My husband has been working on replacing the balljoints on the drivers side of our bronco 4x4. He has put back the locking spacer and now he can't get it to tighten all the way or come back off. Is there some type of tool that is needed? Is it possible he has the spacer on wrong way? HELP!!!

http://www.napaonline.com/MasterPages/NOLMaster.aspx?PageId=470&LineCode=BK&PartNumber=7002467&Description=Ball+Joint+Spanner+Wrench