1995 ACURA TL steering

Steering — Sectio n 1 7
Suspensio n — Sectio n 1 8
Brake s — Sectio n 1 9
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Engine Removal/Installation

Removal (cont'd)

7. Remove the battery cables from the under-hood fuse/

relay box.

BATTERY

CABLES

8.

9.
UNDER-HOOD

FUSE/RELAY BOX

Disconnect the engine wire harness connector on

the right (passenger's) side of the engine compart-

ment.

Remove the battery cable from the under-hood ABS

fuse/relay box.

BATTERY

CABLE

ENGINE WIRE

HARNESS

UNDER-HOOD ABS

FUSE/RELAY BOX
10. Remove the intake air duct and vacuum hose.

INTAKE AIR

DUCT

11.
VACUUM

HOSE

Remove the adjusting bolt, locknut and mounting

bolt, then remove the power steering (P/S) pump

belt and pump.

MOUNTING BOLT

10 x
1.25
mm

49 N-m (5.0 kgf-m, 36 Ibf-ft)

ADJUSTING

BOLT

P/S PUMP

BELT

LOCKNUT

8 x
1.25
mm

22 N-m (2.2 kgf-m,

16 Ibf-ft)ProCarManuals.com

Component Location s
Index
NOTE :
• I f a n intac t airba g assembl y ha s bee n remove d fro m a scrappe d vehicl e o r ha s bee n foun d defectiv e o r damage d dur -
in g transit , storag e o r service , i t shoul d b e deploye d (se e sectio n 24 ).
• Befor e removin g th e steerin g gearbox , remov e th e driver' s airba g assembl y an d steerin g wheel .
• Afte r installin g th e steerin g gearbox , chec k th e whee l alignmen t an d adjus t i f necessary .
SR S component s ar e locate d in thi s area . Revie w th e SR S componen t locations , precautions , an d procedure s in th e SR S
( sectio n 24 ) befor e performin g repair s o r service .
STEERIN G WHEE LRemoval , pag e 17-2 7
Disassembly/Reassembly , pag e 17-2 8
Installation , pag e 17-2 9
RESERVOI RFluid Replacement , 17-2 4
VALVE BOD Y UNI T
Overhaul , pag e 17-5 2
POWE R STEERIN G SPEE D SENSO R
Replacement , pag e 17-2 1
STEERING COLUM N
Removal , pag e 17-3 1
Inspection , pag e 17-3 3
Installation , pag e 17-3 4IGNITIO N SWITC HSee sectio n 2 3
POWE R STEERIN G PUM P
Pum p Bel t Inspection , pag e 17-2 3
Pum p Bel t Adjustment , pag e 17-2 3
Pum p Pressur e Check , pag e 17-2 5
Removal , pag e 17-3 7
Disassembly , pag e 17-3 7
Reassembly , pag e 17-4 2
Installation , pag e 17-4 6
STEERIN G GEARBO XRack Guid e Adjustment , pag e 17-2 4
Removal , pag e 17-4 7
Disassembly , pag e 17-4 9
Reassembly , pag e 17-5 6
Installation , pag e 17-6 6 TIE-RO
D EN D BAL L JOIN T
Bal l Join t Boo t Replacement , pag e 17-6 9
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System Descriptio n
This powe r steerin g syste m is speed-sensitive . It s mai n component s ar e a mechanica l spee d sensor , a rotar y valve-typ e
gearbox, an d a constan t volume , vane-typ e pump . Th e syste m regulate s th e powe r assis t accordin g to vehicl e speed , roa d
conditions , an d drivin g style . Th e amoun t o f powe r assis t change s linearl y fro m hig h assist , whe n drivin g a t lo w speed s o r
parking , t o lo w assist , whe n drivin g a t hig h speeds .
Fluid Flo w Diagra m
The flui d volum e fro m th e pump , whic h i s drive n b y th e cran k pulley , i s regulate d b y th e flo w contro l valv e buil t int o th e
pump . Th e regulate d flui d i s fe d t o th e valv e bod y uni t locate d outsid e th e pinio n shaf t o f th e steerin g gearbox . Th e flui d i s
regulate d t o th e prope r pressur e b y th e valve s i n th e valv e bod y uni t an d b y th e powe r steerin g spee d senso r befor e it
flow s t o th e powe r cylinder . Th e directio n o f th e flo w is determine d b y th e rotar y valve . Th e flui d the n returns to th e reser -
voi r throug h th e retur n passag e an d i s fe d t o th e pum p again .
To RESERVOI R
VALVE BOD Y UNI T
TORSIO N BA R
INPU T SHAF T
VALVE (SLEEVE )
RIGHT CYLINDE R PASSAG E
POWE R CYLINDE R
Steering Gearbo xLOW SPEE D FEE D PASSAG E
The steerin g gearbo x i s th e rack-and-pinio n type . Th e valv e bod y uni t consist s o f th e valv e bod y unit , wher e th e flui d pas -
sag e i s regulate d b y th e flui d pressure , an d th e assis t contro l valv e uni t whic h regulate s th e flui d passag e t o th e rotar y
valv e accordin g t o vehicl e speed .
ASSIST CONTRO L VALV E UNI T
STEERIN G RAC K VALV
E BOD Y UNI T
ToRESERVOI R
From PUM P
POWE R CYLINDE RCYLINDE
R LINE S ASSIS
T CONTRO L VALV E UNI T
PUM P
To POWE R STEERIN G
SPEE D SENSO R
PUM
P OUTLE T
HIGH-PRESSUR E
HIGH SPEE D
FEE D PASSAG E
POWER STEERIN G
SPEE D SENSO R
RESERVOI R
LEFT CYLINDE R
PASSAG E
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Steering Pum p
Constructio n
The pum p is a vane-typ e incorporatin g a flo w contro l valv e (wit h a n integrate d relie f valve ) an d i s drive n b y a POLY-V-bel t
fro m th e cran k pulley . Th e pum p feature s 1 0 vanes . Eac h van e perform s tw o intake/discharg e operation s fo r ever y rota -
tio n o f th e rotor . Thi s mean s tha t th e hydrauli c flui d pressur e puls e become s extremel y smal l durin g discharge .
DRIVE SHAF TFLOW CONTRO L VALV E
CAM RIN G
INLE T POR TVANE
ROTO R
Operatio n
The belt-drive n pulle y rotate s th e roto r throug h th e driv e shaft . A s th e roto r rotates , th e hydrauli c pressur e i s applie d t o
th e van e chambe r o f th e roto r an d th e vane s wil l rotat e whil e bein g pushe d ont o th e inne r circumferenc e o f th e ca m ring .
Th e inne r circumferenc e o f th e ca m rin g ha s a n extende d portio n wit h respec t t o th e cente r o f th e shaft , s o th e vane s
mov e downwar d i n th e axia l directio n a s th e roto r rotates . A s a resul t o f thi s rolle r movement , th e interna l volum e o f th e
van e chambe r wil l change , resultin g i n flui d intak e an d discharge .
START O F FLUI D INTAKE :FLUID INTAKE :FLUID MOVEMENT :FLUID DISCHARGE :
DISCHARGE POR T
The vane s ar e pushe d ont othe inne r circumferenc e o f th ecam ring .
The volum e o f th e van e cham -ber increase s s o tha t flui d i ssucke d in .
Th e sucked-i n flui d move stoward th e discharg e port .As th e vane s retur n t o th ethei r origina l positio n o n th einne r side , th e volum e o f th evan e chambe r decrease s s othe flui d i s discharge d fro mthe discharg e port .
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System Descriptio n
Steering Pum p (cont'd )
Flow Contro l
Fluid fro m th e pum p run s throug h a meterin g orific e to
th e valv e bod y unit . Thi s create s a pressur e differenc e
betwee n th e pum p an d valv e bod y uni t side s o f th e ori -
fice. Whe n pressur e in th e pum p sid e is highe r tha n th e
forc e o f th e sprin g holdin g th e flo w contro l valv e closed ,
i t pushe s th e valv e dow n (open) , an d exces s flui d
return s t o th e pum p inlet . Th e combine d effec t o f th e
meterin g orific e an d th e flo w contro l valv e provide s a
relativel y constan t flo w o f flui d t o th e valv e bod y unit .
PUM P
FLO W CONTRO L
VALVE
RELIEF VALV E OPE N
DAMPIN G
ORIFICE
FLOW CONTRO L
VALV E
RELIE F VALV E BAL L
METERIN GORIFICE
To Valv e bod y Uni t
Pressur e Relie f
As pressur e o n th e valv e bod y uni t sid e build s up , i t
pushe s th e relie f valv e bal l (insid e th e flo w contro l
valve ) u p agains t it s spring , an d exces s flui d return s t o
th e pum p inlet . As the pressur e unde r th e flo w contro l
valv e drops , th e relie f valv e bal l i s close d b y it s spring ,
an d th e flo w contro l valv e i s force d dow n again , allow -
in g exces s flui d fro m th e pum p sid e t o retur n t o th e
inlet . Thi s flo w contro l valve-relie f valv e cylinde r keep s
pump outpu t pressur e betwee n 7,00 0 - 8,00 0 kP a (7 0 - 8 0
kgf/cm2, 99 5 - 1,13 8 psi) .
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One-way Valve (In Power Steering Speed

Sensor)

When the vehicle is moving at high speed, negative

pressure develops at the sensor inlet because the power

steering speed sensor is pumping faster than the fluid

can be supplied. To compensate for this, the outlet and

inlet ports are connected internally by a passage con-

taining a one-way valve that lets output fluid recirculate

to the inlet port to equalize pressure.

Driving at High Speed:

ONE-WAY VALVE
RESERVOIR

ROTORS
Relief Valve (In Power Steering Speed Sensor)

When the vehicle is moving in reverse, the power steer-

ing speed sensor also turns backward and pumps fluid

in the opposite direction. To avoid building up pressure

in the reaction chambers that would increase steering

effort while driving in reverse, the inlet and outlet-ports

are connected by a second internal passage containing a

relief valve that allows the fluid to recirculate.

Driving in Reverse:

RESERVOIR

RELIEF VALVEProCarManuals.com

Valve Bod y Uni t
The rotar y valv e bod y uni t ha s tw o valves , a lo w spee d valv e an d a hig h spee d valve , whic h ca n b e identifie d b y th e cham -
fer width.
CHAMFE R O F HIG H SPEE D VALVE : LARG E
HIG H SPEE D VALV E
SLEEV E
CHAMFE R O F LO W SPEE D VALVE : SMAL L
LO W SPEE D VALV E
The openin g are a (th e ga p betwee n th e inpu t shaf t an d th e sleeve ) o f th e tw o valve s change s wit h th e displacemen t angl e
(angl e ga p betwee n th e inpu t shaf t an d th e sleeve ) produce d durin g steering . I n othe r words , th e valv e openin g are a
change s accordin g t o th e intensit y o f th e roa d reactio n (steerin g torque) .
Whe n th e vehicl e i s stopped , th e powe r steerin g spee d senso r function s operat e onl y th e lo w spee d valve .
Becaus e th e lo w spee d valv e ha s th e smal l chamfe r an d thereb y th e smal l openin g area , hig h flui d pressur e ca n b e fe d t o
th e powe r cylinde r wit h th e smal l displacemen t angl e (smal l steerin g torque) , resultin g i n ligh t steerin g (hig h assist) .
FLOW: 0 (ZERO ) OPENIN
G ARE A
HIG H SPEE D
VALV E
SMALL A
t STO P
DISPLACEMEN T ANGL E
When drivin g th e vehicle , th e flui d i s applie d t o th e hig h spee d valve , too , a s th e vehicl e spee d senso r functions . Becaus e
th e hig h spee d valv e ha s a larg e chamfe r an d thereb y th e larg e openin g area , th e openin g are a o f th e tw o valve s i s com -
pounded , eve n thoug h th e displacemen t angl e i s th e sam e a s whe n th e vehicl e i s stopped .
Therefore , th e flui d pressur e i s no t generate d unles s th e displacemen t angl e i s larg e (larg e steerin g torque) , resultin g i n
moderatel y heav y steerin g (mediu m assist) .
From ASSIS T CONTRO L VALV E
HIG H SPEE D
VALV E OPENIN
G ARE A
LARG EAREA
MIDDL EAREA
SMAL LAREA
At STO P
PRESSUR E MIDDL
E SPEE D RANG EPRESSUR E
DISPLACEMEN T ANGL E
T
o RIGH T CYLINDE R
LO
W SPEE D VALV E
HIGH-PRESSUR
E
Fro
m LEF T CYLINDE R HIG
H SPEE D RANG E
PRESSUR E
Fro
m LEF T CYLINDE R
HIGH-PRESSUR E
LO W SPEE D VALV E
T o RIGH T CYLINDE R
INPUT SHAF T
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