, but I don't think so.


Thanks for everything!

Rand Soper
'88 80q