john deere 755 pto

[bohaslup123]

have a john deere 755 with 1600 hours that i recently purchased. the overall condition is very good with eveything working as it should with one exception.the pto fails to cut off or is VERY slow to disengage.This tractor uses a hydraulic pto clutch and pto brake. The linkage to the pto is free moving. I beleive this problem is due to worn brake disc. has anyone had this problem and what internal parts need replacing besides the disc???