69 Coronet
Do these thread in and out? Lefty-loosey, righty-tighty? I had a 36" pipe wrench on it and nothing! Maybe heat...............

 

if they are shaped a little box like, they thread out. look at a new one. heat will help and yes they are hard to turn. try a little tightening first. a spray of rust buster a few hours before might not be a bad idea. they do sell sockets for that. i have the small and the large ones if someone wants to buy them :-)

they come out counterclockwise looking down on it from up top.

 

btw, did you split the joint yet? after splitting it, put the nut back on for a few turns to hold the arm in place.

 

p.s. if you use heat get as much of the grease and boot off the joint before it starts smoking.

 

everybody likes doing their own thing :-)