There should be no need to cut any bearings off on the intermediate sheave the bearings on each end are a slip fit, not a press fit.
I prefer using a small chunk of 2x4 to keep sheaves spread if need be, the safest route is to just pull the outer pulley off the top sheave so you don't have to jack with the spring loaded setup at all.
Looking at the JDparts page here are the key #'s you need to do a rebuild:
2, 7, 9, 15 - on the pic. of the sheave guts, sec. 121 p. 34
bearing 5 (qty 2) in sec. 121 p. 32
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