I have a 1978 3130 that i purchased from my uncle 20 years ago, it had 3100 hrs on it, now it has 5750 hrs on it.Lately the hydraulics have been giving me problems, 3pth shivers on its way up, remotes are also slow, the main front pump also has slight knocking sound when operating.When the tractor is worked for hours,it loses all hydraulic function, has no steering and no lift at 3pth. If you go back next day and start it up,all functions return but at reduced levels like before.I have been changing hydraulic filters and oils lately but has not helped, anyways i talked to a retired JD mechanic who worked on these tractors,his comment was the inboard break pads are causing the problem, they are disolving and getting into the hydraulic oil and plugging filters and fine mesh and contaminating the whole system.This is what is causing the shivering he claims, anybody have this problem?Thx for any comments in advance.....john