I have a 1965 John Deere 3020 gas with single SCV's and the actuator valve just forward of the dash on the left side has a slight hydraulic leak. It is dripping on the rear of the exhaust manifold and I need to fix the leak. We took the hood off and could identify it was leaking underneath the valve where the "cover" is. Looks like 3 bolts secures the cover and it has some o'rings and packings for seals. If I take the three bolts loose and remove the cover will anything fall out from above? Believe there is some kind of centering shaft above it. Just want to put in new o'rings and packing without removing the selector valve. Any insights and advice would be appreciated. I looked at the service and parts manuals plus ITT manual without getting any definitive guidance. SCV valve and couplers work fine. Thanks in advance.