What was Expert Builder?

It was the original name of the mechanical building range launched in 1977, which later became Technic.

How many pieces does the 1977 Tractor contain?

It has 324 pieces in 67 different part types, with no minifigures.

Are the parts compatible with modern Technic?

Axles and gears generally fit later Technic parts. The older light grey is the main visible difference.

Expert Builder

Tractor

Few Technic-style sets are older than this one. The 851 Tractor appeared in 1977 under the Expert Builder banner and brings together 324 pieces in red, grey, black and yellow.

Set number: 851
Year: 1977
Pieces: 324
Minifigures: 0
Theme: Expert Builder
Different parts: 67

What can I build with it?

Parts list 67

As BrickLink list (XML)

Import on BrickLink: Wanted → Upload, upload the file (or paste its content), pick a Wanted List and add the parts.

Description

Expert Builder, 1977

Expert Builder was the name LEGO® gave to its first range of mechanical building sets, launched in 1977. It introduced bricks with holes, axles, gears and connectors so that models could show how real machines work. The range later grew into Technic, the name still used today. The 851 Tractor belongs to that first generation, which makes it interesting not just as a model but as a record of where the whole system started and which parts it was built on.

A small parts vocabulary

The set contains 324 pieces but only 67 different part types, and there are no minifigures. That relatively short list tells you a lot about 1977: many of the specialised elements later builders take for granted did not exist yet. Designers worked with bricks, plates, axles, bushes and a handful of gears, and got remarkable results from them. Building 851 today is a lesson in how much can be done with a limited toolkit and a bit of ingenuity.

Red, grey, black, yellow

The catalogue lists red, light grey, black and yellow as the main colours. Red and yellow are the bold colours in that list, with grey and black in a supporting role. Having only 67 part types across four main colours keeps sorting simple. The light grey is the older shade that disappeared around 2004, so these parts sit slightly apart from modern grey elements when you mix them. For collectors, the combination is instantly recognisable as late-seventies mechanical building, and it looks quite different from the grey-and-black sets that followed decades later.

Owning a piece of history

If you have inherited or found a copy of 851, the parts list on this page helps you check how complete it is, piece by piece. Missing elements can then be sourced individually rather than guessing. Many early axles and gears remain compatible with later Technic parts, so the set can also serve as a starting point for new ideas. The “What can I build?” tool compares your inventory with other sets and suggests what else you could build from it.

FAQ

What was Expert Builder?: It was the original name of the mechanical building range launched in 1977, which later became Technic.
How many pieces does the 1977 Tractor contain?: It has 324 pieces in 67 different part types, with no minifigures.
Are the parts compatible with modern Technic?: Axles and gears generally fit later Technic parts. The older light grey is the main visible difference.