Your plan is solid. I use compressed air to clean the aystem, and also to check for leaks using soapy water. I've also used nitrogen for the same thing.
You can try to use a socket on the main shaft nut to break it loose he man style. If it doesn't come loose then you got serious issues.
You can try to use a socket on the main shaft nut to break it loose he man style. If it doesn't come loose then you got serious issues.