WG G.Cherokee seatbelts locking

[crunch]

Hey guys,

The rear seatbelts in my old man's Grand lock up, almost all the time. When you get in and try and put your belt on, and in transit.

He's had it to Jeep numerous time with the typical answer of 'we can't find anything wrong'. There is very obviously something wrong though, as the seat belts become almost unusable, you have to play around with them for ages until they work, and even then, they still lock in transit. Both sides do it, and (as far as i know) only the rears.

Is this a common problem? Have any of you heard about it or experienced it before?

To me it seems like the roll isn't going back far enough, (as if the belt is too short) and the lock mechanism isn't disengaging properly. But again, they still lock in transit anyway..

Thanks in advanced.

Andrew.