First of all I believe you can change the belt on the 87 by removing the bottom bolt on the alternator and letting it swing up. Install the new belt and carefully pry the alternator down to slip the bolt back in. Secondly as much of a believer in top quality proper tools that I am,here is where I take exception. For the holding tool I shortened the short end of a cheap 5 or 6mm allen and stuck a 6 inch piece of fuel line on the other end. I also changed the 90 degree angle to about 110 degtees. I took an 8mm allen,shortened the short end,and stuck the long end in a section of close fitting metal tube. I used good old duct tape to keep it from sliding out. I can't count the # of 103 engine water pumps I've replaced with these home made tools. By the way the 8mm allen has to be GOOD QUALITY.
Auto Zentral Ltd.