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.
Builders who report a missing piece often find it in one of these places. Tick each one off as you look.
Look-alike colors in this set
These parts appear in this set in two colors that are easy to confuse. If you are one short in one color,
check whether it went in where the other color belongs. Each color has its own element ID in the parts list
at the back of the instructions.
Tile Round 1 x 1White ×2Trans-Clear ×4Trans-Clear is see-through: hold the piece up to a light.
Technic Axle and Pin Connector Angled #3 - 157.5°Medium AzurePart 32016Element 6261392 or 6133917×6
Technic Beam 1 x 13 ThickMedium AzurePart 41239Element 6261643 or 6133901×3
Technic Beam 1 x 7 ThickMedium AzurePart 32524Element 6261638 or 6133891×4
Technic Panel Curved 11 x 3 with 10 Pin Holes through Panel SurfaceMedium AzurePart 11954Element 6133928×3
Technic Panel Fairing #21 5L Small Smooth, Side BMedium AzurePart 11946Element 6134349×1
Technic Panel Fairing #22 5L Small Smooth, Side AMedium AzurePart 11947Element 6134350×1
Yellow
13 pieces
Technic Axle 7YellowPart 44294Element 6130009×3
Technic Engine CrankshaftYellowPart 2853Element 6640378 or 4119474×2
Technic Engine Piston RoundYellowPart 2851Element 4112203 or 285124×8
Flat Silver
9 pieces
Hose, Ribbed 7mm D. 6L / 4.8cmFlat SilverPart 78c06Element 4620076×8
Tile Round 1 x 1 with Gauge and Red Pointer PrintFlat SilverPart 98138pr0012Element 6287877 or 60303331 spare in the box×1
Tan
9 pieces
Technic Axle Pin without Friction Ridges LengthwiseTanPart 3749Element 4666579 or 4186017×2
Technic Engine Crankshaft CenterTanPart 2854Element 6355727 or 6013937×3
Technic Gear 12 Tooth BevelTanPart 6589Element 4565452 or 4514556×3
Technic Gear 20 Tooth BevelTanPart 32198Element 6031962 or 4514557×1
Trans-Clear
4 pieces
Tile Round 1 x 1Trans-ClearPart 98138Element 6514191 or 62747381 spare in the boxAlso in White×4
White
4 pieces
Technic Pin Connector Round [Slotted]WhitePart 62462Element 6550164 or 6173116×2
Tile Round 1 x 1WhitePart 98138Element 6564903 or 62845721 spare in the boxAlso in Trans-Clear×2
Dark Tan
3 pieces
Technic Axle 5 with StopDark TanPart 15462Element 6055631×3
Reddish Brown
2 pieces
Technic Axle 3 with StopReddish BrownPart 24316Element 6135494×2
[No Color/Any Color]
1 piece
Sticker Sheet for Set 42050-1[No Color/Any Color]Part 25032Element 6136657×1
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.