While we see scores of vehicles on this site that will be preserved for the next generation, industrial equipment presentation is sorely lacking. There are a few museums out there that cater to such vehicles. However, it is usually a situation where a wealthy benefactor keeps the doors open due to a total lack of public interest. When that person passes on, the museum is usually finished. That is sad, because equipment like this 1955 Caterpillar D4 bulldozer for sale on Facebook Marketplace in Glenrock, Wyoming has a story to tell. In the postwar boom years, equipment like this built countless roads, flattened out many new neighborhoods and were called upon frequently to do the work of dozens of laborers. Now, this forlorn bulldozer is looking for a new owner with an asking price of $9,000. Would you be interested in taking the vintage approach to moving dirt in your hometown? Thanks to Howard A. for another neat find from our hard-working past!
The road to modern mechanization was a rough one. Holt Manufacturing Company got its start in the late 1800s with the manufacture of steam-powered tractors. While these behemoths would do the work of a team of horses, they were outrageously heavy and difficult to navigate through soft soil. One of the Holt brothers came up with the idea of using a loop of metal belted tracks instead of wheels to get around this problem. This invention became wildly successful and led to a major expansion of the company. The invention was used in World War I not just for tanks, but the company’s tractors were extensively used to haul supplies and to assist in the battlefield engineering of the inhospitable terrain that defined that terrible war.
After the war, the company merged with the C.L. Best Tractor Company and changed its name to Caterpillar Tractor Company. The Depression hit Caterpillar hard, and the company survived by selling tractors and combines to the USSR while using the period to begin the changeover from gasoline to diesel engines. When World War II rolled around, the company busied itself with diesel engine production. Unlike other companies that scrambled to survive after the war contracts were terminated, Caterpillar was in the right place at the right time. Massive rebuilding efforts around the world required a tremendous number of specialized bulldozers and other machines and Caterpillar was there to satisfy that need.
One of Caterpillar’s most popular models is the D4. introduced as the RD4 in 1936, this medium-sized bulldozer originally weighed in at a stout 10,000 lbs. It was powered by a four-cylinder diesel engine with 43 horsepower, thus the “4” in the name. As time wore on, the model gained weight and boasted more power. However, the name stuck and a D4 model is still offered today by the company. The newest model puts out 130 horsepower and weighs just shy of 30,000 lbs.
The D4 you see here is a 1955 model. The seller tells us that it has a six-way blade and that the rear hitch is “just an ornament.” The hour-meter currently shows 3,000 hours of run time on this bulldozer. Unfortunately, the seller does not tell us if this is the 6U model with a 44″ track gauge or the 6U with a wider 60″ gauge. Interested parties can ask the seller for the serial number, which will have either 6U or &U as the first two digits. We are told that “both motors run well.” One would assume that there is only a single diesel engine powering this bulldozer, so the statement is a bit hard to decipher. Perhaps they mean the hydraulic pumps? If anyone with experience on or around these machines can chime in on the comments to clarify this statement, we would appreciate it.
It is hard to look at an old piece of equipment like this and not wonder where it worked and what type of work it performed. To state that Caterpillar equipment had a large role in building the world we live in today would be an understatement. Perhaps the best testament to this bulldozer is that it is still ready to move dirt 69 years after it slowly motored out of the factory. New models with a lot more in the way of safety features and creature comforts are available, but this one can still put in a day’s work. That says a lot after all those years. Hopefully, this one will find a home where it gets exercise and is preserved for the next generation of builders.
Have you ever driven a bulldozer? Do you think machinery like this should be preserved? Please share your experiences and thoughts in the comments.
I can help with the second motor. The snall gas gas engine on these were reffered to as “Pony” motors. You’d fire that little Pony motor up first, then with help from that it would fire up the bigger Diesel engine. I worked on a gas pipeline with 48 inch mains in the early 90s, they had Side Booms for lowering pipe down into the trenches, one old one Id hear a little gas engine, then the diesel fire, thats how I know. They were Caterpillars, basically looked like this machine here except it was built for moving pipe off the side. You would all have to look it up for pictures to get a better idea.
https://www.caterpillar.com/en/news/caterpillarNews/customer-dealer-product/pipelayer-anniversary.html
Here is a good article if anyone is interested.
Wow good link Driveinstile.
Curb weight 78000lbs, top speed 5.4mph lol. 🏁 Cool machine.
My dad bought a D4 Cat in the late 60’s. Driveinstile is correct re: the Pony motor. We used the heck out of that Cat, pushing brush and trees into burn piles, tamping sileage and whatever use that he or our neighbors could come up with.
Thought-provoking article Jeff. Perhaps we don’t stop to realize how machines like this revolutionized heavy construction….
The article reminded me of a conversation I had with my folks when I was maybe in grade school. We were on a rural two-lane traversing some hilly and rough terrain near where they grew up in southeastern Ohio. Somehow the road construction process came up. My folks explained that the road was built by WPA workers in the 1930’s (my folks would have been grade school or junior high age about that time, and remembered). They explained that the road was built using some heavy machinery, but much of it was men with shovels and teams of horses. I remember being floored by the discussion.
The next time you are in a road construction area, look around and realize how far we’ve come.
Yes this was a good feature. I grew up with Cats. Drove them, worked on them, even uttered a few less than flattering words in the process.
My Dad told me about one extremely cold morning when he tried to fire up the D2. It was 30 below so rather than just try to wheel that pony engine when it’s stuck with molasses, he’d just take out the tiger torch and warm it up.
So he set the torch on a piece of fence post and just aimed it up at a slight angle so as to warm up the whole crawler. Everything seeming safe he then went over to the barn to check on a heifer that was do to calve soon.
It took him a little longer than he expected and when he got back he was greeted with the side of the engine on fire (the hose of the torch had twisted and the flame was directed up along the side of the engine.
Well, Dad ran over to the shop and grabbed the old Pyrene extinguisher. He pulled the handle out and shoved it back in while aiming into the center of the fire. He had hoped to extinguish the fire but he didn’t expect the fumes from the Pyrene to come rushing back out at him.
Dad got a full whiff of that which knocked him cold. He came to a few seconds later and looked up at what he thought was a Cat burned to a crisp.
No harm done; the fire only burned a little grease off the engine. The Cat was actually thawed out and started just fine. He went out, fed his cattle then parked the Cat in the shop where there was enough heat from the blacksmith forge to take the chill out of the air.
Well, I bet you weren’t ready for this. First and foremost, I want to thank Jeff and the staff again for a(nother) well written, informative article. I realize this isn’t your everyday Barn Find, but if you are reading this, you’ve had a fascination with big, loud machines since knee high to a lug nut. Goes back to the sandbox as a kid, and of course, my favorite childhood book, Katy the snowplow. My mom read me that story countless times. My kids loved it as well, along with Virginia Burtons “Mike Mulligans Steam Shovel”. She personified big machines for kids. Katy( KT for Krawler Tractor) was a fictitious make, but had 55 HP and hydraulics, so was probably modeled after a D4.
As mentioned, the D4 was the ubiquitous dozer for many applications. Its biggest feature here is the hydraulics, as previously, dozers had a cable lift for the blade operated by the winch in back. Hydraulics after the war literally changed our lives. I saw a Modern Marvel show on hydraulics. You don’t want to know what’s in a modern jet.
The “pony” motor, you know, when I blab about the low HP of some foreign cars, that their motors start our bigger motors, there’s merit to that. Before electric starters were strong enough, a small auxiliary motor, of maybe 10hp, usually a gas Wisconsin flathead opposed twin. You’d start the pony motor with a rope start, and engage the pony motor to the diesel via a ” ka-chunk” dog clutch. Crude, but it worked. Not long after this model, Cat offered an electric conversion, I believe.
Ever since those “sandbox” days ( and appropriate noises) I surrounded myself with heavy equipment. Pony motors were a bit before my time, but I did run across an old grader that had one. As bigger demands required bigger machines, small dozers like this, through municipal auctions became the staple of the American farmer. The farm I lived on had the IH equivalent, (IH 500?) and no less stout. JD 450 was another. I worked for a trencher dealer that would convert 450s into cable plows. Natch, it was my job to deliver them. I got quite an education on the operation. Wet tracks on wet steel ramps is not for the faint of heart. Operating a dozer for a job is incredibly mundane, but a great M-F 7:00-3:30 job and you can’t get lost, and no pesky scales. Many burnt out truck drivers go into heavy equipment.
Thanks again to the staff for my kooky submissions.
Oh, one more thing( Columbo), you want to see what a D4 is capable of, there are several videos of the building of the Alcan highway. While the D8 was used for trail blazing ( what a job THAT must have been) the D4 was the all around clean up dozer. The Alcan highway was an engineering marvel in itself and the D4 was part of it. Fact is, any major construction endeavor had D4 Cats.
Today, modern dozers are epitome of refinement, with hydrostatic drive and laser operated grading, but back then, the steering was controlled by clutches that stopped each track, that required some hefty pull on the levers. It was no “girly mans” job, for sure. I never cared for equipment operation, being one of those girly men, I opted to sit on my butt in dump trucks.
Nice read. I do have limited experience with a dozer. For me , the sweet spot for a dozer is my 1996 Dresser TD7H. I say sweet spot, as it has the Joy Stick as more modern crawlers have , but with no computers. It weighs about 23,000 lbs and has about 75 horsepower with a 6 way blade. Have owned it about 20 years and we use it at hunting camp and farm. Absolutely love it for clearing trails , fixing roads and just general fun. Fairly easy for a good local mechanic to work on it as you don’t need to be a computer specialist. This one came with a new motor and undercarriage. Parts can become a problem, but they are simple to work on , except the transmission. The ole D4 listed here is one that would not want to tackle. But I do enjoy keeping mine is top condition.
Leave it to Howard to find something like this! As stated these were common as the dirt they pushed. Driveinstile covered the pony motor, I rebuilt one of those years ago, opposed twin w/ magneto. Never worked on a lot of construction eq., did rebuild a 2-53 detroit in a JD 440 track loader. Oldest thing I worked on was a prewar Hercules powered Cletrac dozer.(I’ll have to track that machine down make a great toy!)
How many remember Mechanix Illustrated and it’s stories about a salesman named Alexander Botts for the “Earthworm Tractor”?
My Dad would always mention:
” Earthworm tractor co. We plow deep while others sleep”!
If I showed a photo of this to my wife, telling her that I wanted to purchase it, after saying, “You’re kidding, right?”, she would probably be more open to just about any crazy vehicle that I come up with in the future. “Well, at least I talked him out of buying that ridiculous bulldozer…”
Actually, I think that was my Mom’s basic response to Dad about purchasing the his once the colorful bits of her response were deleted. However, she pretty quickly was persuaded about it’s usefulness.
Love these old cats. I actually run them for a living still. Not full time but I probably had about 200 hours in my 1955 Cat No12 grader just this summer. Pony motor and everything. Had to move it for some guys running electrical in a field and they were appalled it started up haha. When it’s warm out, I can have it going in a couple minutes. The key with keeping the pony’s going is always run them out of fuel when once the diesel is running. They make conversions for a direct start now but when the pony’s are running they work really well. Got a neighbor with a d6 I believe of the same year as this dozer and my grader but has the bigger 6cyl like my grader. Got to go pick it up since it’s free.
Seems a bit high priced, these can be had for a lot cheaper, even in running condition.
Great article I’ve had a d6 and a cat 12 grader both with pony motors never any problems
We had an annual Print Festival at the Art Center where I used to live. One year, they rented a small road roller (“steam roller”) to drive over a thick pad to make large format prints in the Art Center parking lot, which was shared with a town park. A car pulled in to go to the park as I was walking my dog nearby. Noticing the unattended roller, they asked me if they were paving the lot. I said, no, they’re holding the inaugural Annual Steamroller Race, and that only one team had arrived so far- the rest of the teams would arrive soon. Another car pulled in next to them. As my dog and I moved on, I could hear them discussing whether or not to move their cars so that they wouldn’t be in the way of the steamroller race.
The pony motor shared its cooling with the diesel engine and made the whole package warm, which made starting easier and more likely possible.
The pony motor shared its cooling with the diesel engine and made the whole package warm, which made starting easier and more likely possible.
I have operated many old CAT tractors before I retired from CTCO in east peoria Ill. in 1995. Most in plant dozers were built from surplus or salvaged parts for maintenance work and most had pony starter motors. I now own a 1985, 953 track loader and a 2022 skid steer that I love to operate at age 83. The pony motor exhaust was routed through the intake manifold on the diesel to preheat the injectors etc. System worked very well in cold weather.
LS swap
For the Pony Motor????????
Sorry, just couldn’t resist.
Not only do I remember Alexander Botts and the Earthworm Tractor Company, one of my sons gave me the 5 book set about his adventures for Christmas! Probably a result of my adventures with a 1930 Cletrac W model which we could only run with the blade straight. The clutches couldn’t handle it angled either direction, even in snow! However, it ran beautifully, started easily, and was a hoot to drive.
operating a dozer all day is all but mundane. I have been an operating engineer for 45 years. i have run every cat dozer made. Truck drivers complane about the old 5 and 4 transmissions, or how but there truck drove, all i can say, is try running a direct drive d 6 with a johnson bar, hand clutch,4 speed, hand clutch and foot brake steering, foot blade tilt, on a 2/1 slope when its snowing and 15 degrees out. You are dancing on pedals all day. But luckily and lunch you get to listen to the drivers complain how there heaters arent blowing hot enough
Hi str8rbill, perhaps mundane was a bit harsh, more like repetitious. I have a friend that was an operator for years, and he said, it’s almost to the point, all the operator does is forward and reverse. Like a pilot, basically just lands and takes off. I should talk about mundane driving a dump truck. One day I hauled 23 loads of material from one side of the pit to the other. The salvation there was I loaded myself. Fact is, years ago already, they began doing away with the operator and the truck drivers all loaded themselves. We always had kind of a “friendly” feud with the operators. One thing you never wanted to do, was pixx off an operator,,,
Nice to see this……We had one just about like this on the family ranch in Oregon. I spent a lot of hours in the seat in my youth. We would take the blade off and farm dryland summer fallow with it. Ours was a 1952 7U series. I think 1951 Or 1952 was the first year with electric start on the pony motor. Interesting fact…….John Deere’s model R tractor (their first diesel) had a pony motor very similar to the D4 Cats……a little unofficial collaboration, it seems. The next series of John Deere diesels had a completely different V4 pony motor.
Thanks for the memories……
Cool find. BF is having fun with oddballs. I had a Cat very similar to this, it was used for logging. The blade could clear a path and the winch could drag the logs out of the woods.
While it may be a 6 way blade, there is only one hydraulic “way”, up and down. The rest must be wrestled by pulling a pin and lifting/driving the blade around to reposition it. There is no on-the-fly tilt adjustments.
It is the operator that must be heavy duty! No suspension, except the pitiful springs in the seat cushion gave a punishing ride when it crashes over rocks. No muffler (whaaat), foot brakes, hand clutches, all are muscle powered. The driver ergonomics weren’t a consideration!! It was a young persons profession for sure.
These are capable, but excruciatingly slow with limited dirt relocating capability. A worn out 9K modern backhoe will accomplish far more in a day, and with a lot more comfort. Too bad the winch is DOA, as that log moving capability could be a still be a very useful tool.
It appears to be in good condition, with a lot of wear left on the grousers. Probably most of the undercarriage is still ok if everything has been greased regularly. The clutches and tranny and other parts are unknown and are a bear to work on when needed, the cost of which will be more than the asking price. You would have to drive it under a load until everything was hot to even find out if they were acceptable condition. By the time you reach this point the novelty might be gone already
It is hard to find heavy equipment for 9k, but this is still too expensive for this unit as it is too difficult to operate in real life anymore, and is more of a toy than a tool. As a ( not so fun) tool with occasional use, under 4K if in good condition and half (or less) that if ANY work is needed is more realistic. My .02 cents
So much response, who would have known.
At one point in my many occupational life I worked for a company that built gated communities and golf courses. The D-4 Cats were used for finishing work on the golf courses. A expert operator could move a small pebble and place it perfectly. On the other hand goofballs like me operated the big off road dump trucks. Great story guys.
God Bless America
Won’t fit in my garage so I’ll pass. Seriously though, I enjoyed this article and the comments. My career was in building construction. I got to see a variety of equipment in use. Nothing like feeling the ground vibrating when one of these rumble by. Like a lot of kids, I was fascinated with construction equipment and big trucks. Still am. Happy Thanksgiving everyone.
As a 6 year old in the late 1940″s we lived about a mile from a big rock quarry (now condos, what else?) which had a fleet of Mack Bulldog trucks (with the unique, except Peugots of an earlier time front end) with Pony motors which my father explained to me. We went often to watch the quarry operation which was in full view from the public road, drilling, blasting, and scooping up in the big Macks, then being screened for size, then loaded into highway legal trucks. I was convinced at 6 that I could boss the place. And yes, I really liked the stories of the Earthworm Tractor Co.
I hope somebody picks this up.
I had a cable operated D8 about this vintage I used to clear AZ dry washes. Cable jobs take a lot finesse to make em work and rock and stone wears out the under carriage & tracks like nothing else. I ran that old rig until the tracks were so worn out I was afraid to run it more. I put it up for sale for $3 grand & got no takers until some collector offered me a Fordson tractor, an old forklift & something else I’ve forgotten. I took the trade.
I’m still not thumbs up worthy, but I want to thank all that responded.
And, in the middle of the night, I remembered it was the Rowe Quarry, and, the Mack’s had chain drive. Just like my bicycle!
My Dad’ first dozer was an Oliver OC3 track loader. It was used to dig foundations/backfill when he was building homes starting about ‘47. He retired in ‘64- then started a dozer/dump truck business. Had a pair of Case 310s, IH TD6 Series 62, John Deere JD2010, TD9 dozer and a Cat 500. Ironically, he didn’t like the gated steering clutches, and it stick around long. I was about 15 when he bought me my own IH T340 dozer to play with. He only had one rig with a pony motor. He said it was double the work keeping both engines operable. Excellent article. Thanks for the trip down Memory Lane. Hope someone gives this old girl a home.
I was around all kinds of construction and farm equipment in my younger days, including dozens. One unmentioned aspect of operating a dozer (or any track machine of that era) was the relentless pounding you got from the grousers if you were working on hard packed soil or rocky areas. The chattering vibration from the tracks was tiring at best, and torture most of the time. I’m fortunate that my seat-time on tracks was limited; one of my contemporaries was one of the best operators I’ve ever encountered (he didn’t need laser guidance) and he stopped operating dozers at the peak of his trade because, as he said to me, “You don’t see many old dozer operators — they’ve mostly all died from kidney failure from the vibration of those old machines.” I’m told steel-wheeled farm tractors had something of the same potential depending on the circumstances of their use. I ended up on rubber tires for most of my life, on or off road. As several of you indicated, the old time Cat-skinners were a breed apart!