mostly construction equipment such as kranes and bulldozers
firs step check the fluid level,then see what part has failed or is not working if you find a leaky hose put the boom on the ground work the control valve remove the hose get a new one made install operate to bleed out air check for leaks,if a part of the system is not working suspect filters first then look at the controls,linkages then get a hydraulic flow chart to see whats on that circuit then go to tests and start running tests like pump pressure or control pressure and so on you will make a mess for sure
First, get tools. Then figure out what's wrong. Use the tools. Then go from there.
