The Caterpillar 231D hydraulic excavator was introduced in 1989 in the USA. Production began in Belgium in 1991.

[edit] Features

The 231D has a 3208 turbocharged engine producing 200 flywheel horsepower (FWHP). It has an operating weight of 77,880 to 83,600 pounds (35,400 to 38,000 kg). It comes standard with a redesigned upper frame, two new sticks, and increased hydraulic horsepower and drawbar pull.

The 231D was manufactured in the USA, with a 1NK serial number prefix, and in Belgium, with a 5WJ prefix.

The 1NK also has a counterweight increase of 23 percent, a new one-piece boom, two-piece travel, and fuel tank capacity of 106 gallons (400 L).

The 5WJ has a counterweight increase of 19 percent, new general purpose and mass excavation booms, and increased trenching productivity.

[edit] Modifications

In 1992 Caterpillar replaced the air compressor boost of hydraulic tank pressure with an engine turbo boost, beginning with 1NK00302.

Production of 231D ended in 1993.

Based on data from the sales database of Ritchie Bros. Auctioneers, it is estimated that more than 600 Caterpillar 231D hydraulic excavators have been produced.

Highest Serial #

Belgium
5WJ	00328
USA
1NK	00320
Total = '648'