Chevrolet 10 Series 1967, Service Manual

Page: 7 / 605

GENERAL INFORMATION 0-5
Lock cylinders are furnished for service uncoded, this
necessitates the coding of these replacement lock cyl­
inders.
The side bar type lock (fig. 24) is used for the ignition
and doors. To protect owners, truck lock manufacturers
stamp the lock numbers on the lock core, shaft, etc.,
where they will not show until lock is removed.
TUMBLERS
o) C 3
(prvvvvvj)
SPRING RETAINER
Fig . 24 - Side Bar Lock
In addition, when a lock cylinder requires replacement
the lock code number may be obtained either from the
key, if available, or from old lock cylinder which is being
replaced.
Once the code number of the lock is obtained look up
this number in a key cutting book.
All side bar locks furnished to the field by the Parts
Department are uncoded, that is, they are furnished with­
out tumblers, springs or spring retainers, these parts
are serviced separately. The tumblers come in five dif­
ferent depths, indicated by numbers.
The side bar locks have six tumbler positions, and in
looking up the cutting code, the following may be used as
an example. After key code number is determined, either
from key or from number stamped on lock cylinder refer
to your code book and record the key cutting information
as follows:
Key of Lock Key Cutting
Code Number Code Numerical
0 V 1 1
Cutting or Tumbler
position from head
of lock
545431
123456
NOTE: Key blanks used for ignition and door
locks are stamped with an "A".
The number that is written above the cutting or tumbler
position indicates each different tumbler which is to be
dropped into each tumbler slot of the lock.
In cases where a code book is not available, the dia­
gram shown on Figure 25 may be used to determine the
tumblers required to assemble an uncoded lock cylinder.
1. Lay the key on the diagram (fig. 25) with bottom of
key flush with edge of the drawing, head and point
carefully lined up.
2. Read the code in numbers 12345 from the head of key
to the end from positions 1 to
6
inclusive. As each
depth is determined write that number in the blank
space provided above the position numbers (1-2-3-4-
5-6).
3. With key properly lined up on diagram, all cuts that
show in the first section are to be marked "
1
".
4. Cuts that fall in the first black section, mark "2”.
5. Cuts that fall in the first white section, mark "3".
6
. Cuts that fall in second black section, mark "4".
7. Cuts that fall in the second white section, mark "5".
After the numbers have been determined and written
above the cutting positions the lock cylinder should be
assembled as follows.
Lock Cylinder Assembly—Refer to Figure 26
1. Hold cylinder with head of cylinder away and starting
at the head of the cylinder, insert the tumblers in
their proper slots in the order called for by the
code, ribbed side toward you and long point down.
2. After all tumblers are in place, check for correct­
ness with the code. Then press tumblers down with
one finger.
3. Insert one tumbler spring in the space provided
above each tumbler.
CAUTION: If the springs are tangled, do not
pull them apart—unscrew them.
Fig. 2 6 - Assembling Lock C ylin d er
CHEVROLET TRUCK SERVICE M ANUAL