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 Knob WheelBlackPart 32072Element 6284188 or 4248204×1
Bars, Ladders and Fences
1 piece
Light Cover 1 x 1 Round with Internal Bar / Bionicle Barraki EyeTrans-RedPart 58176Element 6507867 or 6171762×1
Technic Bushes
1 piece
Technic Bush 1/2 Smooth with Axle Hole Semi-ReducedLight Bluish GrayPart 32123bElement 6271165 or 42115731 spare in the box×1
Wheels and Tyres
1 piece
Technic Wedge Belt Wheel [aka Pulley]Dark Bluish GrayPart 4185Element 6321744 or 4587275×1
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.