Originally Posted by
Jeff Wills
If it's this freewheel, you can pry out the seal on the outside surface of the freewheel body and really clean out the innards. This will allow you to run lots of solvent and/or oil into the freewheel bearings. I agree that removing the freewheel completely will make this much more effective.
Hey Jeff, now that you've used my picture, I'll need to comment!
I was trying my best to stay out of this one.
OP, if by chance you have removed the tire from the wheel, remount it. It provides significant grip for leverage, especially when using a long wrench or air impact wrench/hammer. I'm guessing that if you damaged your tool trying to remove the freewheel, you had the wrong tool. Although, with that said, my very thin walled Regina/ATOM tool is what fits this freewheel, and I can see that it might not be beefy enough to stand up to the needed torque. There is a Shimano tool which has about 2-3 times the wall thickness.
The "Flush and Fill" method is recommended by lots of people, but originally your freewheel came with grease. Grease protects the internals significantly better than oil and will last for a very long time, especially modern synthetic grease, which has the added benefit of being very salt and moisture resistant. If you live near an ocean or live in a northern area where winter road salt is used, you will appreciate this added protection.