Dongfanghong starts at 485. How to adjust it when there is no gas and no fire?

Purify the air. According to the configuration of Dongfanghong Yangdong 485, it is known that there is air in the oil circuit, and the oil circuit is blocked and cannot be started. The air in the low-pressure oil circuit should be removed. Dongfanghong is one of the influential tractor brands in China. In the era when China was short of food and clothing, Dongfanghong tractor completed more than 60% of the country's mechanized cultivated land, which once became synonymous with agricultural mechanization in China.