Page 1077 of 2189

Pressure Control
Low assist at higher speeds:
WhensteeringresistanceIsIow,suchaswhendrivingathighspeeds,orwhendrivingstraightahead,theinputshaftis
near or in the neutral position, so there is little or no fiow ro any of the power cylinder orifices. Most oI the feed pressure
fromthepumpisbypassedtothereservoir.Becauseofthis,thepressurestaysthesameinbothsidesofthepowercy||n-
der, resulting in low or no asslst
VALVE From PUMP
SECTION A-A
RETURN PASSAGElTo RESERVOIRI
POWER CYLINDER
STEERING GEARBOX
High assist at lower speeds:
When steering resistance is high. such as when driving at low speeds' or when turning the wheel wirh the vehicle
stopped,thedifference|nang|ecreatedbetweentheinputshaftandtheVa|veopensthef|uidpassageononeside,and
c|osesthefluidpassageontheotherside,ateachpairoforifices'Thef|uidpressureincreasesinthesideo|thepower
cy|inder|edbythe|argerf|uidpassage'Thisincreasedpressurepushesontherackpiston,a|lowingthesteeringwhee|to
be turned with light effort. on the other side of the power cylinder, the return passage opens allowing the steering tluid to
returnthroUghtheinputshafttothereservoir'Thef|uidpassagestothepowercy|inderautomatica||ychangeins|ze,
increasing as the steering resrstance increases. In other words, the passages become larger and power assist increases
when the steering effort would normally be high, (for example' when parking or making low speed turns)' and the pas-
sagesbecomesma||erandpowerassistdecreaseswhenthesteeringeffortwou|dnorma||ybe|ow,(forexamp|e,when
driving at high speeds or straight ahead).
FLUIO PASSAGE TO
POWER CYLINDER
/t=\\a!-4,))
=YjJ
RESERVOIR
SECTION A-A
l'
{High fluid Pressure}
Page 1078 of 2189

Troubleshooting
General Troubleshooting
Check the following before you begin:. Has the suspension been modified in a way that would affect steering?. Are tire sizes, tire variety and air pressure correct?. lsthe steering wheel original equipment or equivalent?. lsthe powersteering pump belt properlyadiusted?
. ls steeringfluid reservoirfilledto proper level?. ls the engine idle speed correct and steady?
Hard Steering (Check the powor assist. se€ page 17-3o. lfthe torce is over 29 N (3.0 kgf, 6.6lbo, Procede with this troubleshootinq.)
Abnormallluid pressure
{fluid pressureis too high)
Faulty valve body unit
Relief pres-sure too low
Abnormal
Faulty llow control valve(Replace the pump es anassembly)
Ch€ck the feed snd return circuit lin€s ano nosebetw6€n the gearbox and pump for clogging andd€lormation.
Normal line and hose
Check the pump fluid pressure(soe page 17-34).l/easure steady-state tluid pres-s!re while idling with the bothvalves tully open.It should be 1.500 kPa (15 kgf/cmr,213 psi) or below.
Normal
Check th€ flow control vslve (see page 17-42).. Chock the valvo lor smooth movement in the hous-ing.. Check the reliefvalve for leaks.
Check the pump fluid pressure
{see page 17-34).Measure pump relief pressurewhile idling with the pressure con-trol valve Iully closed.It should be 6,400 - 7,400 kPa (65 -
75 kgflcm,,920 - 1,070 psi)
Normal relisf pressure
17-22
Go to page 17-23Faulty pump assembly
Page 1079 of 2189
I
AbnormalDeformed
Faulty cylinder lines
Adiustment OK
Faulty valve body unit
Normal
IICompair the steering to another alike
vehicle.
/
Check the force required to turn
the wheel (see Page 17 30i
Start the engine and measure the
force required to turn the wheel
to the right and left. Difference of
the lorce required to turn the
wheel to the right and to the Ieft
should be 2.9 N 10 3 kgf, 0.7 lbf)
or below.
Check for bent rack shaft
Check rack guide adiustment (see
page 17-33).
(cont'd)
17 -23
1,,
Page 1081 of 2189

/
Uneven or rough steering
Steering wheel kicks back
during wide t!rns.
ll,
)
Adjust the rac* guide (see page 17-3).
lf the problem is not corrected bY
adjusting the rack guide, replace
the gearbox.
Adiust the belt tension. Feplace the
belt, il necessary (see Page 17 32).
lfthe engine stalls when the wheel
is turned while car is stopped or
moving at low speed, adjust the
idle spe€d (see section 11)
ldle speed low or erratic.
Check power sleering fluid level lf
the level is excessively low, check
lor leaks in the system. Add lluid
to the specified level.
Air in reservoir, or check Powersteering Iluid level.
lf ltuid level is OK, check O-rings
and seals on both ends of thepump inlet hose, and the P/Spump housing mating surfaces
and the pumP shaft oil seal for
suction leaks. RePlace Parts as
nocessary.
Adjust the belt tension (see Page17 32)or replace belt.Pump belt sliPPing on PLrlleY(pump stops momentarilY)
Check if pump press{rre is normal
and the gauge needle travel is 500
kPa (5 kgl/cm?, 7l Psi) or less.
Chock the flow control valve if the
needle travel exceeds 500 kPa (5
kgflcm' , 71 Psi). l{ the flow control
valve is normal, replace the PumPas an assemoly.
Install the power steering pressure
gauge, Close the Pressure contrcl
valve fully and m6ssure the PumPpressure {s€e page 17-34}.
17 -25,
Page 1082 of 2189

Troubleshooting
Noise and Vibration
NOTE; Pump noise in first 2 - 3 minutes after starting in cold weather is normal.
Humming
Rattle or chattering
Humming due to pulsation of fluid is normal, particularlv when the wheel isturned with the vehicle stooDed.
lf equipped with automatic trans-mission, the hum could be thetorque conveater or pump noise.
Confirm by temporarily removingthe pump belt.
High-pressure line touching theframe.Reposition the line.
Loose steering shaft connector,tie-rod. or balljoint.Check and tighten, or replacepaats as necessary.
Column shaft wobbling.Replace the column assembly.
Check the rack guide tor properadjustment (see page 17,33).Adiusi, if necess€ry.
Rattling sound and feeling when turning the steering wheel raght and left with theengine OFF is normal.
Pump noise, though not loud. trom the valve body unit can be heard whon turn-ing the steering wheel right or left. This is normat.
CAUTION: When imp€sting, do not hold the steering wheet a[ the way tothe right or the left.
17-26
Page 1084 of 2189

Troubleshooting
Fluid Leaks
Check the gearbox assembly for oil leaks carefully. Oil can leak out of various points. depending on location of thefaulty oil seals/seal rings. Check the following before removing the gearbox from the frame_
Steering GearboxLeaking from the oil seal on thetop of the valve housing.Replace the valve oil seal fromthe valve housing.
Leaking from cylinder end intoleft tie rod boot.Replace the valve oil seal tromthe pinion shaft.
Replace the cylinder end seal onthe gear housing side.
Leaking lrom cylinder end intoright tie-rod boot.Replace the cylinder end seal onthe cylinder end side.
Leaking lrom the shaft upper endsectron or pin engagement sec,tion ol the pinion shaft.Replace the valve body unit.
Tighten the connector. lf it's stillleakinO, replace the Iine, cylinderor valve housing unit.
Leaking from cylinder line A or Bconnections {at tlare nut}.
Leaking caused by a damagedcylinde.line A or B.Replace cvljnder line A or B.
Leaking from feed line and returnline ioint fitting on the valve bodyunit (at flare nut).
Tighten the connector. ll it's stillleaking, replace the line,,oint fit,ting or valv6 housing.
17-2a
Page 1090 of 2189

lnspection and Adjustment
Pump Pressure Check
Check the fluid pressure as follows to determine
whether the trouble is in the pump or gearbox.
NOTE: First check the power steering fluid level andpump belt tension.
CAUTION: Disconnect the high pr$sure hos€ with care
so as not lo spill the power sieering tluid on tha frame
and other parts.
1. Disconnect the outlet line from the Dumo outlet fit-
ting, then installthe P/S joint adaptor (pump) on the
Dumo outlet.
2. Connect the P/S joint adaptor (hose) to the power
steering pressure gauge, then connect the outlet
hose to the adaptor.
3. Install the power steering pressure gauge to the P/Sjoint adaptor (pump) as shown.
ourlEr HosE FnrNo ,t"ll lrilu"ott
P/S JOINT ADAPTOB IHOSEI07RAK - S0i10l2rol07RAK- 50{{)120
P/S PRESSURE GAUGE07406 - 001000Aor07406 - 0010001
4. Open the shut-off valve fully.
5. Open the pressure control valve fully.
17-34
(Pa.t of tooll11 N.m11.1 kgt m, 8 lbf.ftl
PRESSURECONTROL VALVE
SHUT.OFFVALVE
PUMP OUTLETFITTING
6 x 1.0 mm BOLTlPart of tool)11 N.m11.1 kgf m, 8 lbtftl
7.
Start the engine and let it idle.
Turn the steering wheel from lock-to-lock several
times to warm the fluid to operating temperature.
Measure steady-state fluid pressure while idling. If
the pump is in good condition, the gauge should
read less than 1500 kPa (15 kgf/cmr, 213 psi).
lf it reads high, check the outlet line or valve body
unit (see General Troubleshooting 17-22).
Close the pressure control valve, then close the
shut-off valve gradually until the pressure gauge
needle is stable. Read the oressure.
lmmediately open the pressure control valve fully.
GAUTION: Do not keep lhe prossure control valve
clos€d more then 5 soconds or the pump could be
damagod by over-heating.
lf the pump is in good condition, the gauge should
read at least 6,400 - 7,400 kPa (65 - 75 kgflcm,, 920 -
1,070 psi). A low reading means pump output is too
low for full assist. Repair or replace the pump,
9.
P/S PBESSURE GAUGE07{16 -@1@OA
oi
SI{UT.OFF VALVE
Page 1095 of 2189

Power Steering Hoses, Lines
Fluid Leakage Inspection
HOSES and LINES
. Inspect hoses for damage, leaks, interference or
twisting.
. Inspect tluid lines for damage, rusting and leakage.
. Inspect for leaks at hose and line joints and connec-
tions.
POWER STEERINGswtTcH12 N.m {1.2 kgt.m,9lbt.ft}
CYLINDER HOUSING-to.CYLINDER LINES28 N.m (2.7 kgf.m, 20 lbf.ft)
VALVE BODY UNIT-to-CYLINDER LINES'17 N.m {1.712 tbl.ftl
VALVE BODY UNIT-Io-FEED/RETURN LINES
Feed line: 14 x '1.5 mm llare nut
37 N.m {3.8 kgJ.m, 27 lbf'tt)
Return Line Joint 16 x 1.5 mm flare nut
28 N m 12.7 kgf.m,20 lbtft)
HOSE CLAMP:
. Position the hose clamps at the points indicated (b) in
the drawing above.
. Slide the hose over the line until it contacts the stop.
8()07Check for leaks.
OUTLET HOSE11 N.m
G€AR8OX and VALVE BODY UNITCheck for leaks at the mating surfaceand flare nut connections,
tbt(Double Ring Typei
CAUTION: Check all clamps for deterioration or delor-
mation; replace with the clamps new ones il necessary.
(1.1 kgf.m,8
PUMP ASSEMBLYCheck for leaks at the pump
seal, inlet and outlet fiftings.
Replacement
NOTE:
. Connect each hose to the corresponding pipe securely
until it contacts the stop on the line. Install the clamp
or adiustable clamp at the specified distance from the
hose end as shown.
. Add the power steering fluid to the specified level on
the reservoir and check for leaks.
ADJUSTABLE HOSE CLAMP:
. Position the adiustable hose clamps at the points
indicated (a) in the drawing above.
. Slide the hose over the line until it contacts the stop.
2.5 - 5.5 mm{0.01 - 0.22 in)2.0 - 4.0 mm(0.08 - 0.16 in)
2.5 - 5.5 mm(0.01- 0.22 in)1.,
17-39