| Hi Dave,
You shouldn't have any problems removing the cush drives, you'll need a 14mm allen key, or better a 14mm hex. bit socket to hold them whilst you're undoing them. They are not particularly tight in the original sprocket, or the carrier.
If you do have to drift the old ones out if they've corroded in, make sure to use a piece of tube or (Haynes special!) suitable sized socket (ouch!) rather than hitting straight on the stud, so that you don't risk breaking the rubber bond.
Whilst you're at it why not fit new ones, they're not particularly expensive?
Hope this helps.
Regards, Pete | 
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