SECTION 4A
HYDRAULIC BRAKES
Specifications . . . . . . . . . . . . . . . . . . . . . . . . 4A-1
General Specifications . . . . . . . . . . . . . . . . . . 4A-1
Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . 4A-2
Noise or Vehicle Vibration When Applied
Brake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4A-2
Pulls to One Side When Braking . . . . . . . . . . . 4A-2
Poor Braking . . . . . . . . . . . . . . . . . . . . . . . . . . 4A-2Increasing Pedal Stroke (Pedal Goes to
Floor) or Brake Dragging . . . . . . . . . . . . . . . 4A-3
Poor Braking of Parking Brake . . . . . . . . . . . . 4A-3 TABLE OF CONTENTS
Component Locator . . . . . . . . . . . . . . . . . . . 4A-4
ABS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4A-4
ABS / ABD . . . . . . . . . . . . . . . . . . . . . . . . . . . 4A-5
Non-ABS / ABD . . . . . . . . . . . . . . . . . . . . . . . . 4A-6
Maintenance and Repair . . . . . . . . . . . . . . . 4A-7
On-Vehicle Service . . . . . . . . . . . . . . . . . . . . . 4A-7
Bleeding the Brakes . . . . . . . . . . . . . . . . . . . . 4A-7
Brake Pedal . . . . . . . . . . . . . . . . . . . . . . . . . . 4A-9
LCRV (Load Conscious Reducing Valve) . . . 4A-12
Caution: Disconnect the negative battery cable before removing or installing any electrical unit or when a tool or equipment could easily come in contact with exposed electrical terminals. Disconnecting thiscable will help prevent personal injury and damage to the vehicle. The ignition must also be in LOCKunless otherwise noted.
Type
Pedal Ratio
Pedal Stroke
Pedal Freeplay Type
Inner Diameter Type
Ratio
Type
I.D. of Caliper Cylinder
Thickness of Brake Pad Thickness of Disc Plate Type
I.D. of Caliper Cylinder
Thickness of Brake Pad Thickness of Disc Plate
Type
Operation
Specification PBR Brake
4.3 : 1
132 mm
23.81 mm
5.0 : 1
60.4 mm
40.5 mm
9.5 mm
Suspended
1 - 4 mm
Tandem Type with Lever Sensor
Vacuum Booster Type
Ventilated Disc 10 mm 24 mm
Rear Wheel Internal Expansion Type Mechanical
SAE J1703, DOT3
SPECIFICATIONS
GENERAL SPECIFICATIONS
Brake Pedal
Master Cylinder Brake Booster Front Brake
Rear Brake
Parking Brake Brake Fluid MANDO Brake
4.3 : 1
138 mm
25.4 mm
5.6 : 1
60 mm
Solid Disc
38.2 mm
10.0 mm 10.4 mm
Application
4A-2 HYDRAULIC BRAKESCheck
Dirty or Lack of Fluid Air in Brake SystemFaulty Brake Booster Poor Contact of Pad or Lining Oil or Grease on PadFaulty Auto AdjusterOver Heated Rotor Due to Dragging Pad or LiningClogging Brake Line
Faulty Proportioning Valve Check
Incorrect Tire Pressure Between Left and Right Poor Contact of Pad or LiningOil or Grease is Applied to Pad or LiningBent or Uneven Wear of DrumIncorrectly Mounted Wheel Cylinder Faulty Auto Adjuster Action
Repair
Retighten Replace Replace
RepairRepair
Lubricate
Retighten
Check
Incorrectly Mounted Back Plate or CaliperLoosened Bolt of Back Plate or CaliperCrack or Uneven Wear of Brake Drum or DiscPad or Lining Sticking to Contact Surface Excessive Clearance Between Caliper and Pad Uneven Contact of PadLack of LubricationLoosened Suspension DIGNOSIS
NOISE OR VEHICLE VIBRATION WHEN APPLIED BRAKE
PULLS TO ONE SIDE WHEN BRAKING
Action Adjust
Repair
Replace Replace
Repair
Replace
Action
Replenish or Replace(Check eventual leakage) Bleeding
Replace
Repair
Replace Replace RepairRepair
Repair
POOR BRAKING
( If low cut-in : Adjust ) ( If Leakage : Replace )
HYDRAULIC BRAKES 4A-3
Check
Air in Brake system Fluid LeakingExcessive Clearance Between Push Rod and M/cylinder Parking Brake is not Fully Released Incorrect Adjustment of Parking BrakeWeak Return Spring of Brake PedalIncorrect Pedal FreeplayBroken Rear Drum Brake Shoe Return Spring Lack of Lubrication
Damaged Master Cylinder Check Valve or Piston Return Spring Action
Bleeding
RepairAdjust
Repair Adjust
Replace
Repair
Replace
lubricate Replace
INCREASING PEDAL STROKE (PEDAL GOES TO FLOOR)
OR BRAKE DRAGGING
Check
Insufficient Clearance Between Push Rod and Master Cylinder Worn Brake Lining Oil or Grease on Lining Binding Parking Brake CableFaulty Auto AdjusterExcessive Lever Stroke Action
Adjust
Replace Replace ReplaceReplace
Adjust or Check Cable
POOR BRAKING OF PARKING BRAKE
HYDRAULIC BRAKES 4A-7
MAINTENANCE AND REPAIRON-VEHICLE SERVICE
BLEEDING THE BRAKES For Master Cylinder Replacement
1. Add oil after master cylinder replacement.
2. Run the engine and depress the brake pedal several times to build pressure and then keep the pedal fully depressed.
3. Loosen the screws of primary and secondary pipe at the master cylinder outlets to bleed air.
4. Repeat above step No.3 several times until there are no more air bubbles.
5. Bleed air in the system at the hydraulic unit outlet pipe and wheel if pressure building is not enough by depressing the pedal only after above air bleeding.
For Caliper and Brake Hose Replacement
1. Check the oil level from the oil reservoir and refill if necessary.
2. Run the engine and depress the pedal several times to build pressure and then keep the pedal fully depressed.
3. Connect a vinyl tube to the caliper breather and prepare a container to coentain brake oil.
4. Loosen the breather screw until there are no more bubbles.
5. Bleed air in the system at four (4) wheels in order as shown in right figure if pressure building is not enough by depressing the pedal after above air bleeding.
Tightening Torque
9 - 14 NmItem
Front Bleeder Screw
Rear Bleeder Screw
Notice
Do not reuse the bled brake fluid.
Always bleed the air after replacing brake fluid or
master cylinder, caliper, brake hose and pipe.
Always operate in normal order.
HYDRAULIC BRAKES 4A-13
Construction LCRV consists of sensing part and hydraulic control part.
1. Sensing PartIt detects the changes of vehicle height caused by vehicle load. It consists of load sensing spring and control leverwhich change according to vehicle load.
2. Hydraulic Control Part It consists of valve stem devices which controls hydraulicpressure according to load detected by sensing part.
Trouble Shooting Poor Braking Possible Cause
Air in Brake System Poor Adjustment of Sensor SpringDamaged Sensor SpringFluid Leaking from LCRV Remedy
Bleeding Adjust
Replace Replace
Possible Cause
Poor Adjustment of Sensor Spring Internal Fluid Leaking of LCRV Remedy
Adjust
Replace
Abnormal Locking