Repair or swap safety devices?

[Dogs Danglies]

These are inertia seat belts I presume? i.e. standard ones, whats wrong with them, are they locking up stopping you from getting any slack out of them, or are they not locking if you pull hard on them, like they should.

If its not feeding out any slack you might find loosening the bolt and making sure they pointing pefectly vertical, as sometimes the little ball bearings inside dont like being off vertical, if its anything else just get new ones, or good ones of a car down the breakers, most seatbelts from other cars will fit