Suddenly not enough check hydraulic system using methods
(1) check the cylinder inner-leakage in the hydraulic system. Rises in the hydraulic cylinder is the most easy way to see if there are obvious free fall. If drop significantly then remove fuel tank check and seal if it is worn it should be replaced.
(2) check the hydraulic valves. First of all clean the pressure regulating valve, check that the valve is worn, wear and should be replaced. Pressure regulating valve after installation if there is no change, then check the valve spool for wear, its clearance limit is generally 0.06mm, wear should be replaced.
(3) measuring the pressure of the hydraulic pump. If the pressure is low, adjust pressure adjustment, then a severe wear of the hydraulic pump.