Spare Wheel Hoist Lock Cylinder Coding

Courtesy of GENERAL MOTORS COMPANY

This end gate locks uses five cut positions and tumblers numbered 1 through 4 (R and L). The tumbler positions are staggered from side to side, three on one side and two on the other. The lock cylinder tumblers are not snap-in/self-retaining.

1. Hold the cylinder component (1) as shown in picture.
2. Insert one tumbler spring (2) into each of the three spring cavities on cylinder (1).
3. The first loaded tumbler (3) will correspond to the first cut position, which will be first number in the key code. Install the first tumbler in the slot nearest the head of lock cylinder. Install the remaining tumblers following the key code into slots at key cut positions 3 and 5.
4. Check the correct loading by holding the tumblers in position and fully inserting the key into cylinder assembly. All tumblers should be flush with the outside diameter of the cylinder assembly body.
5. Rotate the cylinder component (1) so the opposite tumbler slots are facing upward and than remove the key. Keep in mind it will be required to hold all tumblers down before removing the key to keep them from falling out.
6. Insert one tumbler spring (2) into each of the two remaining spring cavities.
7. The first tumbler (3) to be loaded will correspond to the second key cut position, the second number in the key code. Install the tumbler in the slot nearest the head of lock cylinder. Install the remaining tumblers following the key code into the slots at key cut positions 4.
8. Repeat step 4 to confirm all tumblers are properly assembled/located.
9. Lightly lubricate the tumbler surface and the small detent recess on the side of the cylinder assembly using the provided grease.
10. Hold down the already inserted tumblers so they do not fall off, remove the key and insert the two provided shutter springs (4).
11. Insert the shutter (5) in direction as shown in the picture until you feel and hear the snap in of the two shutter legs into the cylinder (1).
12. Insert back the key all the way in into the lock assembly and proceed to insert this sub-assy into case (6).
13. Using the key, rotate sub-assy into case until a proper fit is achieved. Try to align the tumblers with upper slot on top of case (6), than proceed to remove the key (cylinder assembly won't be able to fall off now).
14. Locate down the bolt spring (9) on the axis shown in picture.
15. Now proceed to insert the bolt (10) down and above spring (9) on same axis as shown in picture.
16. From the back or tail of the lock assembly, insert both of the seals as shown on the visual aid. From back to front of the assembly first insert seal (7), and then after seal (8).
17. As a final inspection, insert back the key all the way in to confirm the cylinder can freely rotate and can actuate the lock bolt as it should. This must be able to move up and down.
18. Finally locate cap (11) on top or front of the lock assembly. For this cap to be properly secured a manual press has to be used.