Distributor Overhaul 6.0L/7.0L

Notice: The ignition system distributor driven gear and rotor may be installed in multiple positions. In order to avoid mistakes, mark the distributor on the following components in order to ensure the same mounting position upon reassembly:

1. Remove the two screws that hold the distributor cap to the distributor housing.
2. Remove the distributor cap from the distributor housing.
3. Remove rotor from the shaft by lifting straight up.
4. Mark the distributor shaft, and distributor drive gear for reassembly.



5. Support the distributor drive gear in a V-block or similar fixture.
6. Drive out the distributor drive gear roll pin with a suitable punch.



7. Remove the driven gear, round washer, and the tang washer from the distributor shaft.



8. Remove the distributor shaft from the distributor housing. If the shaft cannot be removed from the distributor housing due to varnish buildup, follow these steps.

•	Remove any burrs from around the roll pin hole in the shaft.

•	Secure the distributor housing in a vise, with the gear end down.

•	Use a cloth dampened with varnish remover to clean the shaft.

•	Do not allow the varnish remover to travel up the distributor shaft. This may remove the lubrication from the grease pack area.

•	Use a twisting motion to pull the shaft out of the housing.




9. Remove the distributor shield lock retainer ring and discard. A new retainer will be needed during assembly.



10. Remove the distributor pickup coil shield.



11. Disconnect the distributor pickup coil wiring connector from the ignition control module.
12. Remove the distributor pickup coil.



13. Remove the distributor pole piece pickup using a bearing puller.



14. Remove the two screws that hold the ignition control module to the distributor housing.
15. Remove the ignition control module from the distributor housing.

Tools Required

J 24642-F Module Tester

1. Inspect the distributor cap for cracks or tiny holes. Replace the cap if it is worn or damaged. Also, inspect the cap for signs of carbon tracking. Replace the cap if carbon tracking is present.
2. Inspect the terminals in the distributor cap for corrosion. Scrape them clean with a knife or if the corrosion is severe replace the cap. Make sure the rotor brush, (in the cap), has freedom of movement and no excessive wear. If the brush is stuck, worn or broken, replace the cap.
3. Inspect the rotor terminal segment for wear or burning. If the terminal segment appears corroded or burned, replace the rotor. Inspect for excess amount of carbon dust inside the rotor cup. If carbon dust is excessive, replace the rotor.
4. The rotor should fit snugly on top of the shaft. If not, replace the rotor.
5. Inspect the timer core on the shaft for cracks or damage.
6. Inspect the teeth of the stationary pole piece for wear. Wear would indicate that the timer core teeth have been hitting the stationary pole piece.
7. Inspect the shaft for shaft to bearing looseness. Insert the shaft in the housing. If the shaft wobbles, replace the housing and/or shaft.
8. Make sure the baseplate is tight on the stem of the housing.
9. Inspect the housing for cracks or damage.



10. Measure the resistance of the pickup coil with a Digital Multimeter, (DMM).

10.1.

Connect a DMM to either pickup coil lead and the housing, (1) The reading should show an open circuit. If not, replace the pickup coil.

10.2.

Connect a DMM to both pickup coil leads, (2). Flex the pickup coil leads by hand at the coil and the connector to locate any intermittent opens. The DMM should read a constant value in the 500 to 1500 ohm range. If not, replace the pickup coil.

11. Check the electrical performance of the module. The module can only be checked with an approved module tester, such as the J 24642-F . Follow the tester directions precisely.

1. Coat the bottom of the ignition control module and mounting area on the housing with silicone dieletric grease GM P/N 1974984 or equivalent.
2. Install the ignition control module to the distributor housing.

Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

3. Install the two screws that hold the ignition control module to the distributor housing.

Tighten
Tighten the screws to 1.7 N·m (15 lb in).




4. Install the distributor pole piece pick-up.



5. Install the distributor pickup coil.
6. Install the distributor pickup coil wiring connector to the module.



7. Install the distributor shield onto the coil.



8. Install a new lock retainer ring to the distributor shield.



9. Lubricate the distributor shaft, and lower housing bearing with a few drops of engine oil.
10. Install the distributor shaft into the distributor housing.



11. Install the tang washer.
12. Install the round washer.
13. Install the driven gear onto the distributor shaft.
14. Line up the marks on distributor shaft, distributor drive gear.



15. Support the distributor drive gear in a V-block or similar fixture.
16. Drive the distributor drive gear roll pin in with a suitable punch.



17. Install the distributor rotor onto the distributor shaft.
18. Install the distributor cap onto the distributor housing.
19. Install the two screws that hold the distributor cap to the distributor housing.

Tighten
Tighten the screws to 1.7 N·m (15 lb in).