how do you unjam middle rear seat belt vauxhall astra?

It can be caused by the 3 degree tilt mechenisum lock. So the seat must be in the correct upright position (nothing trapped at the back of the seat)
Once in the upright position (remember the lock is very sensitive and will move/lock on vibration). So after no vibraions try to yank and pull the seat belt if this does not work try banging the bach of the seat about a foot from the top below seat belt position to free the lock. Again try to pull the belt after allowing any vibration to stop (be carefull not to vibrate the seat before pulling).

Best of Luck

Mike
June 2009