Cadillac 60 Series 1963 Shop Manual page 78

POWER STEERING
5-19
3. Check pitman shaft for excessive wear or
for broken spring as follows:
a. Clamp pitman shaft in a vise.
b. Using Torque Wrench, J-7754, and a 7/32
inch Allen socket, measure the torque required
to turn the adjuster screw, Fig. 5-32. Torque
reading should be between 1-15 inch-pounds. If
reading is not within this range, the pitman shaft
must be replaced
e. Rack-Piston and Worm Assembly
Disassembly
1. Remove return guide clamp screws and re-
move clamp. )
A
2. Place assembly on a clean cloth and remove
ball return guides and Arbor, J-7539. -Make sure
all 22 balls are caught on the cloth.
Inspection
1. Inspect worm and rack-piston grooves and
all of the balls for excessive wear or scoring.
If either worm or rack-piston needs replacing,
both must be replaced as a matched assembly.
NOTE: Service replacement balls are avail-
able in different sizes as described in this Note
under "Assembly".
2. Inspect ball return guides, making sure that
the ends where balls enter and leave the guides
are not damaged.
3. Inspect lower thrust bearing and races for
wear, pitting, scoring or cracking. If any of these
conditions are found, replace thrust bearing and
races, and check worm.
4. Inspect rack-piston teeth for abnormal wear
or scoring. Inspect rack-piston O.D. for abnormal
wear, scoring, or burrs.
5. Visually inspect piston ring; if damaged,
remove ring and back-up O-ring seal and discard.
4. Insert worm into end of rack-piston, from
end opposite piston ring, until worm is against
rack-piston shoulder.
5. Load 16 balls into guide hole nearest piston
ring while slowly rotating worm counterclockwise
to feed balls through circuit. Alternate black
balls with white balls throughout the circuit.
6. Apply a liberal amount of petrolatum to one
ball return guide and install the 6 remaining balls
into guide. Place the other guide over the balls
and ball guide, and insert guides into guide holes
of rack piston. Make sure black ball in guide is
installed next to white ball in rack-piston. Guides
should fit loosely.
7. Place return guide clamp over guides and
secure with two screws and lockwashers. Tighten
screws to 12 foot-pounds.
8. Worm groove is ground with a high point in
the center. When rack-piston passes over this
high point, a preload of 1 to 4 inch-pounds should
be obtained. To measure preload of worm and
rack-piston ball assembly, proceed as follows:
a. Clamp rack-piston in a bench vise with soft
jaws, with worm shaft pointing up. Do not distort
rack-piston by tightening too heavily.
b. Place valve assembly on worm, engaging
worm drive pins.
c. Rotate worm until it extends 1-1/4 inches
from rack-piston to thrust bearing face. This is
center position.
d. Place Torque Wrench, J-7754, with a 3/4
inch 12-point socket on stub shaft, Fig. 5-33 and
rotate wrench through an arc of approximately
60° in both directions several times, then take a
torque reading. Highest average reading obtained
with worm rotating should be between 1 and 4
inch-pounds.
e. If reading is below 1 inch-pound, a new set
of balls must be installed upon reassembly.
Service replacement balls are available in sizes
listed in the following chart:
Assembly
1. Thoroughly clean the parts
them with power steering fluid.
and lubricate
2. Lubricate new back-up O-ring seal, if neces-
sary, with power steering fluid and install in
piston ring groove on rack-piston. Do not allow
seal to become twisted.
3. Install new piston
groove over O-ring seal.
ring, if necessary, in
Size Code
7
8
9
10
Mean Dia.
.28125
.28133
.28141
.28149
Size Range of Ball
.28120 - .28130
.28128 - .28138
.28136 - .28146
.28144 - .28154
Note the ball size stamped on the rack-piston and
install the next size larger balls to increase the
preload.