Idler Arm Replacement

I have a 95 CV and the two bolts that hold the idler arm to the frame are next to impossible to remove. I did manage to get the top on off after about 2 hours of wrestling with it, but the bottom one is a real tough one to get off. The nut size is 11/16 inches with an open end but when I try to put a deep socket on it the 11/16 won't fit on?
Can't figure. There is very little room to work because of the transmission lines are in the way.
Anyone got a tip or two on how to go about getting this idler arm off?
It squeeks from time to time when I turn the wheel and the squeeking is driving me nuts.
Is this something that I should bring to a garage to have done?
Thanks for any replies.

A 17mm or 18mm is close to a 11/16 try one of these deep sockets. If the box end of an 11/16 fits good put a 3/4 inch loop the open and box end this will give you more pulling power.
I would use a 1/2 breaker bar and a six point socket that fits.