The specific reasons for the lack of pressure rivet machine: 1, pressure valve spring loose, such as pressure after no change may spool due to long-term use of wear and leakage caused by lifting pressure; 2, hydraulic pump long-term wear and leakage; 3, day hot oil temperature is too high, hydraulic oil is too thin to lift high pressure 4, cylinder piston head seal wear or aging caused by oil string can not lift pressure 5, solenoid valve use too long, spool wear, 6, the pressure one-way valve (if you have on the fuel line) leakage 7, oil pressure pipeline, cylinder solder joints, piston rod seal, etc. leakage 8, insufficient fuel tank, oil filter suction;