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Symptom
Possible CausesRemediesPiston rod scored Contamination of the oilContamination of the gland bearing Gland bearing failure Flush entire hydraulic system Change all filters Check gland bearing Cylinder bore scored Contamination of the oilPiston bearing failure Flush entire hydraulic system Change all filters Check piston head bearing Bent piston rod Operation problem: possible overload Outside impact Under specification of piston rod Check operation parameters Increase rod specification Split weld on base and ports Shock loading Poor original weld Check operation parameters M/c off & re-weld correctly Eye bearing broken Shock loading Under specification of bearing Overloading of cylinder Check operation parameters Increase bearing specification Increase clevis pin size Rod worn on one side Lack of bearing support Too much side load Rod too small Increase bearing area Change operation Increase rod size Incorporate external guides Gland blown out Possible intensification of internal pressure Threads worn Deformation of cylinder tube Check hydraulic valve operation Check threads Check tube for oviality & thread wear Leaking from around the gland od o-ring failure cracked gland Check clearances Fit back-up ring to o-ring Crack test gland Piston rod pitting Corrosion Upgrade rod material to marine specification Protect rod from weather Barrel internally corroded Water in the oil Change oil Protect from water ingress Regular seal leakage Incorrect seals fitted Seal grooves corroded or marked Air trapped in the oil Incorrect metalwork clearances Contamination of the oil Seals fitted incorrectly Seal housing sizes incorrect. Check seal compatibility with conditions Check all seal grooves for marking & corrosion Make sure cylinder is bled correctly Check oil for contamination Check condition of all running surfaces Cylinder is getting hot Internal leakage Test for internal pressure bypass Strip cylinder and inspect piston head & bore of tube Remove piston and check internal seal Rod kick up at end of stroke Internal bearing wear Incorrect alignment of piston to gland Strip and inspect piston head & gland bearings Check alignment of piston to gland Piston rod will not retract Internal leakage Port blockage Strip and inspect piston head & tube Check ports and pipes for blockages Check valve operation Loss of power Internal leakage Hydraulic pump failure Valve settings incorrect Strip and inspect piston head & tube Check pump & valves Slip stick or juddering Lack of lubricant for the gland bearing & seals Rough surface finishes on rod or tube Lack of hydraulic pressure Vacuuming or air entrapment Bearing tolerances too tight Seals too tight
