ACURA TL 1995 Service Repair Manual

Brake Hoses/Lines

Inspection ('97 - '98 models)

1. Inspect the brake hoses for damage, deterioration, leaks, interference and twisting.

2. Check the brake lines for damage, rusting and leakage. Also check for bent brake lines.

3. Check for leaks at hose and line joints and connections, and retighten if necessary.

4. Check the master cylinder and ABS modulator unit for damage and leakage.

CAUTION: Replace the brake hose clip whenever the brake hose is serviced.

MASTER CYLINDER-to-BRAKE LINE

19 N-m (1.9 kgf-m, 14 Ibf-ft)

ABS MODULATOR UNIT-to-BRAKE LINE

19 N-m (1.9 kgf-m, 14 Ibf-ft)
BRAKE HOSE-to-CALIPER

(BANJO BOLT)

34 N-m (3.5 kgf-m, 25 Ibf-ft)

BLEED SCREW

9 N-m (0.9 kgf-m, 6.5 Ibf-ft)

BRAKE LINE-to-BRAKE HOSE

15 N-m (1.5 kgf-m, 11 Ibf-ft)

BRAKE LINE-to-4-WAY JOINT

19 N-m (1.9 kgf-m, 14 Ibf-ft)

BRAKE HOSE-to-CALIPER

(BANJO BOLT)

34 N-m (3.5 kgf-m, 25 Ibf-ft)

BLEED SCREW

9 N-m (0.9 kgf-m, 6.5 Ibf-ft)
BRAKE LINE-to-BRAKE HOSE

15 N-m (1.5 kgf-m, 11 Ibf-ft)ProCarManuals.com

Hose Replacemen t
CAUTION:
• Befor e reassembling , chec k tha t al l part s ar e fre e o f
dus t an d othe r foreig n particles .
• Replac e part s wit h ne w one s wheneve r specifie d t o
do so .
• Do no t spil l brak e flui d o n th e vehicle ; i t ma y damag e
the paint ; i f brak e flui d doe s contac t th e paint , was h
it of f immediatel y wit h water .
1. Replac e th e brak e hos e i f th e hos e i s twisted , crack -
ed , o r i f i t leaks .
2 . Disconnec t th e brak e hos e fro m th e brak e lin e usin g
a 1 0 m m flar e nu t wrench .
FLARE NU T
WRENC H
BRAK E LIN E
BRAK E HOS E
3. Remov e an d discar d th e brak e hos e cli p fro m th e
brak e hose .
BRAK E HOS E CLI P
Replace .
BRAKE HOS E MOUNTING ,BOLT (8 mm) ,
BRAK E HOS E
BRAK E HOS E
MOUNTIN G BOL T
BANJ O BOL T
4. Remov e th e banj o bolt , an d disconnec t th e brak e
hos e fro m th e caliper . 5
. Instal l
the brak e hos e o n th e knuckl e an d dampe r
first, the n connec t th e brak e hos e to th e calipe r wit h
the banj o bol t an d ne w sealin g washers .
BRAKE HOS E MOUNTIN G
BOL T ( 8 mm )
22 N- m(2.2 kgf-m , 16 Ibf-ft )
BRAK E HOS E MOUNTIN GBOLT9.8 N- m (1. 0 kgf-m , 7 Ibf-ft);
BRAK E HOS E
BANJ O BOL T
34 N- m(3.5 kgf-m , 25 Ibf-ft )
6. Instal l a ne w brak e hos e cli p o n th e brak e hose .
15 N- m(1.5 kgf-m , 11 Ibf-ft )
BRAK E HOS E CLI PReplace .
7. Connec t the brak e lin e t o th e brak e hose .
8 . Afte r installin g th e brak e hose , blee d th e brak e sys -
te m (se e pag e 19-7 ).
9 . Perfor m th e followin g checks .
• Chec k th e brak e hos e an d lin e join t fo r leaks , an d
tighte n i f necessary .
• Chec k th e brak e hose s fo r interferenc e o r twist -
ing.
ProCarManuals.com

Parking Brake Cable

Inspection and Replacement

CAUTION: The parking brake cables must not be bent or distorted. This will lead to stiff operation and premature cable

failure.

CLEVIS PIN

CLIP

Replace.

BRACKET

PARKING BRAKE CABLE

Check for faulty movement.

PARKING BRAKE LEVER

Check for smooth

operation.

PARKING BRAKE SWITCH

(Sliding surface)

Disconnect the parking brake cable from the lever on the

caliper by removing the lock pin and clevis pin, and

remove the cable from the arm by removing the clip.

PARKING BRAKE CABLE

CLIP

Replace.
LEVER

CLEVIS PIN
LOCK PIN

Replace.

LOCK PIN
LOCK PIN

Replace.

ADJUSTING

NUT

EQUALIZERProCarManuals.com

Special Tool s
Ref. No.Too l Numbe r DescriptionQtyPag e Referenc e
07HAJ-SG0010Ao r
07HAJ-SG0010B
07PAZ-001010 0AL
B Checke r
SC S Servic e Connecto r
19-112
19-54
ProCarManuals.com

Illustrated Inde x
The accumulato r contain s high-pressur e nitroge n gas ; d o no t puncture , expos e to flame , o r attemp t t o dis -
assembl e th e accumulato r o r i t ma y explode ; sever e persona l injur y ma y result .
MODULATO R UNI T
AB S Functio n Test , pag e 19-11 2
Modulato r Functio n Check , pag e 19-11 4
Relievin g Syste m Pressure , pag e 19-11 5
Brak e Flui d Replacement , pag e 19-11 5
Removal/Installation , pag e 19-11 7
Wir e Harnes s Replacement , pag e 19-11 9
Pum p Moto r Replacement , pag e 19-11 9
Accumulato r Replacemen t an d Disposal , pag e 19-12 0
Reservoi r Replacement , pag e 19-12 0FAIL-SAF E RELAY SInspection , pag e 19-12 2
AB S CONTRO L UNI T
Replacement , pag e 19-12 1
REAR WHEE L SENSO RInspection , pag e 19-12 2
Replacement , pag e 19-12 3
ABS MOTO R RELA YInspection , pag e 19-12 2
FRON T WHEE L SENSO RInspection , pag e 19-12 2Replacement , pag e 19-12 3
ProCarManuals.com

Anti-lock Brake System (ABS)

Features/Construction

In a conventional brake system, if the brake pedal is depressed very hard, the wheels can lock before the vehicle comes to

a stop. In such a case, the stability of the vehicle is reduced if the rear wheels are locked, and maneuverability of the vehi-

cle is reduced if the front wheels are locked, creating an extremely unstable condition.

The Anti-lock Brake System (ABS) modulates the pressure of the brake fluid applied to each front caliper or both rear

calipers, thereby preventing the locking of the wheels, whenever the wheels are likely to be locked due to hard braking. It

then restores normal hydraulic pressure when there is no longer any possibility of wheel locking.

The ABS equipped on this car is compact, with its hydraulic control system incorporated into one modulator unit. It is a

3-channel anti-lock brake system that has individual control of the front wheels and common control ("select low") for the

rear wheels. "Select low" means that the rear wheel that would lock first (the one with the lowest resistance to lock-up)

determines anti-lock brake system activation for both rear wheels.

ABS CONTROL UNIT

GEAR PULSER

MASTER CYLINDER

MODULATOR UNIT

REAR WHEEL SENSOR

GEAR PULSER
FRONT WHEEL SENSOR

PART NAME

Gear pulser

Wheel sensor

ABS control unit

Modulator unit

Motor Relay

Fail-safe relay
MAJOR FUNCTION

Attached to the rotating part of the wheel and detects the wheel speed together with the

wheel sensor.

Generates pulse signal corresponding to the revolution of the gear pulser.

Controls the working of the anti-lock brake system by performing calculations based on the

signals from the individual wheel sensors and the individual switches.

• Adjusts the hydraulic pressure applied to each caliper on the basis of the signals received

from the ABS control unit.

• Pump, accumulator, solenoid valves, pressure switch and pistons are integrated in the mod-

ulator unit.

Controls the ABS pump motor's power supply according to the signal from the ABS control unit.

Cuts off the solenoid valve ground circuit when the fail-safe device is at work.ProCarManuals.com

Modulator Unit:

The modulator unit consists of the following sub-units. It adjusts the hydraulic pressure applied to each caliper on the

basis of the signals received from the ABS control unit.

• ABS pump and motor: Supplies high-pressure brake fluid to control the ABS operation.

• Accumulator: Stores the high-pressure brake fluid.

• Pressure switch: Detects the pressure in the accumulator and transmits signals to the ABS control unit.

• Solenoid valves: Switches the ABS high-pressure passage according to the signals from the ABS control unit.

• Pistons and related parts: Receives the high-pressure brake fluid, and controls pressure to the calipers accordingly.

MODULATOR UNIT

Motor and pump:

As the motor rotates, it drives the plunger-type ABS pump and raises the brake fluid pressure to approximately 25 MPa

(250 kgf/cm2, 3,600 psi). The eccentric bearing is attached to the motor shaft end; it contacts the plunger of the pump

plunger. The motor shaft's rotational motion is transmitted to the reciprocating motion Of the pump plunger.

When the plunger is pushed, the brake fluid in the plunger chamber is pressurized and fed to the accumulator, solenoid,

and piston, via the check valve. When the pressure in the accumulator exceeds 34 MPa (350 kgf/cm2, 5,000 psi), the relief

valve opens to release the excess brake fluid pressure to the reservoir, thereby protecting the system.

CHECK VALVE

(OUTLET)

RELIEF VALVE

To ACCUMULATOR,

SOLENOIDS, PISTONS
RESERVOIR

PUMP

CHECK VALVE

(INLET)

HIGH-PRESSURE CIRCUIT

ECCENTRIC BEARING
MOTOR

PLUNGER

CHAMBER

PLUNGERProCarManuals.com

Anti-lock Brake System (ABS)

Features/Construction (cont'd)

Accumulator:

The high-pressure brake fluid discharged from the pump

is fed to the solenoids and pistons, but the passages to

the solenoids and pistons are normally closed. Con-

sequently, the high-pressure brake fluid accumulates in

the accumulator.

The accumulator consists of two chambers separated by

a free piston; that is, the fluid chamber where the brake

fluid is accumulated, and the chamber filled with high-

pressure nitrogen gas to maintain the fluid at a given

pressure.

When the ABS operates, the constant high-pressure

brake fluid in the accumulator is supplied to the piston.
GAS CHAMBER

(FILLED WITH NITROGEN GAS)

FLUID CHAMBER O-RINGS

FREE PISTON
RELIEF PLUG

Pressure switch:

The pressure switch monitors the pressure accumula-

tion in the accumulator. When the pressure in the accu-

mulator rises, the Bourdon tube in the pressure switch

deforms outward, which in turn activates the micro-

switch by the force of the spring attached to the sensing

lever. When the pressure in the accumulator drops due

to ABS operation, the Bourdon tube moves in the oppo-

site direction, and the micro-switch is eventually turned

off.

The ABS control unit detects the fluid pressure in the

accumulator by the ON/OFF signals from the pressure

switch.
MICRO-SWITCH

SENSING LEVER

BOURDON TUBEProCarManuals.com

Piston/valve:

The piston/valve assembly consists of the piston, cut valve, and sleeve. There are four piston/valve assemblies in the mod-

ulator unit to control the brake fluid pressure to each caliper. The piston/valve assemblies for the rear brakes also serve as

proportioning control valves to prevent the rear wheels from locking if the ABS malfunctions or when the ABS is not acti-

vated.

Solenoid valves:

The modulator unit opens and closes the inlet and outlet solenoid valves, and shifts the ABS high-pressure passage

according to the signals from the ABS control unit. There are three solenoid valve assemblies, each containing an inlet

and outlet valve, in the modulator unit; one for each front wheel, and one for both rear wheels. The inlet valves are nor-

mally open (open when the coil is not energized), while the outlet valves are normally closed.

MODULATOR UNIT

RESERVOIR

To ABS CONTROL

UNIT

To RIGHT-FRONT

WHEEL

To LEFT-FRONT

WHEEL

PUMP MOTOR RELAY
From MASTER

CYLINDER

PRIMARY PISTON

From MASTER

CYLINDER

SECONDARY

PISTON

To LEFT-REAR

WHEEL

To RIGHT-

REAR WHEEL
MOTOR
PUMP

PISTON/VALVE
CUT

VALVE
PISTON
SLEEVE
SOLENOID VALVES (3 SETS)

RELIEF

VALVE

ACCUMULATOR

PRESSURE

SWITCHProCarManuals.com

Anti-lock Brake System (ABS)

Features/Construction (cont'd)

Wheel sensor:

The wheel sensor is a contactless type that detects the rotating speed of a wheel. It consists of a permanent magnet and

coil. When the gear pulsers attached to the rotating parts of each wheel turn, the magnetic flux around the coil in the

wheel sensor alternates, generating voltages with frequency in proportion to wheel rotating speed. These pulses are sent

to the ABS control unit, and the ABS control unit identifies the wheel speed.

WHEEL SENSOR

COIL PERMANENT MAGNET

at HIGH SPEED

at LOW SPEED

GEAR PULSER

GEAR PULSER

ABS control unit:

The ABS control unit consists of a main function, which controls the operation of the anti-lock brake system, and sub-func-

tion, which controls the pump motor and "self-diagnosis".

For safety, the main function consists of two systems, and the ABS control unit activates the solenoid valve only when the

outputs of the two systems agree with each other.

The main function section of the ABS control unit performs calculations on the basis of the signals from each wheel

sensor, and controls the operation of the anti-lock brake system by activating the solenoid valves in the modulator unit

for each front brake and for the two rear brakes. The ABS has individual control of the front wheels and common con-

trol ("Select low") for the rear wheels. "Select low" means that the rear wheel that would lock first (the one with the

lowest resistance to lock-up) determines the ABS activation for both rear wheels.

The sub-function section has the fail-safe function that monitors the system operation by inputting the brake switch,

parking brake switch and pressure switch signals, and stops the anti-lock brake system when it detects an abnormality

in the system. It also has a self-diagnosis function and the pump motor control function.

WHEEL SENSORS
ABS CONTROL UNIT

RIGHT-FRONT WHEEL

LEFT-FRONT WHEEL

RIGHT-REAR WHEEL

LEFT-REAR WHEEL

BRAKE SWITCH

PARKING BRAKE SWITCH
MAIN FUNCTION

• BASIC ABS

FUNCTION CONTROL

SUB-FUNCTION

• SELF-DIAGNOSIS FUNCTION

• FAIL-SAFE FUNCTION

• PUMP MOTOR CONTROL

PRESSURE SWITCH

PUMP MOTOR RELAY
MODULATOR UNIT

SOLENOID

SOLENOID

SOLENOID

FRONT FAIL - SAFE RELAY

REAR FAIL - SAFE RELAY

PUMP MOTORProCarManuals.com