seat belts lock up?

[phile@stpaul.gov (Philip J Ethier)]

On my '87 VW Quantum Syncro (Quattro in disguise), the right front seat
belt has been causing trouble lately.  The inertia reel will occasionally
lock up and refuse to release.  It may happen when the car hits a bump, in
which case it generally is uncomfortably tight for the wearer.  Sometimes
it locks on braking and refuses to release.  The failure mode that causes
the most concern is when it will be found to be locked in the retracted
position.  The belt can therefore not be used.  I consider this an
unacceptable safety defect.

There seems to be no pattern to what eventually causes it to release. 

Anybody been there, done that?  How did you fix it?

phil.ethier@stpaul.gov