I recently had to replace the clutch disc in my 1953 Ford Jubilee tractor. I re-assembled the clutch & it performed excellent along with the other components such as hydraulic system, lift and proofmeter. However, the PTO will not engage. The PTO was operating excellent prior to splitting the tractor. The tractor does have hydraulic pressure because the lift works. The shop manual indicates it requires hydraulic pressure to disengage the PTO, however it makes no mention of hydraulic pressure to engage it, nor does the shop manual give any trouble shooting guidance.