Case study: Hitachi ZX130 (relevant to the ZX120 model also)
Recently a customer called us at OMP to say his ZX130 was very slow in all movements but with no sinister noises coming from the hydraulic pump. Our service department advised him over the telephone to carry out a number of checks to his pump. He carried these out via instruction from our team and it was obvious then that the pump required further investigation. He removed the hydraulic pump from the machine and brought it into our workshop.
The first step required our technicians to strip the pump. They found one of the swash supports damaged at the contact point with the servo control piston. On further investigation the servo piston itself was found to be completely worn away at the top, leaving a 10mm hole where the servo control oil pressure was escaping into the casin gand back to the tank. This resulted in no control pressure to signal the pump into action.
As part of the repair to the damaged parts OMP also carried out a hydraulic service on the hydraulic pump. This included a full set of bearings, seals, lapping of the rotor and valve plate on both rotary groups and a benchtest to ensure all was well before refit.
The hydraulic service carried out is recommended for the ZX120 and ZX130LCN after 8500hrs as the needle roller bearings in the pump centre are suspect if the hydraulic oil has not been changed every 1800hrs. The damage caused by a bearing collapse is catastrophic and in some instances can render the machine with a repair bill of €5 – €6k plus.
For details of an hydraulic service for any make of hydraulic pump please contact our service department at email@example.com or firstname.lastname@example.org. Alternatively you can send us your query through our contact form or CALL us on 086 252 9861.