Annoying Rattle above right rear wheel '87 5ktqa

[Lines Peter]

I'm not sure about the seatbelt location in your car but let me take a
SWAG...
In my '86 4kq I developed an annoying rattle in the rear strut/trunk area
AFTER I installed H&R springs with Bilstein Sport struts.  It only happens
on certain road surfaces like roughened interstate concrete.  After tearing
everything apart multiple times, inside the car, suspension, etc... I had no
solution.  I rode in the backseat with my wife driving trying to pinpoint
the cause.  She tells me: "Put your seatbelt on, there's a cop up there"
(It's illegal in Oregon).  I quickly put the seatbelt on, and voila, no
noise.  So I get home and start examining the seatbelt retractors which are
mounted on the strut towers in the trunk.  In addition to the inertia catch,
there is also a little 3/8" ball bearing sitting in a small saucer shaped
cup.  If you tilt the unit more than about 15 degrees, the ball rolls out,
pushes a lever and the seatbelt catches.  The purpose is obviously for
rollover accidents.  The problem here is that the little ball has to be
loose and rattle for it all to work.  Too bad for me that my new springs
make it rattle most of the time.  I'm the last person to suggest modifying a
safety component of your car, so I won't say what I did, but....
I haven't heard that rattle for a long time.

Peter Lines