Caterpillar D7

Caterpillar D7
	; Caterpillar D7-3T of 1944 Standing outside the George Stevenson hall at Newark VTH show 2008
Model history
Model introduced	Unknown
Model discontinued	Unknown
Model status	Unknown
Fuel type	Diesel
Power hp	Unknown
Cooling system	Water
Transmission Details
Transmission type	Unknown
Drive	tracked
Linkage Category	Unknown
Other info
Factories	USA
Plow rating	Unknown
Web site	http://www.Caterpillar.com
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The Caterpillar D7 is a large track-type tractor designed and manufactured by Caterpillar Inc.

Though it comes in many configurations it is most commonly sold as a bulldozer equipped with a detachable large blade and a rear ripper attachment in recent years. Early versions had Bulldozer gear by 3rd party manufacturers like LeTourneau added that used cable control units before hydraulics became more common after WWII. A lot of tractors were sold for pulling Scrapper boxes and trailed implements. The UK received some of the early models under lend lease during WWII. After the war they were sold off and contractors and farmers bought them. A few examples have started to be saved and are appearing in plant collections and at shows.

History[]

Caterpillar D7E-47A1624 at Belvoir 2010 - IMG 2957 — A Caterpillar D7E-47A at Belvoir Castle Steam Festival 2010 (blade removed for transport)

1935: Caterpillar RD7 5E series introduced, as upgrade to the Caterpillar Diesel Fifty
1935; Caterpillar RD7 9G series replaces the 5E series.
1938: The "R" prefix dropped, D7 débuts.
1940: D7 7M series starts production
1944: D7 3T series introduced; Deal with LeTourneau ends, and Cat introduces own Bulldozer Blade design.
1955: D7 3T Series ends production with over 28,000 machines produced; 128 hp (95 kW) D7C 17A series introduced with new D339 diesel engine.
1959: D7C ends, 140 hp D7D introduced. (Both retain 17A series reference)
1961: D7D replaced by D7E 48A series. Horse power increased to 160 hp (120 kW)
1969: D7E replaced by D7F of 180 hp (130 kW).
1975: D7F replaced by D7G of 200 hp (150 kW).
1986: D7G replaced by D7H with elevated sprocket design. The D7H was the first D7 with the elevated drive sprocket undercarriage
1996: D7H replaced by D7R

Current D7 Models[]

Model no.	Engine	Power	Weight	Notes
Caterpillar D7R Series 2	Caterpillar 3176C	240 hp (180 kW)	25304 kg

Blades[]

Several types of bulldozer blade can be used on the front of the tractor:

A straight blade ("S-Blade"): A short blade and has no lateral curve, no side wings, and can be used for fine grading
An angle blade: Is held by an U shape frame that has 3 holes on each side, to set the blade to 3 positions: to the right, center, and left.
A universal blade ("U-Blade"): A tall and very curved blade, and has large side wings to carry more material
An "S-U" combination blade: A shorter blade, with less curvature, and smaller side wings

Various other blade types are used including landfill U-Blades, woodchip U-blades, and two-way blades for work inside the holds of ships.

Rippers[]

Several versions available;

Single shank for rock
Multiple shank for general surface loosening

UK Preserved Examples[]

D7 (7M) SN 9103 has been preserved by ACMOC member Paul Tolfield. This machine has a Caterpillar D8800 engine of 80 hp. The machine has a 5F - 4R gearbox with FR shuttle transmission.^[1]
Another D7 is in the Fred Knight collection
The Vintage Excavator Trust site in Cumbria has a D7 with Wide tracks stored there. (the machine looks in a very poor state of repair and the wide tracks are self made)
There may be one in the S.E. Davis & Son Ltd. collection. (A they have every other one from a D2 to a D9 )
D7 3T (4T) from 1944 in the collection of John Walker collection from Retford in Nottinghamshire. (Photo above)
D7E (47A) sn 1624 from 1963 of C. Pitchfork of Kinoulton ? seen at the Rempstone Steam Rally 2010

References[]

↑ CP&M Vol 1 no. 10, June 2003

Giant Earthmovers "An Illustrated History", by Keith Haddock, Published by MBI, ISBN 0-7603-0369-X

External links[]

Caterpillar D-Series Track-Type Tractors - Official Caterpillar website

[1] CP&M Vol 1 no. 10, June 2003

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