You may be mixing up info for other model vans than yours.  The 86+ with
Girling calipers use 2 small M8 bolts with 13mm heads to hold each
caliper to the carrier guide pins. Those are supposed to only be used
once. If you get new pin bolts from an auto parts supplier they should
come with thread locking compound already on them.

The main caliper bolts on 80-85 vans are 19mm head and use less torque
than 86+ with larger caliper bolts and 22mm heads. Either way, the main
bolts can be reused.

Mark