Rule out the usual hiding places first. If the piece really is gone, check the set piece by piece
and leave with the element ID LEGO asks for, or a link to buy the part.
Technic Axle Connector 2 x 3 with Ball Socket, Open Lower Axle HolesBlackPart 93571Element 4610948×2
Technic Axle Connector with Axle HoleBlackPart 32039Element 4107081 or 3203926×2
Minifig Shields, Weapons, & Tools
2 pieces
Weapon Spike Flexible 3.5LRedPart 64727Element 6270082 or 4616842×2
Projectiles / Launchers
2 pieces
Projectile, Large Figure Weapon, Zamor Sphere / BallBright GreenPart 54821×1
Launcher, Large Figure Weapon, Zamor Sphere Launcher, Bottom with Axle HoleRedPart 98564Element 6021671 or 4652056×1
Technic Pins
1 piece
Technic Pin 1/2 without Friction RidgesLight Bluish GrayPart 4274Element 4274194 or 42114831 spare in the box×1
Tick each piece as you find it, or mark it missing.
When a piece really is missing
Ask LEGO
LEGO takes requests for pieces missing from a new set through its customer service site. The form asks for
the set number and each piece's element ID, the number printed beside the piece in the parts list at the back
of the instructions. This checker lists both.
Mark a piece missing and your list links it to an eBay search for that part, which also covers pieces from
older or second-hand sets.
Keep a record
Copy or download your missing list (the CSV opens in any spreadsheet), or print the whole checklist and tick
pieces off on paper. Your marks stay in this browser, so you can check a big set over several sittings.