Mechanical spares worth having
Handy spares are nylon coil sleeves, the short chrome outer shooter spring (it rusts quickly), new 1-1/16" balls to spare the playfield, 3" leg levelers, a ring kit made for the game plus flipper rubbers and a shooter tip.
Systems
Source: Repairing Bally 6803 Pinball Games from 1985 to 1989, Clay Harrell (pinrepair.com)