Ignition Lock Cylinder Coding: Notes

Tools Required: 

J 41340 Ignition Lock Holding Fixture

1. Remove the ignition lock cylinder core from the ignition lock cylinder housing.
   1. Insert the key into the ignition lock cylinder.
   2. Rotate the lock cylinder core to START.
   3. Press the lock cylinder core retainer located in the end of the ignition lock cylinder.
   4. Pull the ignition lock cylinder core out of the lock cylinder housing using the key.
2. Pry the tumbler spring retainer out of the ignition lock cylinder core using a small flat-bladed tool.
3. Remove all of the tumbler springs.
IMPORTANT: Be careful to observe and record each tumbler and it's relative position in the lock cylinder core as the tumblers are removed.
4. Remove all of the tumblers by rotating the lock cylinder so that the tumbler slots are facing down.
5. Hold the lock cylinder core close to a flat surface.
6. Pull the lock cylinder core side bar out with your fingers. It may be necessary to tap the lock cylinder on a hard surface to remove all of the tumblers.
7. Determine the tumbler numbers and their respective positions.
   1. Place the tip of the key directly over the tip of the illustrated key.
   2. Inspect that the diagram outlines the key.
   3. Starting with position 1, the open end of the lock cylinder, find and record the lowest level tumbler number that is visible.
   4. Repeat the previous step for positions 2-10.
Fig 1: Tumbler Numbers & Positions
Courtesy of GENERAL MOTORS CORP.
8. Starting with position 1, insert the tumblers (4) into their corresponding slots in the coded order.
9. Using your fingers, pull out the side bar (3) until the tumblers fall completely into the lock cylinder core.
10. Insert one tumbler spring (2) above each tumbler (4).
11. Lubricate the tumblers using Superlube® GM P/N 12346241 or equivalent.
12. Insert the spring retainer (1) prongs into their respective slots in the lock cylinder core.
Fig 2: Installing Tumblers
Courtesy of GENERAL MOTORS CORP.
13. Press the retainer (1) down until the retainer is fully seated in the lock cylinder core.
Fig 3: Inserting Lock Retainer
Courtesy of GENERAL MOTORS CORP.
14. Inspect for proper tumbler installation:
    1. Hold the spring retainer (2) in position.
    2. Insert the key (1) into the lock cylinder. The side bar (3) should drop down to the level of the lock cylinder core. If the side bar does NOT drop down to the level of the lock cylinder core, proceed to step 2.
Fig 4: Inspecting Tumbler
Courtesy of GENERAL MOTORS CORP.
15. Remove the key from the lock cylinder core.
16. Secure the lock cylinder in the J 41340.
    1. Inspect that the spring retainer is facing up and positioned directly under the punch slots.
    2. Insert the lock cylinder completely into the J 41340 until the lock cylinder bezel contacts the J 41340.
    3. Tighten the J 41340 holding screw.
Fig 5: Securing Lock Cylinder Into J 41340
Courtesy of GENERAL MOTORS CORP.
17. Stake the bezel end of the spring retainer:
    1. Hold the flat side of the punch, part of J 41340 squarely against the face of the lock cylinder bezel.
    2. Stake the lock cylinder metal over the spring retainer prong.
Fig 6: Staking Spring Retainer
Courtesy of GENERAL MOTORS CORP.
18. Stake the opposite end of the spring retainer:
    1. Remove the J 41340 punch.
    2. Rotate the J 41340 punch 180 degrees.
    3. Hold the J 41340 punch squarely against the end of the punch slot on J 41340.
    4. Stake the lock cylinder metal over the spring retainer prong.
Fig 7: Staking Opposite Spring Retainer
Courtesy of GENERAL MOTORS CORP.
19. Loosen the J 41340 holding screw.
20. Remove the lock cylinder from the J 41340.
21. Inspect that the spring retainer is properly staked. Repeat staking as needed.
22. Lubricate the lock cylinder core retainer slot.
23. Insert the following parts into the lock cylinder core retainer slot:
    • The lock cylinder retainer spring (2)
    • The lock cylinder retainer (3)
Fig 8: Lubricating Lock Cylinder Retainer & Retainer Spring
Courtesy of GENERAL MOTORS CORP.
IMPORTANT: Use a paste type grease, not a spray, for the following step.
24. Lubricate the following parts with GM P/N 12345996 or equivalent:
    • The lock cylinder housing detent pins (1)
    • The lock cylinder retainer (3)
25. Orientate the lock cylinder retainer to the tapered notch in the lock cylinder housing.
26. Insert the ignition lock cylinder into the ignition lock cylinder housing.
27. Inspect for proper ignition lock cylinder rotation using the key.