Home Machinery Caterpillar 633C Scraper (1969-70)

Caterpillar 633C Scraper (1969-70)

Caterpillar 633C Scraper (1969-70)

Just sitting on the Border Ranges between Qld and NSW one will find some unique farming and cropping operations .. none more interesting and technically advanced than the Sweet Family whom are one of Australia’s leading Strawberry Runners (Plants) suppliers.

Headed up by Wally Sweet and proudly supported by his family, they have continued the dreams of his father who bought the property way back in 1960’s.

Back then it was a sheep farming operation but over the ensuing years the property has been through many changes to where they now supply 1/3rd of Australia’s new Strawberry Runners to the aspiring Strawberry Farmers throughout the land.

Now this type of country, although perfect for strawberries, is far from being ideal as to engage in a little bit of clearing, ploughing and sowing. Located in what is commonly known as the Granite Belt, the area is bound by light to heavy scrub, trees and massive unforgiving numbers of granite rocks.

The family, having a heavy machinery background, were never contemplating sourcing contractors to take a role in clearing and preparing the country for their needs so they continually looked out for suitable used machinery to assist in achieving their end goals.

In an effort to secure an excellent and sustainable water storage facility (or several) the Sweets were in dire needs of several items of earthmoving equipment being Dozers, trucks, excavators, graders, tractors with multiple attachments and of course scrapers.

This brings me to our story on the old 1969/70 Caterpillar 633C Elevating Scraper.


One of the first things you will notice is that the 633C Scraper is quite a large machine when you stand beside it. It runs 33×35 tyres both front and rear, however out here on the farm procurement of used tyres are definitely the go.

At a cost of up to $20k per new Michelin Tyre one would not attempt scrub clearing and risk a stick going through the side wall in one of these, so second hand and well used tyres at that fit the use and hip pocket just nicely !!!

The cubic capacity of the bowl is measured in cubic yards. Determining the size of the Scraper is relevant to the volume of the bowl which in this case is 33 cub yards when filled.

Identification of Caterpillar equipment is always a combination of numbers and letters and in the case of a Scraper one can identify the size, as in this case 633C.

The letter “6” is allocated to Caterpillar Scrapers and “33” is the cubic capacity of the bowl and “C” is the model.

A quick look around the old girl and one can easily see that there is wear and tear at all points of the compass. Not to be deterred as this is not a daily driver, not going to any mine site and definitely not going on contract anywhere in the near or distant future.

The elevator chains are well worn and stretched to the limits as are the 13 hydraulically driven elevator flights now showing signs of welded and plated repairs.

The gooseneck between the prime mover and the bowl has been professionally repaired due to severe cracking. These repairs were done in-house at the farms fully integrated workshop, filled with all the goodies and the skilled labour to fulfil all of the farms mechanical repairs and servicing.

This area in between the bowl and the scraper cabin is a “no-go zone” for personnel when the machine is working.

The beauty of the scraper design is that it can turn on sixpence (5 cents). The operator can squeeze 90 degree rotation to the left and right very quickly with a flick of the wrist on the steering wheel due to the hydraulic ram steer controls. This is perfectly suited for quick turns or to get out of a bog or some sticky positions requiring diff lock assistance. Anyone located in this zone when the scraper is operational will be severely injured or killed.

Sitting at about 44 feet long it could almost turn in its own length with a turning circle of 40 feet.


Now when these machines were built the engine was a state of the art Caterpillar D343 Turbo after cooled engine which went into the production of many of Caterpillar machines and became a very popular favourite amongst Earthmovers.

Pushing out about that 400hp @ 1900 rpm the Cat D343T 6 cylinder engine was connected to the  Caterpillar 8 speed semi-automatic transmission with a top speed of about 32mph.

The 633C Scraper runs in at about 40 tons empty and, dependent upon the material would push up to 70 tons when fully laden.


Once in the cabin, in this case open cab with only an optional extra windscreen sitting between the operator and the elements, you will notice that vision is impaired, restricted or non-existent in some areas of view.

The operator sits on a semi suspension seat located near and above the left wheel with a set of gauges on two panels separated by the steering column.

To the right side of the cabin the operator has very little vision due to the huge exhaust and positioning of the Air Cleaner located out of the dust, up and high, however when it comes to vision to the bowl Cat have got it sorted with the design of the slightly off set seating arrangement giving the operator a great view of the bowl and the discharge of material and feed.

Controls are quite simple once you get the feel of the movement, side-swaying and power of the Cat. Steering wheel central to the seating, foot throttle, brake and diff lock on the floor, 8 speed semi auto transmission at knee height on the right side forward of the seat.

To the right of the seating and at arm pit height were the ejector and elevator control levers. Filling of the bowl with suitable materials could be as quick as 60 seconds for a 33 yard fill .. good in anyones language and this is some 50 years ago.


The old girl may have a few creaks and groans in her these days but it gets the job done and that’s exactly why the Sweets bought her.

Running along the farm access track down to the dam site or borrow pit the mind goes way back to a younger Ronnie and another great era of construction in the 70’s and 80’s when I ran a couple of scrapers  namely Wabco, International, Cat 633c and I actually owned an old Cat 621J open Bowler in another life.

I was never “a gun operator” and had my fair share of close calls but I quickly realised that there were great operators around and I held them in the highest of esteem on the sites .. scraper drivers and D9 and D10 operators were the big guns of the day and one can see why.

Taking into consideration the age, condition and working area of the 633C it is easy to see why they were and still are so popular.

A bit slower on the road, a bit slower through the gears, a bit of slop in the hitch, a bit of wear on the chains, tyres, elevators and a lot of wear on the operator all made for a good afternoon in the sun.

It took a passionate plea for me to get Phil Sweet on the old girl to show us how he does it and in a flash he tidied up all of the mistakes. Phil is so passionate about the old gear and loves the old scraper and his beloved Cat Cable Blade D7 Dozer (Review Pending).

When I asked why he said “because they are reliable and we can still get parts for them … it’s that easy.”


There is nothing around that will compete with the efficiency of a fleet of scrapers working the dirt in bulk handling.

Self-loading of 30 cubic metres in 60 seconds, hauled at a top speed of about 55kph, dumped and spread in the one movement … awesome to watch but  more awesome to be part of.

One thing for sure .. you are going to get dirty and dusty in one of these old girls so if you don’t have a passion for them, cant derive any pleasure from the job and can’t handle the pain associated with the hours of being tossed around day after day after day … well this one is not for you.

HOWEVER … There are blokes out there whom have pioneered their way through the ages and laid the groundworks for the younger generations. Suffering ongoing health issues from dust ingestion, crook backs and necks and those legs that just don’t seem to go where you want them once you hit old age all due to the years of confined seating … well those injuries are all forgotten because they would not have it any other way.

Old Scraper operators are a dying breed .. tough, skilful, cranky (most of ‘em I know are) and ill bet money on it … everyone of them loved their Cat Scrapers .. just like the old 633C I ran today.

Ron Horner



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