```html
THE Allis-Chalmers HD21A
The Allis-Chalmers HD21A is a large crawler dozer that was manufactured by Allis-Chalmers from 1957 to 1964. It was powered by a 6-cylinder, 2-stroke diesel engine that produced 212 horsepower. The HD21A had a top speed of 7.2 miles per hour and a drawbar pull of 45,000 pounds. It was equipped with a 12-foot blade and a hydraulically operated ripper.
The HD21A was a popular dozer for use in construction, mining, and logging. It was also used by the US military during the Vietnam War. The HD21A was a reliable and powerful dozer that was well-suited for heavy-duty applications.
**Engine**
The HD21A was powered by a 6-cylinder, 2-stroke diesel engine that produced 212 horsepower at 2000 rpm. The engine had a displacement of 844 cubic inches and a compression ratio of 16:1. The engine was equipped with a turbocharger and an intercooler.
**Transmission**
The HD21A was equipped with a 4-speed, constant-mesh transmission. The transmission had a top speed of 7.2 miles per hour and a reverse speed of 4.2 miles per hour. The transmission was also equipped with a hydraulic torque converter.
**Hydraulics**
The HD21A was equipped with a hydraulic system that powered the blade, ripper, and steering. The hydraulic system had a pressure of 2,000 psi and a flow rate of 40 gallons per minute.
**Blade**
The HD21A was equipped with a 12-foot blade. The blade was made of high-strength steel and was equipped with a replaceable cutting edge. The blade could be raised, lowered, and tilted hydraulically.
**Ripper**
The HD21A was equipped with a hydraulically operated ripper. The ripper had three shanks that could be raised, lowered, and tilted hydraulically. The ripper was used to break up hard ground and rock.
**Steering**
The HD21A was steered by a hydraulic system. The steering system was controlled by a steering wheel. The steering system was also equipped with a hydraulic brake that was used to stop the dozer.
**Operator's compartment**
The HD21A's operator's compartment was designed to provide the operator with a comfortable and safe working environment. The compartment was equipped with a heated and air-conditioned cab, a padded seat, and a steering wheel. The compartment also had a dashboard that contained a variety of gauges and controls.
```
THE BEST ALLIS CHALMERS HD21A SN 12801 UP PARTS MANUAL
FULL/COMPLETE VERSION
File Format: PDF
Compatible: All Versions of Windows & Mac & Linux
Printable: Yes
Downloadable: Instant High Speed Download
Requirements: Adobe PDF Reader
EASY TO UNDERSTAND/NAVIGATE
