Expert: Skip Bollinger - 4/6/2007

Question
How do you install a alternator in a 85' cadillac sedan deville?

Answer
Kendrick,
  I have a Motor's Repair Manual that goes up to 1989 and all it says is "remove alternator and set aside" which leads me to believe it is so simple, I could do it. I'm a Parts Professional, NOT a Tech. That is stated in my profile. Here are my ideas and suggestions...
  First you should disconnect the + (positive) battery cable so you don't short out anything. This is a computer car so once you are done, you will have to reset the radio settings, seat settings etc. Whatever options the car has will need to be reset.
  Next you will need to have BASIC mechanical abilities and a BASIC hand tool set with Metric sockets, ratchet and extension.
  You haven't told me what engine you have so I'm GUESSING it is a Gas, NOT Diesel???
  IF you have a Gas engine, it should have a serpentine belt. Find the tensioner that maintains tension on the belt. There should be a bolt or a square hole for a 1/2" drive ratchet so you can "compress" the spring and remove the belt. Basic mechanical ability.
  Once the belt is loose, find the bolts that hold the alternator to it's bracket and remove them. Once the alternator is out, remove the wires going to the back of it. It may just be a plug, I'm not at work and can't pull the alternator to look at it. I think in 1985, GM still bolted the wires to the alternator. Just remove the wires and the alternator is out.
  Installing it is just the opposite of removing it. Just reverse the steps.
  I will suggest that, when installing the bolts that hold the alternator to the bracket, DO NOT TIGHTEN EITHER ONE UNTIL YOU HAVE THEM ALL STARTED!! You need to start the bolts and turn them about 2 turns and make sure they are threading into the bracket before you tighten them.
  Once the alternator is installed, "compress" the tensioner again, install the belt and all should be good to go. When installing the belt, MAKE SURE IT IS FIRMLY INSTALLED ON ALL PULLEYS INCLUDING THE CRANKSHAFT. This is a VERY COMMON problem with people that are novice a to auto repair. The belt has to be perfectly installed on ALL pulleys, including the crankshaft or it will self destruct. Check ALL of them...
  I hope this helps. Again, please remember I'm a Parts Professional, NOT a Tech but good luck.
Skip