I used a regular 1/2 inch drive ratchet wrench and got the calipers off. I didnt personally need a breaker bar but it sounds like you might... get something long that will fit around the handle of your wrench and use it to get more leverage. If you don't really know what you're doing I'd take it to a good mechanic, brakes are something you definitely do not want to fudge on. If you dont have a repair manual like a Chiltons or Haynes then get one, they can be a big help sometimes. Other times completely useless, but it cant hurt.

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1985 CA 300D Turbo , 213K mi