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 5 with StopReddish BrownPart 15462Element 6159763×1
Technic Beams
6 pieces
Technic Beam 1 x 3 ThickBlackPart 32523Element 4142822 or 3252326×1
Technic Beam 1 x 2 Thick with Pin Hole and Axle HoleDark TanPart 60483Element 6344864 or 6170313×2
Technic Beam 1 x 2 ThinRedPart 41677Element 6371442 or 4186678×2
Technic Beam 1 x 3 ThinRedPart 6632Element 6364451 or 4107824×1
Wheels and Tyres
6 pieces
Technic Wedge Belt Wheel [aka Pulley]Dark Bluish GrayPart 4185Element 6321744 or 4587275×4
Wheel 31 x 15 Technic, 7 Pin HolesRedPart 60208Element 6132385×2
Bricks Curved
4 pieces
Brick Curved 2 x 2 x 2/3Dark BrownPart 15068Element 6047037×2
Brick Curved 4 x 1 Double, No StudsDark TanPart 93273Element 6167936×2
Technic Bushes
4 pieces
Technic Bush 1/2 Smooth with Axle Hole Semi-ReducedLight Bluish GrayPart 32123bElement 6271165 or 42115731 spare in the box×4
Plates
3 pieces
Plate 1 x 2BlackPart 3023Element 302326×1
Plate 1 x 1Dark TanPart 3024Element 4549436 or 44970841 spare in the box×2
Projectiles / Launchers
3 pieces
Launcher, Brick Special 1 x 4 Spring Shooter with Light Bluish Gray TopDark Bluish GrayPart 15400Element 6324200 or 6048898×1
Projectile, Spring Shooter Ammunition 8L BarTrans-RedPart 15303Element 6287550 or 6054526×2
Technic Beams Special
3 pieces
Technic Beam 1 x 3 with Ball Joint in MiddleDark Bluish GrayPart 98577Element 6001085×1
Technic Beam 3 x 0.5 Liftarm with Boss and Pin Semi-ReducedRedPart 33299bElement 6167937×2
Bricks Sloped
2 pieces
Brick Sloped 18° 2 x 1 x 2/3 with 4 Slots / GrateBlackPart 61409Element 4541191×1
Brick Sloped 30° 1 x 1 x 2/3 (Cheese Slope)BlackPart 54200Element 4504382 or 42871591 spare in the box×1
Hinges, Arms and Turntables
2 pieces
Hinge Cylinder 1 x 2 Locking with 2 Click Fingers and Axle Hole, 9 TeethBlackPart 30553Element 4143372×1
Hinge Plate 1 x 2 Locking with 1 Finger On TopBlackPart 30383Element 6338799 or 4144575×1
Plates Special
2 pieces
Plate Special 1 x 2 with Clips Horizontal [Open O Clips]Dark BrownPart 60470bElement 6167941×2
Pneumatics
2 pieces
Pneumatic Hose Connector with Axle ConnectorDark BrownPart 99021Element 6265670 or 6167942×2
Technic Panels
2 pieces
Technic Panel Fairing #1 Small Smooth Short, Side ARedPart 87080Element 6138745 or 4558872×1
Technic Panel Fairing #2 Small Smooth Short, Side BRedPart 87086Element 6138746 or 4558873×1
Windscreens and Fuselage
2 pieces
Windscreen 3 x 6 x 1 Curved with 2 Circular Stud Holders in BottomRedPart 62360Element 6167935×2
Stickers
1 piece
Sticker Sheet for Set 75525-1[No Color/Any Color]Part 29476Element 6174332×1
Transportation - Sea and Air
1 piece
Technic Cylinder 4 x 4 with Pin Holes and Centre Bar, Closed Sides on BarPearl TitaniumPart 41531Element 6074417×1
Tubes and Hoses
1 piece
Hose, Ribbed 7mm D. 19L / 15.2cmFlat SilverPart 78c19Element 6170251×1
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.