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.
Technic Panel Fairing #7 3L Very Small Smooth, Side ABlack ×4Trans-Brown ×1Trans-Brown is see-through: hold the piece up to a light.
Technic Panel Fairing #8 3L Very Small Smooth, Side BBlack ×4Trans-Brown ×1Trans-Brown is see-through: hold the piece up to a light.
Technic Axle and Pin Connector Angled #3 - 157.5°Black ×9Dark Bluish Gray ×1Black is darker than Dark Bluish Gray.
Technic Beam 1 x 13 ThickBlack ×4Dark Bluish Gray ×2Black is darker than Dark Bluish Gray.
Technic Beam 1 x 7 Thick with Alternating HolesBlack ×1Dark Bluish Gray ×4Black is darker than Dark Bluish Gray.
Technic Panel Curved 5 x 7 Parallelogram LeftBlack ×1Dark Bluish Gray ×1Black is darker than Dark Bluish Gray.
6 more look-alike pairs
Technic Panel Curved 5 x 7 Parallelogram RightBlack ×1Dark Bluish Gray ×1Black is darker than Dark Bluish Gray.
Technic Panel Triangle 5 x 4 LeftBlack ×1Dark Bluish Gray ×1Black is darker than Dark Bluish Gray.
Technic Panel Triangle 5 x 4 RightBlack ×1Dark Bluish Gray ×1Black is darker than Dark Bluish Gray.
Technic Pin Connector Hub with 1 AxleBlack ×9Dark Bluish Gray ×2Black is darker than Dark Bluish Gray.
Technic Pin Connector Hub with 1 Pin with Friction Ridges Lengthwise [Centered Friction Ridge]Black ×15Dark Bluish Gray ×2Black is darker than Dark Bluish Gray.
Technic Pin Connector Round 1L [Beam]Black ×7Dark Bluish Gray ×10Black is darker than Dark Bluish Gray.
Technic Axle and Pin Connector Perpendicular SplitBlackPart 92907Element 6279021 or 4610371×2
Technic Axle and Pin Connector Perpendicular TripleBlackPart 63869Element 6362991 or 6007966×7
Technic Ball Joint with Through Axle HoleBlackPart 53585Element 4286267×1
Technic Beam 1 x 11 Thick with Alternating HolesBlackPart 73507Element 6330585×4
Technic Beam 1 x 11.5 Double Bent ThickBlackPart 32009Element 6271152 or 4111998×2
Technic Beam 1 x 13 ThickBlackPart 41239Element 4522933 or 4164422Also in Dark Bluish Gray×4
Technic Beam 1 x 15 ThickBlackPart 32278Element 4542573 or 4128603×2
Technic Beam 1 x 15 Thick with Alternating HolesBlackPart 71710Element 6321716×2
Technic Beam 1 x 2 Thick with Pin Hole and Axle HoleBlackPart 60483Element 6265091 or 6006140×6
Technic Beam 1 x 2 ThinBlackPart 41677Element 6338428 or 4167726×18
Technic Beam 1 x 3 ThickBlackPart 32523Element 4142822 or 3252326×12
Technic Beam 1 x 3 ThinBlackPart 6632Element 6331723 or 4107828×6
Technic Beam 1 x 4 ThinBlackPart 32449Element 6327548 or 4142236×2
Technic Beam 1 x 5 ThickBlackPart 32316Element 4142135 or 4140429×8
Technic Beam 1 x 5 Thin with Axle Holes on EndsBlackPart 11478Element 6327028 or 6030286×2
Technic Beam 1 x 7 ThickBlackPart 32524Element 4495935 or 4155458×4
Technic Beam 1 x 7 Thick with Alternating HolesBlackPart 2391Element 6435016Also in Dark Bluish Gray×1
Technic Beam 1 x 7 ThinBlackPart 32065Element 6271573 or 6253293×1
Technic Beam 1 x 9 Bent (6 - 4) ThickBlackPart 6629Element 6279881 or 4119800×6
Technic Beam 1 x 9 ThickBlackPart 40490Element 4645732 or 4542788×2
Technic Beam 2 x 3 L-Shape with Quarter Ellipse ThickBlackPart 71708Element 6326047×14
Technic Beam 2 x 4 L-Shape ThickBlackPart 32140Element 6271825 or 4120017×14
Technic Beam 2 x 5 L-Shape with Quarter Ellipse ThickBlackPart 80286Element 6407066 or 6378466×4
Technic Beam 3 x 5 L-Shape ThickBlackPart 32526Element 4142823 or 3252626×7
Technic Beam 3 x 5 L-Shape Thick with Alternating HolesBlackPart 2477Element 6408182×4
Technic Beam Frame 5 x 7 with 3 x 5 Opening ThickBlackPart 64179Element 6016154×4
Technic Beam Frame 7 x 11BlackPart 39794Element 6265643×1
Technic Brick 1 x 2 with Axle Hole Type 1 [+ Opening] and Bottom PinBlackPart 32064aElement 6178922 or 4233487×1
Technic BushBlackPart 3713Element 6332148 or 62105061 spare in the box×1
Technic Driving Ring Connector Smooth [2 rounded and 2 flat side walls]BlackPart 42195Element 6286381×3
Technic Gear Rack 1 x 13 with Axle and Pin HolesBlackPart 64781Element 6302830 or 4540906×1
Technic Link 1 x 9BlackPart 32293Element 6244698 or 4141300×1
Technic Panel 5 x 11 x 1BlackPart 64782Element 4566243×2
Technic Panel Curved 5 x 7 Parallelogram LeftBlackPart 80267Element 6380021Also in Dark Bluish Gray×1
Technic Panel Curved 5 x 7 Parallelogram RightBlackPart 80268Element 6380030Also in Dark Bluish Gray×1
Technic Panel Fairing # 3 Small Smooth Long, Side ABlackPart 64683Element 4541924×2
Technic Panel Fairing # 4 Small Smooth Long, Side BBlackPart 64391Element 4541325×2
Technic Panel Fairing #10 Medium Triangle SmoothBlackPart 2403Element 6510087 or 6426604×3
Technic Panel Fairing #21 5L Small Smooth, Side BBlackPart 11946Element 6316923 or 6023036×6
Technic Panel Fairing #22 5L Small Smooth, Side ABlackPart 11947Element 6319983 or 6022761×6
Technic Panel Fairing #7 3L Very Small Smooth, Side ABlackPart 2387Element 6510991 or 6426589Also in Trans-Brown×4
Technic Panel Fairing #8 3L Very Small Smooth, Side BBlackPart 2389Element 6513874 or 6426590Also in Trans-Brown×4
Technic Panel Fairing #9 Medium Triangle SmoothBlackPart 2395Element 6510081 or 6426603×3
Technic Panel Fairing 2 x 1 x 1BlackPart 89679Element 6396456×2
Technic Panel Triangle 5 x 4 LeftBlackPart 80278Element 6400130Also in Dark Bluish Gray×1
Technic Panel Triangle 5 x 4 RightBlackPart 80274Element 6400129Also in Dark Bluish Gray×1
Technic Pin Connector Hub with 1 AxleBlackPart 22961Element 6253260Also in Dark Bluish Gray×9
Technic Pin Connector Hub with 1 Pin with Friction Ridges Lengthwise [Centered Friction Ridge]BlackPart 65487Element 6282140Also in Dark Bluish Gray×15
Technic Pin Connector Hub with 2 Perpendicular AxlesBlackPart 10197Element 6099801 or 6098801×9
Technic Pin Connector Perpendicular 2 x 2 BentBlackPart 44809Element 6325982 or 4480926×8
Technic Pin Connector Round 1L [Beam]BlackPart 18654Element 61214851 spare in the boxAlso in Dark Bluish Gray×7
Technic Axle and Pin Connector Perpendicular 3L with Centre Pin HoleWhitePart 32184Element 6276981 or 6114940×2
Technic Brick 1 x 1 with Axle HoleWhitePart 73230Element 6345886×2
Orange
7 pieces
Gear Shifter ForkOrangePart 4159Element 6447082×2
Technic Beam 1 x 2 Thick with Pin Hole and Axle HoleOrangePart 60483Element 6265128 or 6057526×3
Technic Tread AttachmentOrangePart 24375Element 61855511 spare in the box×2
Trans-Red
6 pieces
Brick Sloped 30° 1 x 1 x 2/3 (Cheese Slope)Trans-RedPart 54200Element 6245252 or 42443631 spare in the box×3
Plate 1 x 1Trans-RedPart 3024Element 6513963 or 62520421 spare in the box×1
Tile Round 1 x 1Trans-RedPart 98138Element 6514189 or 62586071 spare in the box×2
Trans-Clear
4 pieces
Minifig Head [Plain] [Vented Stud - 2 Holes]Trans-ClearPart 28621Element 6513992 or 6168665×2
Tile Round 1 x 1Trans-ClearPart 98138Element 6514191 or 62747381 spare in the box×2
Flat Silver
3 pieces
Zipline, 22L with 2 Connectors - FlexibleFlat SilverPart 27965Element 62105901 spare in the box×3
Green
3 pieces
Technic Gear 20 Tooth with Clutch on Both SidesGreenPart 81346Element 6391159×3
Dark Tan
2 pieces
Technic Axle 3 with StudDark TanPart 6587Element 6031821 or 6013821×2
Medium Azure
2 pieces
Gear Shifter with Groove, 8 Steps, Letter MarkingsMedium AzurePart 4158Element 6447081×2
Metallic Silver
2 pieces
Tile 1 x 2 with GrooveMetallic SilverPart 3069bElement 6546112 or 6217492×2
Pearl Titanium
2 pieces
Technic Axle Connector 2 x 3 QuadruplePearl TitaniumPart 11272Element 6251539 or 6022718×2
Trans-Brown
2 pieces
Technic Panel Fairing #7 3L Very Small Smooth, Side ATrans-BrownPart 2387Element 6510992 or 6426591Also in Black×1
Technic Panel Fairing #8 3L Very Small Smooth, Side BTrans-BrownPart 2389Element 6513875 or 6426593Also in Black×1
Trans-Orange
2 pieces
Tile Round 1 x 1Trans-OrangePart 98138Element 6514197 or 62747471 spare in the box×2
[No Color/Any Color]
1 piece
Sticker Sheet for Set 42159-1[No Color/Any Color]Part 10101061Element 6415926×1
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.