Distributor Cap

• The distributor cap is responsible for directing the electrical flow from the ignition coil to the spark plugs; it is important to make sure this part is working properly. Remove the distributor cap to inspect for damage, corrosion, overheating or any other visible wear.
  
  

Air Filter

• Remove and clean -- or replace -- the air filter of the 1985 Ford F-150 about once a year. This ensures a clean air-intake system. The air filter is located on the top of all three available engines.
  
  

Transmission Fluid

• The transmission fluid should be drained and replaced -- in automatic and manual transmission F-150s -- every two to three years. This fluid does not undergo strenuous duties like engine oil, and does not require frequent replacement.