Here is info from someone else who had PTO issues on his Massey 1100 ....might be applicable to you.
I have an 1100. The pto wasn't working so I took it to the shop. Turns out the bearomg high/low shaft is loose in the center housing. This caused the pto clutch housing to move out of alignment. This caused wear on the slip ring surface. This is where the hydraulic pressure enters pto clutch to make the clutch engage.
I am going to need PTO & Drum PN 523556m91 and center housing PN 522263m92 and who knows what else.