Replacing a junk cars distributor cap and rotor:
The distributor and rotor send nigh-voltage current to the spark plugs. Both should be checked periodically for wear or damage. Remove the rubber or plastic protective cover over the distributor cap with your fingers, or if it has fasteners, use a screwdriver. Release the cap from the distributor with a screwdriver or a nut driver; the screws will remain in the cap. Or, if two spring clips hold the cap in place, push them outward to free the cap.
Turn over the distributor cap and inspect it. Check for signs of deterioration: burns or pits on the metal contacts, and carbon tracks on the cap. Next, twist the cable boots off their towers one at a time and look for carbon tracks and cracks or other damage to the cap. If the cap is in good condition, clean it inside and out with a dry rag. If the cap is faulty, replace both the cap and the rotor.
With the new cap installed, hold the old cap and cables beside it. Remove the boost of one cable at a time from the old cap and fit it snugly onto the corresponding tower on the new cap.
The rotor receives high voltage from the coil at the center post of the distributor cap and distributes the power to the spark plug cables as it rotates. Grasp the rotor as shown and lift it straight off the distributor shaft. Inspect the rotor for pits, carbon tracks or other visible damage. If the rotor is faulty, replace both the rotor and the distributor cap. Place the new rotor on the distributor post, rotate it until they are aligned and gently slide the rotor down. Some rotors have retaining screws; remove the screws, position the new rotor and screw it in place.
More repair tips