CLUTCH AND TRANSMISSIONS 7-33
from rolling. The pointer on the indicator quadrant
should line up properly with the range indicators in all
ranges.
OIL LEAKS
Before attempting to correct an oil leak, the actual
source of the leak must be determined. In many cases
the source of the leak can be deceiving due to "wind flow1 f
around the engine and transmission.
The suspected area should be wiped clean of all oil
before inspecting for the source of the leak. Red dye is
used in the transmission oil at the assembly plant and
will indicate if the oil leak is from the transmission.
The use of a "black light"* to identify the oil at the
source of leak is also helpful. Comparing the oil from
the leak to that on the engine or transmission dip stick
(when viewed by black light) will determine the source
of the leak.
Oil leaks around the engine and transmission are gen-
erally carried toward the rear of the car by the air
stream. For example, a transmission "oil filter tube
to case leak" will sometimes appear as a leak at the
rear of the transmission. In determining the source of
an oil leak it is most helpful to keep the engine running.
The mating surfaces of servo cover, converter housing,
transmission case and transmission case extension
should be carefully examined for signs of leakage. The
vacuum modulator must also be checked to insure that
the diaphragm has not ruptured as this would allow trans-
mission oil to be drawn into the intake manifold. Us-
ually, the exhaust will be excessively smoky if the
diaphragm ruptures due to the transmission oil added to
the combustion. The transmission case extension rear
oil seal should also be checked. All test plugs should be
checked to make sure that they are tight and that there
is no sign of leakage at these points. The converter
underpan should also be removed. Any appreciable quan-
tity of oil in this area would indicate leakage at the pump
square seal ring, pump seal assembly, or pump bolt
sealing washers.
BASIC PRESSURE CHECKS
Four basic pressure checks are used for diagnosis and
operational checks for the Aluminum Powerglide trans-
mission. All checks should be made only after thoroughly
warming up the transmission.
• Wide Open Throttle Upshift Pressure.
• Idle Pressure in "Drive" Range.
• Manual "Low" Range Pressure.
• "Drive" Range Overrun (Coast) Pressure.
It is not recommended that stall tests be conducted
which would result in engine vacuum falling below 10" Hg.
Pressure gauge hose connections should be made at
the low servo apply (main line) test point (fig. 14PG).
Run the gauge line into the driving compartment by
pushing aside the mast jacket seal. The line out of the
way of the drivers feet and connect to pressure gauge
J-21867.
• Wide Open Throttle Upshift Pressure Check
Refer to the pressure check chart for upshift pressure
SERVO APPLY
PRESSURE
Fig.
14PG - Pressure Test Plug
points as indicated on the lower servo apply (main line)
gauge.
• Idle Pressure in "Drive" Range
In addition tp the oil pressure gauges, a vacuum gauge
is needed for this check.
With the parking brake applied and the shift selector
lever in "Drive", low servo apply (main line) pressure
should be as shown on the pressure check chart.
If pressures are not within these ranges, the following
items should be checked for oil circuit leakage:
1.
Pressure regulator valve stuck.
2.
Vacuum modulator valve stuck.
3.
Hydraulic modulator valve stuck.
4.
Leak at low servo piston ring (between ring and
bore).
5.
Leak at low servo piston rod (between rod and bore).
6. Leak at valve body to case gasket.
7.
Leak at valve body gaskets.
8. Front pump clearances.
9. Check passages in transmission case for porosity.
• Manual "Low" Range Pressure Check
Connect a tachometer, apply the parking brake, place
the selector lever in "Low" range, and adjust the engine
speed to 1000 rpm with the car stationary.
Low servo apply (main line) pressure should be as
shown on the pressure check chart.
Pressures not within this range can indicate the fol-
lowing possibilities:
1.
Partially plugged oil suction screen.
2.
Broken or damaged ring low servo.
CHEVROLET CHASSIS SERVICE MANUAL
CLUTCH AND TRANSMISSIONS 7-36
TURBO HYDRA-MATIC TRANSMISSION
INDEX
Page
General Description . . , . 7-36
Maintenance and Adjustments . 7-37
Transmission Fluid 7-37
Fluid Level Indicator 7-37
Shift Control Linkage Adjustment ........... 7-37
Neutral Safety Switch Adjustment 7-37
Draining and Refilling Transmission . . . 7-37
Pressure Regulator Valve 7-38
Control Valve Body . 7-39
Governor ..'.... 7-40
Modulator and Modulator Valve 7-40
Parking Linkage . . 7-40
Page
Rear Seal -. 7-40
Other Service Operations . . 7-40
Transmission Replacement 7-40
Turbo Hydra-Matic Diagnosis Procedure. ......... 7-41
Sequence . ; ; 7-41
Oil Level and Condition Check 7-41
Manual Linkage 7-41
Oil Leaks .' 7-41
Case Porosity - Repair ................ 7-42
Oil Pressure Check 7-42
Transmission Shift Points 7-42
Special Tools 7-43
GENERAL DESCRIPTION
The Turbo Hydra-Matic transmission is a fully auto-
matic unit consisting primarily of a 3-element hydraulic
torque converter and a compound planetary gear set.
Three multiple-disc clutches, one sprag unit, one roller
clutch and two bands provide the friction elements re-
quired to obtain the desired function of the compound
planetary gear set.
The torque converter couples the engine to the plane-
tary gears through oil and provides hydraulic torque
multiplication when required. The compound planetary
gear set produces three forward speeds and reverse.
The
3-
element torque converter consists of a pump or
driving member, a turbine or driven member, and a
stator assembly. The stator is mounted on a one-way
roller clutch which will allow the stator to turn clock-
wise but not counter-clockwise.
The torque converter housing is filled with oil and
is attached to the engine crankshaft by a flex plate and
always rotates at engine speed. The converter pump is
an integral part of the converter housing, therefore the
pump blades, rotating at engine speed, set the oil within
the converter into motion and direct it to the turbine,
causing the turbine to rotate.
As the oil passes through the turbine it is traveling in
such a direction that if it were not re-directed by the
stator it would hit the rear of the converter pump blades
and impede its pumping action. So at low turbine speeds,
the oil is re-directed by the stator to the converter pump
in such a manner that it actually assists the converter
pump to deliver power or multiply engine torque.
As turbine speed increases, the direction of the oil
leaving the turbine changes and flows against the rear
side of the stator vanes in a clockwise direction. Since
the stator is now impeding the smooth flow of oil, its
roller clutch releases and it revolves freely on its shaft.
Once the stator becomes inactive, there is no further
multiplication of engine torque within the converter. At
this point, the converter is merely acting as a fluid
coupling as both the converter pump and turbine are
being driven at approximately the same speed - or at a
one-to-one ratio.
A hydraulic system pressurized by a gear type pump
provides the working pressure required to operate the
friction elements and automatic controls.
External control connections to transmission are:
Manual Linkage
Engine Vacuum
12 Volt Electrical
Signal
To select the desired op-
erating range.
To operate a vacuum mod-
ulator unit.
To operate an electrical
detent solenoid.
A vacuum modulator is used to automatically sense
any change in the torque input to the transmission. The
vacuum, modulator transmits this signal to the pressure
regulator for line pressure control, to the 1-2 accumula-
tor valve, and to the shift valves so that all torque re-
quirements of the transmission are met and smooth
shifts are obtained at all throttle openings.
The detent solenoid is activated by an alectric switch
on the carburetor. When the throttle is fully opened, the
switch on the carburetor is closed, activating the detent
solenoid and. causing the transmission to downshift at
speeds below approximately 70 MPH.
The selector quadrant has six selector positions: P,R,
N,D,
L2,L1.
P.
*
- Park position positively locks the output shaft to
the transmission case by means of a locking pawl
to prevent the vehicle from rolling in either di-
rection. The engine may be started in Park
position.
R. - Reverse enables the vehicle to be operated in a
reverse direction.
N.
- Neutral position enables the engine to be started
and run without driving the vehicle.
D,
- Drive Range is used for all normal driving condi-
tions and maximum economy. Drive Range has
three gear ratios, from the starting ratio to
direct drive. Detent downshifts are available by
depressing the accelerator to the floor.
L2.
- L2 Range has the same starting ratio as Drive
Range, but prevents the transmission from shift-
ing above second speed to retain second speed
acceleration when extra performance is desired.
L2 Range can also be used for engine braking.
L2 Range can be selected at any vehicle speed,
and the transmission will shift to second gear and
remain in second until the vehicle speed or the
throttle are changed to obtain first gear operation
in the same manner as in D Range.
CHIVROLET CHASSIS SERVICE MANUAL
CLUTCH AND TRANSMISSIONS 7-41
CAUTION: Use converter holding ToolJ-5384
when lowering transmission or keep rear of
transmission lower than front so as not to lose
converter.
The installation of the transmission is the reverse of
the removal.
TURBO HYDRA-MATIC DIAGNOSIS PROCEDURE
Accurate diagnosis of transmission problems begins
with a thorough understanding of normal transmission
operation. In particular, knowing which units are in-
volved in the various speeds or shifts so that the specific
units or circuits involved in the problem can be isolated
and investigated further. Analytical diagnosis will pro-
tect the technician from come backs and certainly will
improve owner satisfaction.
An important and often overlooked aspect of diagnosis
is finding out specifically what the customer is com-
plaining of. For this purpose a short ride with the cus-
tomer will often prove beneficial. It may be found that
the condition the customer wants corrected is standard
and should not be altered.
The following sequence, based on field experience, pro-
vides the desired information quickly and in most cases
actually corrects the malfunction without requiring the
removal of the transmission. Details of the items listed
in this sequence are covered further in the text.
SEQUENCE FOR TURBO HYDRA-MATIC
DIAGNOSIS PROCEDURE
1.
Check oil level and condition.
2.
Check and correct detent switch.
3.
Check and correct vacuum line and fittings.
4.
Check and correct manual linkage.
OIL LEVEL AND CONDITION CHECK
Always check the oil level before road testing. Oil
must be visible on dip stick prior to operating the ve-
hicle. Erratic shifting, pump noise, or other malfunc-
tions can in some cases be traced to improper oil level.
Oil level should be checked with the selector lever in
the Park (P) position, engine running, and the vehicle on
level pavement.
Fluid level should be to the FULL mark with the trans-
mission at normal operating temperature (170°-190°
F.).
With warm fluid (room temperature), the level should be
at or slightly below the ADD mark.
If oil level was low, refer to Oil Leaks.
The condition of the oil is often an indication of whether
the transmission should be removed from the vehicle, or
to make further tests. When checking oil level, a burned
smell and discoloration indicate burned clutches or bands
and the transmission will have to be removed.
MANUAL LINKAGE
Manual linkage adjustment and the associated neutral
safety switch are important from a safety standpoint
The neutral safety switch should be adjusted so that the
engine will start in the Park and Neutral positions only.
With the selector lever in the Park position, the park-
ing pawl should freely engage and prevent the vehicle
from rolling. The pointer on the indicator quadrant
should line up properly with the range indicators in all
ranges.
OIL LEAKS
Before attempting to correct an oil leak, the actual
source of the leak must be determined. In many cases,
the source of the leak can be deceiving due to "wind flow"
around the engine and transmission.
The suspected area should be wiped clean of all oil be-
fore inspecting for the source of the leak. Red dye is
used in the transmission oil at the assembly plant and
will indicate if the oil leak is from the transmission.
. The use of a "black light"* to identify the oil at the
source of leak is also helpful. Comparing the oil from
the leak to that on the engine or transmission dip stick
(when viewed by black light) will determine the source
of the leak.
Oil leaks around the engine and transmission are gen-
erally carried toward the rear of the car by the air
stream. For example, a transmission "oil filler tube to
case leak" will sometimes appear as a leak at the rear of
the transmission. In determining the source of an oil
leak it is most helpful to keep the engine running.
POSSIBLE POINTS OF OIL LEAKS
• 1. TRANSMISSION OIL PAN LEAK
a. Attaching bolts not correctly torqued.
b.
Improperly installed or damaged pan gasket.
c. Oil pan gasket mounting face not flat.
2.
REAR EXTENSION LEAK
a. Attaching bolts not correctly torqued.
b.
Rear seal assembly — damaged or improperly
installed.
c. Gasket seal — (extension to case) damaged or
improperly installed.
d. Porous casting.
3.
CASE LEAK
a. Filler pipe "O" ring seal damaged or missing;
misposition of filler pipe bracket to engine —
"loading" one side of
"O"
ring.
b.
Modulator assembly "O" ring seal
—
damaged or
improperly installed.
c. Governor cover, gasket and bolts — damaged,
loose; case face leak.
d. Speedo gear
—
"O" ring damaged.
e. Manual shaft seal — damaged, improperly in-
stalled.
f. line pressure tap plug — stripped, shy sealer
compound.
g. Parking pawl shaft cup plug
—
damaged, improp-
erly installed.
h. Vent pipe (refer to Item 5).
i. Porous case.
4.
FRONT END LEAK
a. Front seal - damaged (check converter neck for
nicks,
etc., also for pump bushing moved for-
ward);
garter spring missing from pump to con-
verter seaL
b.
Pump attaching bolts and seals
—
damaged, miss-
ing, bolts loose.
CHEVROLET a
SERVICE
CLUTCH AND TRANSMISSIONS 7-42
c. Converter
—•
leak in weld.
d. Pump tfO" ring seal — damaged. (Also check
pump groove and case bore.)
e. Porous casting (pump or case).
5. OIL COMES OUT VENT PIPE
a. Transmission over-filled.
b.
Water in oil.
c. Pump to case gasket mispositioned.
d. Foreign material between pump and case, or be-
tween pump cover and body.
e. Case — porous, pump face improperly machined.
f. Pump — shy of stock on mounting faces, porous
casting.
CASE POROSITY-REPAIR
Transmission leaks caused by aluminum case porosity
have been successfully repaired with the transmission in
the vehicle by using the following procedure.
1.
Road test and bring the transmission to operating
temperature.
2.
Raise the car and, with the engine running, locate the
source of the oil leak. Check for leaks in all operat-
ing positions.
NOTE:
The use of a mirror will be helpful in
finding leaks.
3.
Shut off engine and thoroughly clean area with a sol-
vent and air dry.
4.
Using the instruction of the manufacturer, mix a suf-
ficient amount of epoxy cement, part #1360016, to
make the repair.
5. While the transmission is still hot, apply the epoxy
to the area, making certain that the area is fully
covered.
6. Allow epoxy cement to dry for three hours and re-
test for leaks, as outlined in Steps 1 and 2.
OIL PRESSURE CHECK
With Car Stationary
Transmission oil pressure gauge and engine tachome-
ter should be connected and the oil pressures should
check as follows:
1.
Pressures indicated below are at 0 output speed with
the vacuum modulator tube disconnected and with en-
gine at 1200 rpm.
Approximate
Altitude of Check
(Ft. above sea level)
0
2,000
4,000
6,000
8,000
10,000
12,000
14,000
Drive
Neutral
Park
150
150
145
138
132
126
121
116
LI
or
L2
150
150
150
150'
150
150
150
150
Reverse
244
233
222
212
203
194
186
178
2.
Pressures indicated below are with the vacuum tube
connected for normal modulator operation, and with
the engine at 1200 rpm.
NOTE:
Pressures are not significantly affected
by altitude or barometric pressure when the
vacuum tube is connected.
Drive, Neutral, Park Ll or L2 Reverse
70 150 107
TURBO HYDRA-MATIC SHIFT POINTS
Engine
Throttle
Position
Closed
Detent
Touch
Thru
Detent
V327 (L30)
2.73 Axle - 8.25 - 14 Tire
•1-2 Up
7.7-11.5
36.4-50.1
2-1 Dn
10.9-6.9
74.8-91.4
2-3 Up
17.5-22.6
85.1-67.6
3-2 Dn
19.5-14.6
43.3-26.6
Chevrolet Models
(MPH)
V396 (L35)
2.73 Axle - 8.25 - 14 Tire
1-2 Up
8.0-12.9
38.4-55.9
2-1 Dn
10.3-4.3
45.6-25.2
2-3 Up
17.2-27.8
/
74.8-91.7
3-2 Dn
18.3-12.6
83.7-65.0
V427 (L36)
2.73 Axle - 8.25 - 14 Tire
1-2 Up
8.6-12,6
44.1-58.5
2-1 Dn
1-1.7-6.6
45.8-27.2
2-3 Up
17.5-30.7
81.1-99.4
3-2 Dn
18.9-14.3
92.6-73.4
Chevelle Models (MPH)
Throttle
Position
Closed
Detent
Touch
Thru
Detent
V396(L34)
3.07 Axle - F70 - 14 Tire
1-2 Up
7.4-10.9
38.1-50.4
2-1 Dn
9.6-5.7
39.5-23.5
2-3 Up
15.1-26.4
69.9-85.7
3-2 Dn
16.3-12.4
79.8-63.3
CHEVROLET CHASSIS SERVICE MANUAL
CLUTCH AND TRANSMISSIONS 7-45
23
Fig.
5T - Aluminum Powerglide Special Tools
1. J-9506
2.
J-3289-01
3.
J-9549
4.
J-21867
5.
J-4264
6. J-3387
7.
J-9539
8. J-6839
9. J-9546
10.
J-7782
11.
J-5133
12.
J-4599
13.
J-9542
14.
J-9557
Holding Fixture Adapters
Holding Fixture (Use with J-3289-20 Base)
Converter Safety Strap
Transmission Pressure Gauge and Hose
Oil Filler Tube and Funnel
Pilot Stud Set
Front Pump Puller Bolts (Use with weights
from Slide Hammers J-6585)
Front Pump Seal Driver
Clutch Drum Bushing Remover and Installer
Clutch Spring Compressor Adapter Plate
Clutch Spring Compressor
Planet Pinion Assembly Tool Set
Reverse Piston Spring Compressor
Transmission Case Rear Bushing Remover and
Installer and Rear Pump Bushing Remover
15.
J-7079
16.
J-6582
17.
J-9543
18.
J-5778
19.
J-5154
20.
J-5403
21.
J-5814
22.
J-5853
23.
J-8039
24.
J-21848
J-8001
J-5492
J-6585
J-6585-3
J-9534
Handle
Rear Pump Bushing Installer
Vacuum
Modu
lator Wrench
Extension Bushing Remover and Installer
Extension Oil Seal Installer
Snap Ring Pliers
Speedometer Drive Gear Remover and
Installer
Torque Wrench
Snap Ring Pliers
Low Band Adjusting Tool
Dial Indicator (Not Illustrated)
Dial Indicator Support Strap (Not Illustrated)
Slide Hammers (Not Illustrated)
Slide Hammer Adapters (Not Illustrated)
Bushing Remover (Not Illustrated)
CHEVROLET CHASSIS SERVICE MANUAL
STEERING
9-33
POWER STEERING
INDEX
Page
General Description
. 9-33
Maintenance
and
Adjustments
9-33
Bleeding Hydraulic System
9-33
Fluid Level
. 9-33
Adjustments
. 9-34
Power Steering Gear
. . 9-34
Pump Belt Tension
9-34
Hydraulic System Checks
9-34
Component Replacement
and
Repairs
. 9-35
Power Steering Pump.
. 9-35
Power Steering Gear
9-36
Control Valve
and
Adapter Assembly
9.35
Power Cylinder
9.37
Power Steering Hoses
9.39
GENERAL DESCRIPTION
Two types
of
power steering
are
used
for 1967.
One
is
the conventional linkage type
for
Chevy
n and
Corvette
vehicles
and the
other
is the
integral gear type
for
Chevrolet, Chevelle,
and
Camaro.
For
both types
the
hydraulic pressure
is
provided
by an
engine-driven vane-
type pump.
On
the
Chevy
n and
Corvette linkage type power steer-
ing, hydraulic pressure
is
delivered through
a
hose from
the pump
to a
valve which senses
the
requirement
for
power assistance
and
supplies
the
power cylinder
ac-
cordingly.
The
steering gear used with this power steer-
ing
is the
same basic unit used
on
manually steered
vehicles;
it is
serviced
as
outlined
in the
manual steering
part
of
this section except
for
adjustment, which
is
covered
in the
following pages.
The
steering linkage also
is serviced the same
as
manual counterparts.
The Chevrolet, Chevelle
and
Camaro integral gear type
power steering
has the
hydraulic pressure delivered
from
the
pump through two hoses
to the
steering gear.
In
the power steering gear
the
steering shaft, hydraulic
valve, worm, and rack-piston
nut are all in
line making
a
compact
and
space saving assembly.
All oil
passages
are
internal within
the
gear except
the
pressure
and
return
hoses.
The steering gear
is a
recirculating ball system
in
which steel balls
act as a
rolling thread between
the
steering worm
and
rack-piston
nut. The
rack-piston
nut
is
all one
piece
and is
geared
to the
sector
of
the piston
shaft.
The
valve
is
contained
in the
gear housing elimi-
nating
the
need
of
bolts
or
seals
to
attach
a
separate
valve housing.
The valve
is an
open-center, rotary-type three
way
valve.
The
spool
is
held
in
neutral position by means
of a
torsion
bar. The
spool
is
attached
by
means
of
the stub
shaft
to one end of the
torsion
bar
and
to the
valve body
on
the
other
end.
Twisting
of the
torsion bar allows
the
spool
to
move
in
relation
to the
valve body thereby oper-
ating
the
valve.
MAINTENANCE
AND
ADJUSTMENTS
BLEEDING HYDRAULIC SYSTEM
1.
Fill
oil
reservoir
to
proper level and
let oil
remain
undistrubed
for at
least two minutes.
2.
Start engine
and run
only
for
about
two
seconds.
3.
Add
oil if
necessary.
4.
Repeat above procedure until
oil
level remains
con-
stant after running engine.
5. Raise front
end of
vehicle
so
that wheels
are off
the
ground.
6. Increase engine speed
to
approximately
1500 rpm.
7. Turn
the
wheels
(off
ground) right
and
left, lightly
contacting
the
wheel stops.
8. Add
oil if
necessary.
9. Lower
the car and
turn wheels right and left
on the
ground.
10.
Check
oil
level and refill
as
required.
11.
If oil is
extremely foamy, allow vehicle
to
stand
a
few minutes with engine
off and
repeat above
procedure.
,
a.
Check belt tightness
and
check
for a
bent
or
loose
pulley. (Pulley should
not
wobble with engine
running.)
b.
Check
to
make sure hoses
are not
touching
any
other parts
of the car,
particularly sheet metal.
c. Check
oil
level, filling
to
proper level
if
neces-
sary, following operations
1
through
10.
This
step
and
Step
"D" are
extremely important
as
low
oil
level and/or
air in the oil are the
most
frequent causes
of
objectionable pump noise.
d. Check
the
presence
of air in the oil. If air is
present, attempt
to
bleed system
as
described
in
operations
1
through
10. If it
becomes obvious
that
the
pump will
not
bleed after
a few
trials,
proceed
as
outlined under Hydraulic System
Checks.
FLUID
LEVEL
1.
Check
oil
level
in the
reservoir
by
checking
the dip
stick when
oil is at
operating temperature.
On
Chevelle models equipped with remote reservoir,
the reservoir should
be
maintained approximately
3/4 full when
oil is at
operating temperature.
2.
Fill,
if
necessary,
to
proper level with
GM
Power
Steering Fluid
or, if
this
is not
available, automatic
CHEVROLET CHASSIS SERVICE MANUAL
STEERING 9-34
Fig.
64-Over Center Adjustment
transmission fluid "Type A" bearing the mark
"AQ-ATF" followed by a number and the suffix
letter "A".
ADJUSTMENTS
POWER STEERING GEAR
Chevrolet, Chevelle, and Camaro
The over-center adjustment (fig. 64) is the only power
steering gear adjustment which can be made on the car.
However, in order to make this adjustment, it is also
necessary to check the combined ball and thrust bearing
preload.
If the vehicle is equipped with a tilt column it will be
necessary to disconnect the steering coupling to obtain a
torque reading of the column. This torque should then be
subtracted from any reading taken on the gear.
1.
Disconnect the pitman arm from the relay rod.
2.
Loosen the pitman shaft adjusting screw loeknut and
thread the adjusting screw out to the limit of its
travel through the side cover. '. •
3.
Disconnect steering column harness at chassis wir-
ing connector plug.
4.
Remove horn button.
5.
Turn the steering wheel through its full travel, then
locate the wheel at its center of travel.
6. Gheck the combined ball and thrust bearing preload
with an inch-pound torque wrench on the steering
shaft nut by rotating through the center of travel
(approximately 1/4 turn in each direction). Note the
highest reading.
7.
Tighten the pitman shaft adjusting screw and check
torque at steering shaft nut until over center preload
and total steering gear preload falls within speci-
fications. Refer to torque specifications at rear of
manual for correct torque values.
8. Install horn button. Connect steering column harness
at wiring connector plug.
Chevy II and Corvette
The steering gear used with power steering is adjusted
in the same manner as the manual steering gear.
PUMP BELT TENSION
1.
Loosen nut on pivot bolt and pump brace adjusting
nut.
CAUTION: Do not move pump by prying against
reservoir or by pulling on filler neck.
2.
Move pump, with belt in place until belt is tensioned
to specifications as indicated by Tool J-7316 (Fig-.
65).
3.
Tighten pump brace adjusting nut. Then tighten pivot
bolt nut.
HYDRAULIC SYSTEM CHECKS
The following procedure outlines methods to identify
and isolate power steering hydraulic circuit difficulties.
This test is divided into two parts. Test number one
provides means of determining whether power steering
system hydraulic parts are actually faulty. If test number
one results in readings indicating faulty hydraulic opera-
tion, test number two will identify the faulty part. Be-
fore performing hydraulic circuit test, carefully check
belt tension and condition of driving pulley. Strand
tension of belt should be 125 lbs. on new belts and 75 lbs.
on old belts, as indicated by Tool J-7316 (Fig. 65).
Test Number One—Oil Circuit Open
Engine must be at normal operating temperature. In-
flate front, tires to correct pressure. All tests are made
with engine idling, so adjust engine idle speed to correct
specifications listed in Section 6 and proceed as follows:
a. With engine not running, disconnect flexible pres-
sure line from pump and install Tool J-5176 as
Fig.
65— Checking Belt Tension with Tool J-7316
CHEVROLET CHASSIS SERVICE MANUAL
STEERING 9-35
Fig.
66—Power Steering Diagnosis
shown in Figure 66. Gauge must be between shut-
off valve and pump. Open shut-off valve,
b.
Remove filler cap from pump reservoir and check
fluid level. Fill pump reservoir to full mark on
dip stick. Start engine and, holding steering
wheel against stop, check connections at Tool
J-5176 for leakage. Bleed system as outlined
under Maintenance and Adjustments. Insert ther-
mometer (Tool J-5421) in reservoir filler open-
ing. Move steering wheel from stop to stop
several times until thermometer indicates that
hydraulic fluid in reservoir has reached tempera-
ture of 150° to 170°F.
CAUTION: To prevent scrubbing flat spots on
tires,
do not turn steering wheel more than five
times without rolling car to change tire-to-floor
contact area.
c. Hold steering wheel against a stop momentarily
and read pressure gauge. If the maximum pres-
sure is below specifications, a faulty hydraulic
circuit is indicated. To determine which part is
faulty, proceed with test number two.
Test Number Two—Oil Circuit Closed
a. Slowly turn shut-off valve on J-5176 to closed
position and read pressure indicated on gauge.
Quickly reopen valve to avoid pump damage, if
indicated pressure is less than specification,
pump output is below requirement and pump may
be considered faulty. If pressure indicated is
within specifications, it may be safely assumed
that the external hoses, connections, valve and
adapter or steering gear is at fault.
NOTE:
If pump proves faulty in test number
two,
test should be repeated after pump is re-
paired and installed in vehicle. This will provide
a means of checking the repairs made to the
pump and the condition of the steering gear or
valve and adapter which may also be faulty.
COMPONENT REPLACEMENT AND REPAIRS
POWER STEERING PUMP
Removal (Fig. 67)
1.
Disconnect hoses at pump. When hoses are discon-
nected, secure ends in raised position to prevent
drainage of oil. Cap or tape the ends of the hoses to
prevent entrance of dirt.
NOTE:
Chevelle with 396 engine uses a remote
reservoir. It is necessary to disconnect the
reservoir to pump hose before removing the
pump.
Hold a 1 qt. container under the reservoir
when the hose is removed to catch the fluid.
2.
Install two caps at pump fittings to prevent drainage
of oil from pump.
3.
Remove pump belt.
4.
On Corvette with 427 engine, loosen alternator ad-
justment and remove pump to alternator belt.
5. Remove pump from attaching parts and remove pump
from vehicle.
NOTE:
On Chevrolet and Chevy II equipped with
283 and 327 engine it may be necessary to re-
move pump brace.
6. Remove drive pulley attaching nut.
7. Remove pulley from shaft with Tool J-21239 (for
stamped pulleys) or Tool J-8433-1 with J-8433-2
adapter (for cast iron pulleys). Do not hammer
pulley off shaft as this will damage the pump.
Fig.
67—Power Steering Pump Mounting
CHEVROLET CHASSIS SERVICE MANUAL