Good day everyone! I have a Cat 305C CR s/n HWJ005XX, on loan that I´m looking into purchasing. The current owner told me he had a issue with the swing/rotation of the machine. When he had a full bucket far reach, and turned the swing to the left, the machine kept going(swong freely). But only when turning left, and when the machine is warm, it does not do this when cold. I´ve tried to provoke the machine to do this, by getting it warm and swinging it(In a safe place). But I cant seem to make it fail, like the owner says it does. Is there anything I can check? Pressures, controls i.e? I have worked as a service tech on rock crushers, so I have some experience with hydraulikks and CAT enigines, but this is my first time trying to fix a excavator. I would greatly appreciate any help about this issue! Thank you!
Check swing pressure
Maybe a dumb question, but should not the issue be on both ways if so? There is only one double working valve for the rotation right?
U have one relief valve for each direction They are in the head of the swing motor
If there are mechanical noises, like grinding, scraping or popping, I would suspect the swing brake. If there are hydraulic noises, I would suspect something akin to what DEMLONE70 suggested.