is it possible to remove the passive shoulder seat belt and install the side mount one? I am not sure the Jag dealer here will fix my passive belt
Yes, i did it on my 88 with passive belts.
But it involves getting several used parts from mid 80s XJSs:
three point belts/retractors with all the hardware
normal headliner trim piece
bezels for slots needed to be cut in rear quarter panel trims
can’t recall, but new B pillar trim may be needed?
You’ll need to remove rear quarter panel trims to remove old system, and install retractor.
You’ll also want to remove seats, so you can remove bulky retractor for passive system attached to the seat.