Missing Piece Checker: 42123 McLaren Senna GTR

Checking

42123 McLaren Senna GTR

830 pieces in 131 part and color combinations.

Before you call it missing

Builders who report a missing piece often find it in one of these places. Tick each one off as you look.

Every bag and the box. Shake out each bag, check its corners and seams, and look inside the empty box.
Inside what you have built. Small pieces lodge inside tubes, under plates and between studs. Turn the model over and look.
The last few steps. Compare each recent step with its parts callout. A piece used in the wrong place earlier leaves you one short later.
Look-alike colors. 1 part in this set come in two colors that are easy to mix up; they are listed below.
The spare pieces. This set comes with 14 spare pieces, marked on each row of the checklist. One may be the piece you need.
The floor and your building area. Check under furniture, the chair and the edges of your building surface.

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 Beam 1 x 3 Thick Black ×11 Dark Bluish Gray ×2 Black is darker than Dark Bluish Gray.

Piece checklist

Technic Pins 298 pieces

Technic Pin with Friction Ridges Lengthwise and Center Slots Black Part 2780 Element 4121715 or 278026 1 spare in the box ×146
Technic Axle Pin with Friction Ridges Lengthwise Blue Part 43093 Element 4309323 or 4206482 ×17
Technic Pin 1/2 without Friction Ridges Blue Part 4274 Element 4143005 1 spare in the box ×30
Technic Pin Long with Friction Ridges Lengthwise, 1 Center Slot Blue Part 42924 Element 6299413 ×68
Technic Axle Pin 3L with Friction Ridges Lengthwise and 1L Axle Dark Bluish Gray Part 11214 Element 6015356 ×20
Technic Pin Long with Friction Ridges Lengthwise and Stop Bush [3 Lateral Holes, Big Pin Hole] Light Bluish Gray Part 32054 Element 4211865 ×7
Technic Pin without Friction Ridges Lengthwise Light Bluish Gray Part 3673 Element 4211807 or 3673194 1 spare in the box ×6
Technic Pin 3/4 Tan Part 32002 Element 6663097 or 6013938 1 spare in the box ×2
Technic Pin Long without Friction Ridges, with Anti-Roll Notch Tan Part 39888 Element 6321305 ×2

Technic Bushes 31 pieces

Technic Bush Light Bluish Gray Part 3713 Element 6275844 or 6271817 1 spare in the box ×13
Technic Bush 1/2 Smooth with Axle Hole Semi-Reduced Light Bluish Gray Part 32123b Element 6271165 or 4211573 1 spare in the box ×10
Technic Bush 1/2 Smooth with Axle Hole Semi-Reduced Yellow Part 32123b Element 6271167 or 3212324 1 spare in the box ×8

Plates 16 pieces

Plate 1 x 1 Black Part 3024 Element 302426 1 spare in the box ×6
Plate 1 x 4 Black Part 3710 Element 371026 ×2
Plate 1 x 8 Black Part 3460 Element 346026 ×2
Plate 2 x 8 Black Part 3034 Element 303426 ×1
Plate 1 x 1 Light Bluish Gray Part 3024 Element 4211399 1 spare in the box ×2
Plate 1 x 6 Light Bluish Gray Part 3666 Element 4211438 ×1
Plate 1 x 1 Trans-Clear Part 3024 Element 6513962 or 6252041 1 spare in the box ×2

Bricks Curved 10 pieces

Brick Curved 2 x 1 No Studs [1/2 Bow] Black Part 11477 Element 6047276 ×6
Brick Curved 4 x 1 No Studs [Stud Holder with Symmetric Ridges] Black Part 11153 Element 6580394 or 6037746 ×1
Brick Curved 2 x 1 No Studs [1/2 Bow] Light Bluish Gray Part 11477 Element 6028813 ×2
Brick Curved 2 x 4 x 2/3 No Studs, with Bottom Tubes Light Bluish Gray Part 88930 Element 4597901 or 4544040 ×1

Panels 8 pieces

Panel 1 x 2 x 1 [Rounded Corners] Black Part 4865b Element 6146220 ×8

Wheels and Tyres 8 pieces

Tyre 43.2 x 14 Black Part 30699 Element 6518575 or 6182551 ×2
Tyre 43.2 x 22 ZR Black Part 44309 Element 4184286 ×2
Wheel 30 x 14 Black Part 56904 Element 6251174 ×2
Wheel 30.4 x 20 without Pinholes, with Reinforced Rim Black Part 56145 Element 4299389 or 4284946 ×2

Technic Gears 7 pieces

Technic Gear 12 Tooth Double Bevel Black Part 32270 Element 4177431 ×2
Technic Gear Rack 1 x 7 with Axle and Pin Holes Black Part 87761 Element 6327430 or 4562009 ×1
Technic Gear 12 Tooth Bevel Tan Part 6589 Element 4565452 or 4514556 ×4

Tubes and Hoses 6 pieces

Axle Hose, Soft 16L Black Part 32202 Element 6057525 or 4121649 ×2
Hose Rigid 3mm D. 9L / 7.2cm Black Part 75c09 Element 6409912 or 4614226 ×1
Axle Hose, Soft 11L Blue Part 32199 Element 6331027 or 3219923 ×3

Tiles 5 pieces

Tile 1 x 1 with Groove Black Part 3070b Element 307026 1 spare in the box ×1
Tile 1 x 6 with Groove Black Part 6636 Element 663626 ×2
Tile 2 x 3 Black Part 26603 Element 6162892 ×2

Bars, Ladders and Fences 4 pieces

Bar 4L (Lightsaber Blade / Wand) Trans-Red Part 30374 Element 6507880 or 6167284 ×2
Bar 4L (Lightsaber Blade / Wand) White Part 30374 Element 6116602 or 4129836 ×2

Bricks Sloped 4 pieces

Brick Sloped 30° 1 x 1 x 2/3 (Cheese Slope) Trans-Clear Part 54200 Element 6245250 or 4244362 1 spare in the box ×4

Plates Special 3 pieces

Plate Special 1 x 2 with Pin Hole Underneath Black Part 18677 Element 6192309 or 6167497 ×3

Technic Bricks 2 pieces

Technic Brick 1 x 1 with Pin Hole Black Part 6541 Element 654126 ×2

Technic Special 2 pieces

Technic Tooth 1 x 3 with Axle Hole [Hollow Underside] Blue Part 48267 Element 6597518 or 6336385 ×2

Stickers 1 piece

Sticker Sheet for Set 42123-1 [No Color/Any Color] Part 72203 Element 6323435 ×1

Technic Steering, Suspension and Engine 1 piece

Technic Steering Wheel Small (3 Studs Diameter) Black Part 2819 Element 4580509 or 4160709 ×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.

Request a replacement from LEGO

Buy the piece

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.

LEGO Missing Piece Checker

42123 McLaren Senna GTR

Before you call it missing

Look-alike colors in this set

Your missing list