The Euclid S-7 revisited

Smallest of all of Euclid’s motor scrapers, the S-7 had an appetite for dirt nonetheless and was a good performer, serving its owners well. By RICHARD CAMPBELL.

We first had a look at the Euclid S-7 back in the March 2005 issue of Contractor. In those days I didn’t have much column space and so was limited to the material I could present. Since that article was written I have uncovered more information on the little S-7 which was a popular scraper in New Zealand. Designed from the outset as a utility machine for large or small contractors, the Euclid S-7 was introduced in 1954. Powered by a General Motors 4-71 diesel rated at 138 horsepower and sporting a Fuller 5-speed manual transmission, the nippy little machine held seven cubic yards struck and nine cubic yards heaped and was known as the 3UOT-26SH series. The machine was a success from the outset, and at the time of its introduction, it had little in the way of competition other than LeTourneau-Westinghouse’s Model D, which held a similar payload. With its bare bones basic design and all-hydraulic operation, S-7s were preferred by a lot of contractors who couldn’t get to grips with the all-electric LeTourneau D.

Spurred on by the success of the 3UOT S-7, Euclid introduced an improved version in 1956 known as the 4UOT-26SH series. This retained the GM 4-71 powerplant which had a power increase up to 143 horsepower, but was fitted with a 4-speed Allison powershift transmission making the unit extremely user-friendly for novice operators. Both the 3UOT and 4UOT were built at GM Euclid’s Hudson, Ohio manufacturing plant.

Euclid had also established a manufacturing facility in the UK in Scotland which began producing S-7s in mid-1955 which were called B3UOT-B3SHs. The UK-built S-7s differed from their American cousins by having Leyland AU600 engines rated at 147 horsepower and a Simms or CAV electrical system. Bowl capacity was the same as the US version and the UK machines also retained the 5CB Fuller manual transmission.

As an indication of how well GM/Euclid had ‘got it right’ first time, S-7 open bowl scrapers were manufactured virtually unchanged during the entire 17-year production life of the machine.

There were some small modifications however as the US-manufactured machines received a horsepower increase in 1961 to 148 flywheel horsepower and a newer version of the Allison CLT 3341 powershift transmission.

It was around this time that the tractor unit panelwork was revised and the machine lost its two prominent front headlights, these being replaced by modular units mounted on the bumper but Euclid US did not change the serial number series to reflect these modifications.

Alterations were also made to UK-produced S-7s. These were a little more drastic and involved replacement of the Leyland engine with a 148 horsepower GM 4-71, installation of the powershift Allison CLT3341 transmission, and a similar remodeling of the tractor unit’s panel work
In this form, the ‘new’ S-7 was known as the B8UOT-B3SH series. The S-7 continued in production in the UK for three years after the type had been discontinued in the US.


For the first two years of S-7 production, the machines left the assembly line painted a dark ‘Armington Green’ (Euclid Road Machinery’s original paint scheme). From 1956 until 1967 they were painted GM ‘Hi-Lite Green’ and from 1968 until they were discontinued in 1972, ‘Terex Green’.


The standard S-7 was a very basic machine but there were a few extras that could be added to it ex factory. These included a cab, cab heater, windscreen wiper and an air suspension seat, as the standard machine came with a seat mounted on a circular pedestal. There was also the option of fitting larger 21×25 16-ply E3 tyres.

The competition

Contemporaries of the Euclid S-7 included the aforementioned LeTourneau-Westinghouse Model D, the Allis-Chalmers TS160, Michigan 110 and Curtiss-Wright CW-28. Caterpillar did not offer any comparable sized machine to the S-7.

Variations on a theme

The S-7 tractor unit proved to be a good basis for mounting other forms of earthmoving equipment. There were several different variants offered over the years and these are described as follows:

S-7 with Easton-designed rock dumper (USA)

First marketed in 1956, the 3UOT-129W series rock dumper was designed to compete with the LeTourneau-Westinghouse D Tournarocker but only had a limited production run and very few were manufactured. L-W had this segment of the market well sewn up.

S-7 with Euclid-designed rock dumper (UK)

Based on the B3UOT tractor and very similar to the US assembled model, this too shared the same fate as its American cousin.

S-7 with Athey rock dumper (US)

Another short-lived attempt to break into the small rock dumper market, the Athey rear dumper was extremely rugged and well built. Introduced in 1966, the sales just weren’t there and the type was withdrawn by 1968.

S-7 with Hancock 12E2 elevating scraper (US)

Following a couple of trial prototypes, the S-7 Hancock made it into production in 1965. Designed to capture some of Le-Tourneau-Westinghouse’s and John Deere’s market share, this time in the elevating scraper category, the S-7 Hancock was partially successful. With a capacity of 12 cubic yards, the machine was unusual in that it had a separate GM 2-71 engine mounted on the rear of the scraper solely to power the 17 flight elevator unit via a drive shaft and reduction gearbox.

The last variation of the S-7 line came along in 1968 and was also another elevating scraper, the S-12E. 

This was basically an S-7 Hancock on steroids and also featured a 12 cubic yard capacity bowl with the elevator powered by a separate GM 2-71 engine plus other features added as a result of experience with the S-7 Hancock. This was all just a bit much for the little S-7 to handle and the GM 2-71 engine on the back which only ran the elevator, provided no added tractive effort at all. All these factors made the S-12E quite sluggish in operation and very few were manufactured. Euclid/Terex eventually did produce an acceptable small elevating scraper, the S-11E, but it was mostly designed and manufactured by Clark!

The New Zealand connection

Clyde Engineering,  NZ distributor for Euclid (and later Terex), imported a total of 23 Euclid S-7s – 10 American 4UOTs, 10 UK B3UOTs and three UK B8UOTs spanning the years 1956 to 1972

Euclid S-7s have seen service all over New Zealand and most have had many owners.

Particular mention should be made of Te Pohue Contractors and Beattie Bros, both from the Hawke’s Bay, which kept well maintained examples well into the 1970s. It is unusual to find a complete running S-7 these days, but they do exist. Its scrapers however, have found a new lease of life as towed scoops. No S-7 Hancock or S-12E elevating scrapers were ever imported, the type just being a little too unusual for New Zealand earthmovers.

For the model collector

Siku model of Euclid S-7

Very slim pickings I’m afraid as there has only ever been one model produced of the Euclid S-7, and unfortunately, not the scraper version. This was manufactured to 1:50 scale by German diecast producer Siku in the 1960s and represents an S-7 with an Athey rear rock dumper. Long out of production, they are not too hard to find on Ebay and fetch between $80 to $120 depending on condition. They aren’t too bad as a model but are certainly a product of their time. Be warned that they were never painted Euclid ‘Hi-Lite Green’ and come in a circus of colours so be prepared for a repaint if you really want an accurate example.

Brief Specifications – Euclid S-7 Scraper model 4UOT-26SH (1958)

Engine:            General Motors 4-71, inline, 4-cylinder two cycle diesel rated at 143 flywheel horsepower at 2100 rpm

Transmission: Allison CT3340, 4-speed full powershift transmission

Top speed:      25 mph

Brakes:            Air operated shoe type on both axles

Steering:          Full hydraulic, 90° to each side

Turn circle:      28′

Tyres:             18×25, 16 ply, E3

Capacity:        7 cubic yards struck, 9 cubic yards heaped

Operation:       Fully hydraulic via four interchangeable, single acting hydraulic rams

Length:            29′ 10″

Width:             8′

Height:            8′ 4½”

Op.weight:      13 tons empty, 23.7 tons loaded

Related posts

Euclid’s TS-18 motor scraper

Contrafed PUblishing

The Euclid/Terex S-24 scraper

Contrafed PUblishing

Euclid’s TS-14 scraper

Contrafed PUblishing