Annual maintenance:

  1. Open the hatch and remove the tool panel. Remove the carpet and spare  tire cover. Remove the spare, tools, etc. Open the battery box.
  2. Disconnect the ground cable from the chassis. Remove the negative  battery terminal. Remove the positive battery terminal. Remove the battery.  Use extreme caution to avoid getting battery acid or residue from the top  of the battery or cables in your eyes. Goggles are recommended. If the  battery brushes against your clothes, you can end up with holes.
  3. Clean the battery terminals until they are bright and shiny. Dull gray  won't do. If it is possible to check the fluid level in the
     battery, do so.  Fill to the rings. Wash the battery. Put it on a charger if possible.
  4. Clean the battery box, removing all corrosion. Wash the battery box.  After it dries, touch up the finish as required.
  5. Clean the battery cable terminals (all three) until the connection area  is clean and shiny. Dull gray won't do. Clean the connection area on the  chassis.
  6. Clean the speedometer/odometer drive electrical connector in the right  forward corner of the spare tire well (pre-'90 models).
  7. Raise the hood (bonnet). Remove the protective cap from the jump start  terminal and pull the protective plastic cover from the terminal. If you  are missing the cover or the cap, replace them - they are critical items.  If there is no cover, water will enter the connector and corrode the  connectors and wires, causing serious electrical problems.
  8. If the connections are clean and tight, replace the cover and cap. If  the connections show any corrosion or looseness, disassemble, clean and  reassemble.
  9. Jack the right front of the car so that you can SAFELY work underneath.
  10. Remove the ground cable that runs from the right side of the engine to  the chassis. Clean both ends of the cable, and check for corrosion in the  cable. Clean the connection points, and replace the cable.
  11. Check the heavy cable connection on the starter solenoid for looseness  or corrosion.
  12. Check the moderately heavy wires on the same connection for corrosion  and breaks inside the insulation. These carry the charging  current from the  alternator.
  13. Check the small yellow wire connection for corrosion and tightness.  This wire triggers the starter solenoid.
  14. Lower the car. Fold back the carpet and open the central power panel cover.
  15. Check the main power connections at the top of the panel for tightness  and corrosion.
  16. Check the ground connections above the panel for tightness and corrosion.
  17. If you are having electrical problems, remove each fuse and reinsert  three times. Check the fuses for the proper value, and examine them  visually for damage or corrosion. Test them is desired. Later cars have a  fuse tester built into one of the relays.
  18. If you feel that it is necessary, remove and reinsert each relay. This won't be easy, as they fit very tightly in some cases. Porsche sells a  relay removal tool, but I am not impressed. It is basically a pair of  pliers with square jaws, and will pull the relay apart. One tool  that works well is a spark plug boot removal tool. It is a thin but strong  sheet metal  tool shaped like a "J" with the top 1/8" bent over at a right angle. You  can put this angle under the bottom edge of the relay and lift it out - IF  the battery is disconnected!
  19. Close the panel and replace the carpet.
  20. Replace the battery. Install the positive cable. Install the negative  cable. Put a drop of oil on each nut. Connect the chassis end of  the ground  (negative) cable. Lubricate the battery box latch and close the box.
  21. Lubricate the wiper drive shaft and hatch latch mechanism.
  22. Clean the spare tire, jack and tools. Put a couple of large heavy  plastic garbage bags in the spare tire well for emergencies, along with a  tube of hand cleaner and some paper towels. Install the cover and carpet.
  23. Lubricate the jack, and put it inside the tool panel. Clean and  lubricate the tools. Reinstall the tool and tool panel.
  24. Reset the clock and radio presets.

    A couple of hours of quality time with your 928 once a year can forestall  many problems.

     Wally Plumley
     928 Specialists