U.S. Army Caterpillar D7 Bulldozer with LeTourneau Scraper Model LS

Anoyher project that I would love to build is the D7 Caterpillar with the LeTourneau Scraper Model LS. I'm very interested in enginering vehicles and equipment used in WW II. So this combination is a very nice subject because it was widely used. Sadly not much Photo material is available from that period except for the Tankograd no. 6022 about the D7 from Michael Franz. Also a page of Panzerserra Bunker about the D7 but with the angledozer. If someone has additional information that he or she wants to share, that would be greatly appreciated. Please use my contact form and I will answer as soon as possible.

From the 1942 Manual TM 5-3076 describing the D7 Tractor with Angledozer. Item for a next project.


Although I call it the D7 bulldozer it should be mentioned that in fact its the Caterpillar D7 tractor with the LeTourneau Model XD7 Bulldozer attachment. Above is a picture, a bit blurry, that shows a Caterpillar Tractor complete with attachment Dozer blade and the LeTourneau Scraper LS. Not much pictures are available. This one is from the Scraper Manual.

Above two vieuws of the Tractor D7 and below the dozer attachment.

Although a bit blurry, the above picture clearly shows a caterpillar D7 with theLeTourneau Model XD7 Bulldozer attachment and the LeTourneu model LS scraper in tow. Note the Dozer Blade is not attached.

Designed for use behind Caterpillar D6 and D7 Tractors, the LeTourneau Model LS Carryall Scraper was a self-loading, hauling and spreading unit of approximately 11 cubic yards heaped capacity. The Scraper was cable controlled by means of the LeTourneau Power Control Unit on the rear of the tractor. This placed quick, positive control of the Scraper in the hands of the tractor operator.

The Model LS Scraper embodied the same good features found in other LeTourneau Scrapers. Large, low pressure pneumatic tires provide ample flotation. High apron lift permitted loading of large boulders and cleared all material in unloading. The sliding tailgate provided positive ejection of all material. Sheaves and cables were out of the dirt, which gave a longer cable life. Electrically arc welded alloy steel construction gave it maximum strength at a minimum of weight. Like other LeTourneau Scrapers, the Model LS was built to stand up under the toughest of job conditions, and when properly operated and maintained, they should have given an almost unlimited amount of trouble-free operation.

Track-type tractor D7 with armored cab to protect the operator against sniper fire and shell and bomb fragments. This Tractor is towing an 8-cubic-yard scraper LeTourneu Model LS of bolted construction to facilitate disassembly and reassembly when transported by air. Note that here like the earlier picture the Dozer Blade is not attached to the LeTourneau XD7 attachment.

To connect a Scraper to a tractor, it was usually not necessary to thread the cable through the Scraper, because when uncoupled fromhe tractor, the cable was usually disconnected from the Power Control Unit on the rear of the tractor and left threaded through the Scraper. If the cable was not threaded through the Scraper, the cable threading instructions should have been followed. With the cable threaded through the Scraper, the tractor should have been backed up to the Scraper tongue and the hoist cable would be threaded thru the double deck sheave assembly and onto the Power Control Unit right hand cable drum. (Refer to Power Control Unit Manual.) Likewise, the dump cable should have been threaded thru the double deck sheaves and onto the left cable drum. Since the tongue was too heavy to lift by hand, a cable socket was welded to the side of the tongue so that it could be raised mechanically by the Power Control Unit.

  Instructions from the Manual TM 5-1210

To raise the tongue, pull a few
feet of slack in the right cable and
loop it down through the cable
socket on the side of the tongue as
illustrated, and insert the cable wedge
from the bottom side. Tap the wedge
into place. Then raise the tongue so
that the hitch block is even with the
tractor drawbar by engaging the Pow-
er Control Unit right hand clutch.

After the tongue is raised up even
with the tractor drawbar, back the
tractor up, positioning the Scraper
hitch block between the jaws of the
tractor drawbar, and insert the draw-
bar pin. Remove the cable wedge from the
cable socket on the side of the tongue,
and take up slack cable. Keep the
wedge in the tractor tool box or some
safe place where it can be readily found.

The Scraper is controlled by means of the Power Control Unit on
the rear of the tractor. The right control lever (viewed
from Scraper to tractor) controls the raising and lowering of the bowl.
Moving the lever toward the center of the tractor (to the left) engages
the hoist clutch and raises the Scraper bowl. Returning the lever to neutral position applies the brake to the cable drum and holds the bowl in the raised position. Moving the right lever away from the center of the tractor (to the right) releases the brake from the cable drum and allows the bowl to lower. Returning the lever to neutral position applies the brake to the cable drum and holds the bowl at the level to which it was lowered. The left control lever of the Pow-\er Control Unit controls the apron and tailgate. Moving the lever to ward the center of the tractor (to the right) engages the dump clutch and raises the apron. When the apron is raised to its full height, the tailgate is then pulled forward and the tailgate return springs inside the springpipe are compressed. Returning the control lever to neutral position applies the brake to the cable drum and holds the apron and tailgate in the position desired.
Moving the control lever away from the center of the tractor (to the
left) releases the brake from the cable drum, allowing the tailgate return
springs to return the tailgate to its original position at the rear of the
Scraper bowl, and also permits the apron to lower.

Overview of Rear Cale Guides

The Models and Materials needed

In the past years a lot of versions of the D7 and other Tractors with Bulldozer attachments were released bij MiniArt and Mirror Models. Thes both firms produced very fine models that represent the real things in detail. But these models are not for the beginner or faint hearted as the give you some challenges as can be seen in the article of Panzerserra. A few of these perils will be shown in this article also. For the subject at hand only two choices were obvious. The U.S. Military Bulldozer from Mirror Models Kit n. 35851 and the U.S. Army LeTorneau CarryAII LS Scraper from LZ Models Kit no. 35510. At the moment I wrote this project, both models were available.

And ofcourse a driver for the Tractor also from LZ Models Kit no. 35911.


Where to find information

Publications found
on the D7 Tractor and Bulldozer Attachment and the LeTourneau Scraper Model LS

Tankograd no. 6022 - U.S. WW II Caterpillar D7 by Michael Franz

Very good publication on just this subject with action pictures and a lot of extra information on attachments. Very recommended.

TM 5-3065 - Tractor, Crawler, Diesel, 70 to 90-DBHP, Standard, Caterpillar, Model D7 - 1945

TM 5-9282 - Power Control Unit, Cable Operating, Rear Mounted
LeTourneau Model R-7 - 1943

TM 5-1580 - Bulldozer
Tractor-Mounted Cable-Operated
LeTourneau Model XD-7 - 1944

TM 5-1210 - Scraper, Road. Towed Type, Cable Operated, 8 CU. YD.,
Type III, Model LS
R. G. LeTourneau, INC. - 1942

Building The Model


The Final Result