进口的隧道挖装机经长期使用，液压系统损坏严重。由于原厂已停产，恢复维修成本高，配件购置困难。针对原机使用中的问题和液压元件不同的损坏情况，用标准系列的通用进口件和国产件代替原装配件，改造原液压系统中不合理的部分，恢复、提高挖装机的技术性能。

After longperiod use of the imported crawling loaders, the hydraulic systems of the crawling loaders are damaged seriously. The original producer of the crawling loaders does not manufacture such type of loaders any more, therefore the cost of recovery repair is high and the parts for the repair are difficult to purchase. On basis of analysis on the problems occurring during the service of the loaders and the damages of the hydraulic elements, the improper parts of the original hydraulic systems are renovated by adopting standard series of imported parts and Chinamade parts, so as to resume and improve the behavior of the crawling loaders.