F300-BR-Brake_System-Part1
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PART 1 - PART 2 - PART 3 - PART 4 - PART 5 - PART 6 - PART 7 - PART 8 - PART 9 - PART 10
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DAIHATSU
BRAKE
OUTLINE OF BRAKE SYSTEMS
PRECAUTION TROUBLE SHOOTING CHECK OF BRAKE SYSTEM BRAKE PEDAL FRONT BRAKE REAR BRAKE BRAKE MASTER CYLINDER BRAKE BOOSTER PARKING BRAKE
P & B VALVE (PROPORTIONING AND
BY-PASS VALVE)
SSTs (Speicial Senrioe Tool) SERVICE SPECIFICATIONS
TIGHTENING TORQUE
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OUTLINE OF BRAKE SYSTEMS
BRAKE LINE
The brake line comes in two kinds; one for the R.H.D. vehicles and the other for the L.H.D. vehicles.
On all models, the disc brake is provided at the front wheels, while the drum brake is installed at the rear
wheels. The front and rear brake systems are operated through a proponioning valve.
The brake pipe a iwo-winding copper tube. the inside of is treafed with Cu plating, while the
outside is treated with Cu-Zn plating and resin coating as anticorrosion treatment.
HE
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BRAKE
PEDALS
All the operating pedals, such as the clutch pedal. accelerator pedal and brake pedal, adopt a hanging type whose pedal fuicrum is provided at the pedal support located upward of each pedal.
Clutch pedal
Brake pedal
Pedal-related specifications
Remarks
Clutch 216 - 226
216 - 226
211 -221
Measured with dash board vertical wall as reference. Measured from dash board steel sheet with silencer turned
oven
150 7
Clutch
150
EFLequipped vehicle 55
60
<Accelerator peda|> Adjust in such a way that stopper bolt-to-pedal stopper clearance becomes 0 to 3 mm when throttle valve is opened fully.
Clulch 18 - 27
18-27
Pedal free travel
mm I Brake 1 _ 3
__ _f
Accelerator 1 - 5
1-5
<Brake peda!> with engine stopped, depress brake pedal strongly several times so that vacuum no longer exists inside brake booster. Measure iree travel by pushing pedal lightly with your finger.
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BRAKE
BRAKE BOOSTER 8: MASTER CYLINDER
The brake booster employs a direct acting brake booster having an 8-inch effective diameter in order that the pedal appiying force may be reduced during the braking and the braking performance may be improved. The master cylinder is an aluminum alloy-made tandem master cylinder located inside the engine compart
The reservoir adopts a sealed type incorporating a diaphragm. In this reservoir, the brake fluid is shut from
the atmosphere, thus preventing deterioration of the brake fluid and improving the reliability.
Front stroke
Lg! Front stroke
.
Brake booster
Diaphragm effective diameter W 7 77"
203
Effective stroke
31.5 or more
Jumping amount
Master cylinder
Stroke Fmm
18.5
Rear
11.5
Inner diameter
ITIITI
22.22
Reserve tank capachy cc Rea,
12
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OPERATION OF BRAKE BOOSTER Non-operating condition The air valve is buried against the control valve by means of the control valve spring. Therefore, the atmosphere that has passed through the air cleaner element is interrupted at the air valve and no air can enter into the variable pressure chamber. Moreover. the air valve is pulled to the right by the air valve spring, until it contacts the valve stopper key. Also. the booster piston is apart from the control valve (because of the section B). As a result, the negative pressure of the constant pressure chamber is applied through the passage A also to the variable pressure chamber. Consequently, the booster piston is pushed to the right by the tension ofthe piston return spring
Jumping condition When the brake pedal is depressed and the air valve spring tension is overtaken, the operating rod starts moving toward the Ielt side. Finally, the control valve becomes butted against the booster piston (see the section B), thus closing the negative pressure passage A. When the operating rod farther travels toward the left side, the control valve becomes apart from the air vaive. Consequently, the atmosphere that has passed through the air cleaner ele- ment is permitted to enter into the variable pressure chamber. In this way, the booster piston begins moving toward the left side, thereby generating a booster output. At this point. the reaction disc is compressed between the booster piston and the piston rod because of a gap which has been already provided between the air valve and the reaction disc. Then, the compressed reaction disc changes its shape ir: such a way that the gap between the air valve and the reaction disc may be filled with the reaction disc. As a result, no reaction force trom the master cylinder is transmitted to the air valve. until the reaction disc contacts the air valve. The booster output at this potnt is represented as the jumping amount.
(Negative pressure)
1 i f 'K-5
Piston relurn spring
Constant pressure chamber
Negative pressure passage A
Air valve
Section B
Control valve
Variable pressure chamber
(Negative pressure) Hoosier piston
(Negative pressure)
Piston return spring
Constant pressure chamber
Negative pressure passage A
Air valve
Sectrnn B
Reaction disc
Variable pressure
permitted to enter.)
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BRAKE
f
Operating condition The deformation of the reaction disc that was being com- pressed between the booster piston and the piston rod further progresses and the reaction disc eventually makes contact with the air valve. When the pedal applying force increases further from this con- dition and the operating rod travels larther toward the left, the air valve and control valve are held apart from each other, thus permitting the atmosphere to enter into the variable pressure chamber continually. Consequentiy, the power assist of the booster increases further and the hydraulic pressure of the master cylinder. too, continues to rise.
Holding condition When the force being applied to the operating rod (the pedal applying force) is kept at a constant value, soon the control valve and air valve are ciosed, thereby stopping the atmos- phere flow to the variable pressure chamber. As a result. the power assist of the booster piston becomes stabilized. When the pedal applying force and power assist become sta- bilized, the force being applied to the reaction disc also be- comes a constant value. Furthermore, the hydraulic pressure of the master cylinder becomes equal to the force which is transmitted from the reaction disc. This condition of equilibrium continues until any change in the pedal applying icrce occurs.
Piston rod
Constant pressure chamber (Negative pressure)
Air valve Emi
Control valve
g Atmosphere
Operating rod
Variable pressure chamber (Atmosphere |S permitted lo enter)
it
Booster piston
Constant pressure chamber (Negative pressure)
Reaction disc
L.
Variab\e pressure chamber (Negative pressure weaker than constant pressure chamber)
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Maximum power assist condition When the pedal applying force increases further, the variable pressure chamber eventually is filled with the atmosphere, thereby fully reaching tothe atmospheric pressure. At this point. the differential pressure that is applied to the booster piston reaches to the maximum value. In this way, the power assist of the booster also reaches its limit. Simultaneously, the movement of the control valve also is restricted. Consequently. a condition where the control valve is held closely against the booster piston (section B) is retained. If the pedal applying force is increased further from this condi- tion. this additional force is added to the reaction disc. As a result. the hydraulic pressure ofthe master cylinder also rises. corresponding to that additional portion of force,
Released condition As the pedal applying force decreases, the force equilibrium condition between the reaction disc and the air valve is lost, thereby pushing back the air valve toward the right side. Then, the air valve makes contact with the control valve, thus inter- rupting the atmosphere circuit from the air cleaner to the vari- able pressure chamber. Simultaneousiy, the control valve also moves toward the right side by the function of the air valve spring. Hence, the negative pressure of the constant pressure chem~ ber is new applied to the variable pressure chamber through the passage A. When the difference in pressure between the constant pressure chamber and the variable pressure chamber no longer exists because of the negative pressure supplied from the constant pressure chamber, the booster piston com- pletely returns io the original position owing to the tension of the piston return spring.
Q" Variable pressure chamber (Fu rl atmospheric pressure)
Reaction disc
Booster piston
Constant pressure chamber (Negative pressure)
Piston return spring Negawe pressure
passage A
Reaction disc
Airvalve
I‘.'.......,‘$\ rr
'
Variable pressure chamber
(Negative pressure) Booster piston
Control valve
Air valve spring
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BBAKE
In case where no negaiive pressure is available: In instances where no negative pressure is applied to the booster owing to some troubles. both the constant pressure chamber and variable pressure chamber remain under the atmospheric pressure condition. thereby offering no power as- sist. Nevertheless, when the brake pedal is depressed and the operating rod travels toward the left side. a force is applied to the piston rod from the air valve through the reaction disc. At this time. the air valve also pushes the valve stopper key, which is inserted into the booster piston, tothe left. Then. the force overcomes the tension of the piston return spring and moves the booster piston to the left. As a resuit, a hydraulic pressure is generated in the master cylinder. In this way, the braking performance ofthe vehicle is assured at all times.
VACUUM HOSE
The vacuum hose provided between the engine suction system and the brake booster incorporates a check
valve.
Constam pressure chamber
(Almosphere
Bossier piston Reaction disc
PiSt0F" md Variable bressure chamber
(Atmosphere)
The vacuum hose bears a letter “ENGINE The arrowheaded direction must face toward the engine side.
Check valve
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BRAKE
FRONT BRAKE
The front brake employs a disc brake. A ventilation disc is available as optional equipment. The ventilation
disc features stable braking force during the braking at high speed running. The disc brake caliper is also available both for the standard disc and for the ventilation disc
re~assembling.
Standard disc
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NOTE:
The disc at the right side is symmetrical with ihat at the left side.
The iliusiration typically shows 'the disc at the left side. =
Front brake specifications
T 1
ype Standard disc 1 Ventilation disc item
D' t Cylinder I lame er mm
Area
22
22.89
Brake effective radius
Outer diameter mm Rotor
277
277
Clearance bemween pads mm
12.5
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BRAKE
DISC BRAKE PADS
The disc brake pad comes in two kinds according to materials; AK S405 (asbestos) and AK NS101 (Asbestos-free). The disc brake pad is used selectively depending upon its destination. As regards the disc brake pads. both the standard disc and ventilated disc employ a brake pad having the
same shape.
Disc brake pad specifications
Lining area
Materials
BR-10
