Making the Grade: Caterpillar Auto Patrol

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Don Bartholomew’s 1933 Caterpillar Auto Patrol No. 7 grader, serial no. 6D47.
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Don with a Caterpillar 60 “snowplow special” in his collection.
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Front view of the 1933 Caterpillar Auto Patrol No. 7 grader. The grader weighs 10,900 pounds.
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View of the Auto Patrol’s steering system.
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The familiar Caterpillar logo appears on the Auto Patrol’s radiator.
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Don gave the Auto Patrol extra-close attention, as this photo shows, in his first-ever full restoration of an antique tractor.
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Rear view of the 1933 Caterpillar Auto Patrol No. 7 grader. The rare piece was displayed under a tent at Caterpillar’s 75th anniversary display in 2000.
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When Don started working on the 1933 Caterpillar Auto Patrol No. 7, it only had one tire; the rest had rotted away. “It needed everything,” he says, “and it needed a lot of work.” The Auto Patrol’s 4-cylinder, 40 hp engine was also built by Caterpillar.
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The Auto Patrol’s front end.

Don Bartholomew was just a boy when he became hooked on Caterpillar equipment. When he was in grade school, he watched the reconstruction of a road in front of his home. Every day, as he went to school and returned home, he saw the big equipment at work. “I was always impressed by it,” he says. “In the morning they would start those big engines, and that always stuck in my mind.”

When he was in high school, he worked part time for an International Harvester dealer. After military service, he worked for an Oliver dealer and he began collecting Allis-Chalmers tractors. But that came to a screeching halt in 1963, when he took a job at Ziegler Caterpillar in Minnesota. There, he says, collecting the wrong color of equipment “might get you in trouble.”

Scouring the country for parts

At Ziegler, Don worked as a senior buyer for the company’s General Tractor division, and it was work he enjoyed. “General Tractor was Ziegler’s used parts division, selling only parts,” he says. “It was like a heavy equipment junkyard. Ziegler had a used equipment division, and we sold parts to them. These were parts to rebuild Caterpillar tractors for resale. That had been part of William H. Ziegler’s idea for the company from the beginning.

To find inventory, Don traveled widely. “I went wherever I wanted to go to buy Caterpillar machinery to be dismantled for parts, depending on what was needed or what someone called us about,” he says. “If someone needed parts for a D9, that might be more difficult and require more travel than finding parts of a D8, say, because many more D8s had been manufactured.”

Sometimes he’d buy entire machines. For example, a contractor might tell Don about a D6 with a failed transmission. Repairs could be so costly that the owner would offer the unit to the General Tractor division. “I’d go all over the country and see old equipment and contractors’ shops,” he says. “I’d find Caterpillars that we’d dismantle and sell the parts. That’s how I got familiar with different equipment.”

Finding a rare grader

About 30 years ago, Don bought a pair of graders from collectors in northern Minnesota and hired a contractor to haul them to his hobby farm. “When the trucker was coming down toward Minneapolis, he gave me a call and said he’d asked for some assistance to get the grader on a low boy. He said, ‘There’s a guy up here who has a grader that he wants to sell, and it’s just like the other one I’m going to haul down to you. Do you want it?’”

Don thought the price was right, so he gave the trucker the green light. “He hauled them one at a time down to Faribault, Minnesota, where I stored my stuff at the time,” Don says.

The graders stayed there for several years before Don took a look at them. What he found in the added-on Caterpillar was a surprise. It had only three control stations, which meant it couldn’t be a No. 9 or a No. 11 grader, which was what he had expected: Both of those models have five stations. Equipped with three control stations, the rig had to be a No. 7. Through serial number research, Don learned that the Cat was a 1933 Caterpillar Auto Patrol No. 7 grader. He would later learn that it was a rare piece.

By then, Don knew that Cat graders had been manufactured in Minneapolis, but the assembly line had been moved down to Peoria, Illinois. “I was telling some people what I had,” he says, “and then I found out that this one was the first one to come off the assembly line in Peoria. That made it special.”

Showcased at Cat’s 75th anniversary

Through the course of a 40-year career with Ziegler, Don had built close relationships with Caterpillar engineers and managers in Peoria. They were so impressed by his Auto Patrol that they asked if he would restore it for the company’s 75th anniversary celebration in 2000. Don had done basic work on tractors in his collection, but he’d never tackled a full restoration. The 1933 No. 7 grader, he says, seemed a good place to start.

Because Don’s Auto Patrol was the first motorized grader built by Caterpillar, company officials were eager to showcase it at the anniversary display, which was held west of Peoria. “They’d bought out Russell Grader Mfg. Co. in 1928, so they had Russell motor graders,” he says, “but they wanted this 1933 Auto Patrol Grader No. 7 for the festivities.”

Complete restoration for decades-old grader

In the fall of 1999, about nine months before the anniversary display, Don started work on the Auto Patrol. “It needed everything, and it needed a lot of work,” he says. “It had only one tire. The others were all rotted off the rim. It didn’t have a moldboard, because someone had taken it off to use for a back blade or something, but the No. 7’s moldboard is the same as the one on a No. 9, and I had two of those machines, so I scrounged a bunch of parts from the 9.”

Don went completely through the grader’s engine, boring out two barrels and sleeving them back to standard, as he had a set of standard pistons for the 4-cylinder engine. Seals in the differential around the wheel seals needed to be replaced, and work was needed on the control box, hafts and bushings. After an extensive paint job, the grader was ready for its debut at the Peoria event, where Don would drive it in a parade.

A handful to drive

That’s when he discovered that driving the Auto Patrol was no easy job. “It steers hard because it doesn’t have power steering or anything,” he says. “That’s the way it was designed and manufactured. When it’s sitting still, you can hardly turn the wheel. You have to move it back and forth a little bit in low and reverse so you can move the steering wheel.

“That meant it was a pretty tough go every time I backed it into my shed, because to get it in I had to turn the wheels back and forth so much. It doesn’t have the leaning wheel that makes it easier. That didn’t come until a number of years later.”

Otherwise, he says, operation of the grader is straightforward. “It’s like driving a straight-geared farm tractor,” he says. “It growls and rumbles, and it just has a mechanical brake drum on the pinion shaft of the transmission that stops it. This had only one drum on the pinion shaft of the transmission, both for the foot brake and emergency brake.”

Rarely on the road

Other than the Caterpillar anniversary display, the only other place Don displayed his Auto Patrol is the Le Sueur County (Minn.) Pioneer Power Show. It was just too big to haul around to shows, Don says, adding, “You have to have a lowboy. It’s pretty expensive to move it around.”

For a few years, Don kept the No. 7 at his hobby farm, in a machine shed with four sliding doors. It was a bit of an ordeal to get it under cover. “I had to clean almost all the machines out so I could get the angle to put it in lengthwise,” he says. Finally he decided that he’d had enough, and in 2015, he sold the grader.

Built in small numbers

The No. 7 was equipped with Caterpillar’s standard 4-cylinder gasoline engine. “With that machine, this same engine was used for power to run the belt that brought the dirt up to where it could be loaded in wagons, or from the ditch to the middle of the road, where it was bladed out,” he says. “That was how they made the roads in the old days.”

The Auto Patrol was used to grade roads at a time when most roads were gravel. “Beyond that, all the other history is lost,” Don says. “The guy who actually bought it for me and brought it down said the seller had no connection to the machine at all. It was on his property when he bought the land, and he knew nothing about it. Because it was in Minnesota, maybe Ziegler sold it, but it’s pretty difficult information to look up, because nobody kept a record of the serial numbers and buyers at a particular dealership.”

As the years passed, Don came to understand that his restored Auto Patrol was a rare survivor. “At one point I might have thought it was the only one left,” he says, “but then I talked to a young fellow from Montana who has one that belonged to his grandpa. It was used to work roads on a ranch there. Another guy called me to say he had one, but he wouldn’t give me the serial number, so I don’t know if he actually had one or not. So there’s at least one more out there, but I don’t know about any more.”

One thing’s for sure: You won’t run into a lot of these. Caterpillar built only 125 Auto Patrol No. 7 graders. FC

For more information: Don Bartholomew, 13630 Yale Ave., Hamburg, MN 55339.

Bill Vossler is a freelance writer and author of several books on antique farm tractors and toys. Contact him at Box 372, 400 Caroline Ln., Rockville, MN 56369; email:

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