A dirty or broken distributor cap may lead to a number of ignition problems in your Volvo 240. Consult your owner's manual for a regular interval to inspect your distributor cap for damage, excess wear, or carbon buildup.
Pull straight up on the ignition coil wire in the center of the distributor cap to disconnect it.
Pull straight up on the boot of the first spark plug wire to disconnect it from the distributor cap.
Install the spark plug wire onto the new distributor cap and make sure it is seated properly.
Continue to transfer each spark plug wire to the new distributor cap, maintaining the same arrangement of wires on the cap.
Once all of the spark plug wires have been installed on the new distributor cap, set the cap aside.
Use a flathead screwdriver to release the clip securing the distributor cap.
Remove the old distributor cap.