I am rebuilding an Oliver 1650 and have the hydrapower unit off the tractor.  When I drained the oil in the rear end, I found small roller bearings that I eventually identified from my shop manual to be thrust bearings from inside the differential.

To get to them to change them, I have to take off the brake housings.  But, for some reason, I can't get them to budge.  Any suggestions?  I hate to try to use a chisel to pry them off, but what other options do I have?

My shop manual says to pull out the bull gears before removing the differential, but, by studying the manual diagrams, it looks like I should be able to just pull out the brake housing and gears one side at a time to get to the thrust bearings.  Is this correct?  

Any suggestions would be appreciated.