Allis Chalmers HD21 Dozer

Just like a shark cruising the beach line a 30 ton bulldozer can sneak up you. I know it sounds silly but such was the case with this behemoth Allis Chalmers HD21 dozer. People coming across this iron lump were often heard muttering excited utterances like “holy s@*t” or “oh my God.” Clearly this is divine heavy equipment.


There were so many details about this dozer I wanted to capture that video was the only option. You’ll notice the steady stream of people milling around the machine. Many climbed onto the seat and mulled over starting it up but most were not that brave or foolish. I don’t think anyone had a clue of how to get it running. There was a small stack that ran from the operator controls directly to the engine. A large quantity of starter fluid cans were found in this area leading me to believe this was a factory option for starting the massive inline six turbo diesel. As you can see someone installed a new exhaust tip not too long ago. Turn key? LOL. Even to a novice like me there were plenty of problems to be spotted on this old machine. The blade cylinders were leaking all over the tracks and the cylinders the run from the push beam to the back of the blade were completely sheared off.

But who cares about that. This thing was cool. Have you ever seen such a mean looking attachment as the Zor Plow? It would make He-Man jealous. Basic research pegs this device as used to provide drainage for farm fields and to lay cable/pipe at depths of up to six feet. Based on some of the other equipment on this dozer I’m thinking it was used for both activities. Logos on the side indicate this AC hails from Fiat-Allis era which puts the production age of the machine around 1975.

Here is a video of a HD21 running.

And here is a video of a Zor Plow in action.

BTW, This was seen at the Empire Farm Days equipment auction outside Seneca Falls, NY.

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4 Responses to Allis Chalmers HD21 Dozer

  1. Charles h tappe jr says:

    We have a ac 16 a ac sideboom 16B a ac hd5 with a wench a hd5 track loader a model d maintainer plus others

  2. Charles h tappe jr says:

    Looking to start old equipment show in bremhan texas looking for more old equipment not to sale just save a show we have draglines loaders bulldozer

  3. Beau says:

    I bought a hd21 cheap, don’t know anything about it , got it running and move 70 ft strait couldn’t get it to turn before it started to run out of fuel heard something about the fuel system has to due with it turning , huhhhhh ????

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