YH4
GRAND
VITARA
[FOR VEHICLE WITHOUT ABS]
[FOR VEHICLE WITH ABS]
1. Master cylinder
2-1. 4-way joint
2-2. 2-way joint
3. LSPV (Load Sensing Proportioning Valve)
4. Rear axle housing
5. ABS actuator (H.U.)
F.R.:Front side
5-2 BRAKES
GENERAL DESCRIPTION
When the foot brake pedal is depressed, hydraulic pressure is developed in the master cylinder to actuate pistons
(two in front and four in rear).
The master cylinder is a tandem master cylinder. Brake pipes are connected to the master cylinder and they make
two independent circuits. One connects front brakes (right and left) and the other connects rear brakes (right and
left).
The load sensing proportioning valve (LSPV) is included in these circuits between the master cylinder and the rear
brake for the vehicle without ABS.
In this brake system, the disc brake type is used for the front wheel brake and a drum brake type (leading / trailing
shoes) for the rear brake.
The parking brake system is mechanical. It applies brake force to only rear wheels by means of the cable and me-
chanical linkage system. The same brake shoes are used for both parking and foot brakes.
YH4
GRAND
VITARA
BRAKES 5-3
SUBSTANDARD OR
CONTAMINATED BRAKE FLUID
Improper brake fluid, mineral oil or water in the fluid
may cause the brake fluid to boil or the rubber compo-
nents in the hydraulic system to deteriorate.
If primary piston cups are swollen, then rubber parts
have deteriorated. This deterioration may also be evi-
denced by swollen wheel cylinder piston cups on the
drum brake wheels.
If deterioration of rubber is evident, disassemble all
hydraulic parts and wash with alcohol. Dry these parts
with compressed air before assembly to keep alcohol
out of the system. Replace all rubber parts in the sys-
tem, including hoses. Also, when working on the
brake mechanisms, check for fluid on the linings. If ex-
cessive fluid is found, replace the linings.
If master cylinder piston seals are satisfactory, check
for leakage or excessive heat conditions. If condition
is not found, drain fluid, flush with brake fluid, refill and
bleed system.
The system must be flushed if there is any doubt as
to the grade of fluid in the system or if fluid has been
used which contained parts that have been subjected
to contaminated fluid.
DIAGNOSIS
ROAD TESTING BRAKES
Brakes should be tested on dry, clean, smooth and
reasonably level roadway which is not crowned. Road
test brakes by making brake applications with both
light and heavy pedal forces at various speeds to de-
termine if the vehicle stops evenly and effectively.
Also drive vehicle to see if it leads to one side or the
other without brake application. If it does, check the
tire pressure, front end alignment and front suspen-
sion attachments for looseness. See diagnosis chart
for other causes.
BRAKE FLUID LEAKS
Check the master cylinder fluid levels. While a slight
drop in reservoir level does result from normal lining
wear, an abnormally low level indicates a leak in the
system. In such a case, check the entire brake system
for leakage. If even a slight evidence of leakage is
noted, the cause should be corrected or defective
parts should be replaced.
If fluid level is lower than the minimum level of reser-
voir, refilling is necessary. Fill reservoir with specified
brake fluid.
Brake fluid: Refer to reservoir tank cap.
CAUTION:
Since brake system of this vehicle is factory-
filled with brake fluid indicated on reservoir
tank cap, do not use or mix different type of
fluid when refilling; otherwise serious damage
will occur.
Do not use old or used brake fluid, or any fluid
from a unsealed container.
YH4
GRAND
VITARA
5-4 BRAKES
DIAGNOSIS TABLE
ConditionPossible CauseCorrection
Not enough brak-
ing forceBrake oil leakage from brake lines.
Brake disc or pads stained with oil.
Overheated brakes.
Poor contact of shoes on brake drum.
Brake shoes linings stained with oil or wet
with water.
Badly worn brake shoe linings.
Defective wheel cylinders.
Malfunctioning caliper assembly.
Air in system.
Maladjusted sensor spring length of LSPV.
Broken sensor spring of LSPV.
Defective collar of LSPV.
Malfunctioning ABS (Antilock brake system),
if equipped.Locate leaking point and repair.
Clean or replace.
Determine cause and repair.
Repair for proper contact.
Replace.
Replace.
Repair or replace.
Repair or replace.
Bleed system.
Check or adjust.
Replace.
Replace.
Check system and replace as
necessary.
Brake pull
(Brakes not work-
ing in unison)Pad or shoe linings are wet with water or
stained with oil in some brakes.
Drum-to-shoe clearance out of adjustment in
some brakes.
(Malfunctioning auto adjusting mechanism)
Drum is out of round in some brakes.
Wheel tires are inflated unequally.
Malfunctioning wheel cylinders.
Disturbed front end alignment.
Unmatched tires on same axle.
Restricted brake pipes or hoses.
Malfunctioning caliper assembly.
Loose suspension parts.
Loose calipers.Replace.
Check for inoperative auto adjusting
mechanism.
Replace.
Inflate equally.
Repair or replace.
Adjust as prescribed.
Tires with approximately the same
amount of tread should be used on the
same axle.
Check for soft hoses and damaged
lines.
Replace with new hoses and new
brake pipes.
Check for stuck or sluggish pistons
and proper lubrication of caliper slide
bush.
Caliper should slide.
Check all suspension mountings.
Check and torque bolts to specifica-
tions.
Noise (High pitched
squeak without
brake applied)Front lining worn out.Replace linings.
Rear brake locked
prematurelyMaladjusted sensor spring length of LSPV.
Malfunction LSPV assembly.Check or adjust.
Replace assembly.
Brake locked
(For vehicles
equipped with
ABS)Malfunctioning ABS, if equipped.Check system and replace as
necessary.
YH4
GRAND
VITARA
BRAKES 5-5
ConditionPossible CauseCorrection
Excessive pedal
travel (Pedal
stroke too large)Partial brake system failure.
Insufficient fluid in master cylinder
reservoirs.
Air in system. (pedal soft / spongy)
Rear brake system not adjusted.
(malfunctioning auto adjusting mechanism)
Bent brake shoes.
Worn rear brake shoes.Check brake systems and repair as
necessary.
Fill reservoirs with approved brake
fluid.
Check for leaks and air in brake
systems.
Check warning light. Bleed system if
required.
Bleed system.
Repair auto adjusting mechanism.
Adjust rear brakes.
Replace brake shoes.
Replace brake shoes.
Dragging brakes
(A very light drag
is present in all
disc brakes
immediately
after pedal is
released)Master cylinder pistons not returning
correctly.
Restricted brake pipes or hoses.
Incorrect parking brake adjustment on rear
brakes.
Weakened or broken return springs in the
brake.
Sluggish parking-brake cables or linkage.
Wheel cylinder or caliper piston sticking.
Malfunctioning ABS, if equipped with ABS.Replace master cylinder.
Check for soft hoses or damaged
pipes and replace with new hoses
and / or new brake pipes.
Check and adjust to correct specifi-
cations.
Replace.
Repair or replace.
Repair as necessary.
Check system and replace as
necessary.
Pedal pulsation
(Pedal pulsates
when depressed
for braking)Damaged or loose wheel bearings.
Distorted steering knuckle or rear axle
shafts.
Excessive disc lateral runout.
Parallelism not within specifications.
Rear drums out of round.Replace wheel hub component.
Replace knuckle or rear axle shaft.
Check per instructions. If not within
specifications, replace or machine
the disc.
Check per instructions. If not within
specifications, replace or machine
the disc.
Check runout.
Repair or replace drum as
necessary.
Braking noiseGlazed shoe linings, or foreign matters
stuck to linings.
Worn or distorted shoe linings.
Loose front wheel bearings.
Distorted backing plates or loose mounting
bolts.Repair or replace shoe lining.
Replace shoe lining (or pad).
Replace wheel hub component.
Replace or retighten securing bolts.
YH4
GRAND
VITARA
5-6 BRAKES
ConditionPossible CauseCorrection
Brake warning light
turns on after
engine startParking brake applied.
Insufficient amount of brake fluid.
Brake fluid leaking from brake line.
Brake warning light circuit faulty.
Malfunctioning EBD system, if equipped
with ABS.Release parking brake and check
that brake warning light turns off.
Add brake fluid.
Investigate leaky point, correct it and
add brake fluid.
Repair circuit.
Check system referring to
ªDIAGNOSISº of ABS section.
Brake warning light
turns on when
brake is appliedBrake fluid leaking from brake line.
Insufficient amount of brake fluid.Investigate leaky point, correct it and
add brake fluid.
Add brake fluid.
Brake warning light
fails to turn on
even when parking
brake is appliedBulb burnt out.
Brake warning light circuit open.Replace bulb.
Repair circuit.
ABS warning light
does not turn on
for 2 sec. after
ignition switch has
turned ONBulb burnt out.
ABS warning light circuit open, if equipped
with ABS. (including check relay)Replace bulb.
Check system referring to
ªDIAGNOSISº of ABS section.
ABS warning light
remains on after
ignition switch has
turned on for 2 sec.Malfunctioning ABS, if equipped with ABS.Check system referring to
ªDIAGNOSISº of ABS section.
YH4
GRAND
VITARA
1. 4-way joint / 2-way joint
2. Master cylinder
3. LSPV
4. Right brake caliper
5. Left brake caliper
6. Right wheel cylinder
7. Left wheel cylinder
8. ABS actuator
: Air bleeding point [A]: Without ABS
[B]: With ABS
1. Plug cap2. Vinyl tube (See-through tube)
3. Container
[A]
[B]
BRAKES 5-7
CHECK AND ADJUSTMENT
BLEEDING BRAKES
CAUTION:
Brake fluid is extremely damaging to paint. If fluid should
accidentally touch painted surface, immediately wipe
fluid from paint and clean painted surface.
NOTE:
For vehicle equipped with ABS, make sure that ignition switch
turns off.
Be sure to bleed air of brake system according to following proce-
dure when its oil hydraulic circuit has been disconnected.
Hydraulic lines of brake system consists of two separate lines, one
for front wheel brakes and the other for rear wheel brakes.
Air bleeding is necessary at right and left front wheel brakes, left
rear wheel brake and LSPV (if equipped without ABS), i.e. 4 places
(3 places for vehicle with ABS) in all.
1) Fill master cylinder reservoir with brake fluid and keep at least
one-half full of fluid during bleeding operation.
2) Remove bleeder plug cap.
Attach a vinyl tube to bleeder plug of wheel cylinder, and insert
the other end into container.
3) Depress brake pedal several times, and then while holding it de-
pressed, loosen bleeder plug about one-third to one half turn.
YH4
GRAND
VITARA
5-8 BRAKES
4) When fluid pressure in the cylinder is almost depleted, retigh-
ten bleeder plug.
5) Repeat this operation until there are no more air bubbles in hy-
draulic line.
6) When bubbles stop, depress and hold brake pedal and tighten
bleeder plug.
For tightening torque specification of air bleeder plug, re-
fer to ªTIGHTENING TORQUE SPECIFICATIONº in this
section.
7) Then attach bleeder plug cap.
8) After completing bleeding operation, apply fluid pressure to
pipe line and check for leakage.
9) Replenish fluid into reservoir up to specified level.
10) Check brake pedal for ªsponginessº. If found spongy, repeat
entire procedure of bleeding.
YH4
GRAND
VITARA
1. Stop light switch
BRAKES 5-9
BRAKE PEDAL FREE HEIGHT CHECK
Remove foot rest and displace carpet and dash silencer(s) so as to
measure brake pedal free height between pedal face and asphalt
sheet installed on dash panel.
Brake pedal free height ªaº from asphalt sheet:
208 ± 218 mm (8.19 ± 8.58 in.)
If the measurement is not within the specification, check the posi-
tion of booster push rod clevis and / or stop light switch according
to the instruction shown in this section.
The free height varies depending on installation position of booster
push rod clevis and stop light switch.
BRAKE LIGHT SWITCH ADJUSTMENT
Adjustment should be made as follows when installing switch. Pull
up brake pedal toward you and while holding it there, adjust switch
position so that clearance between end of thread and brake pedal
return cushion (shown as ªbº in figure).
Then tighten lock nut to specified torque.
Clearance ªbº: 1.5 ± 2.0 mm (0.06 ± 0.08 in.)
Tightening Torque
(b): 7.5 N
.m (0.75 kg-m, 5.5 lb-ft)
EXCESSIVE PEDAL TRAVEL CHECK
1) Remove foot rest and displace carpet and dash silencer(s).
2) Start engine.
3) Depress brake pedal a few times.
4) With brake pedal depressed with approximately 30 kg (66 lbs)
load, measure pedal to asphalt sheet clearance ªcº.
Clearance ªcº: over 115 mm (4.53 in.)
5) If clearance ªcº is less than specification, the most possible
cause is either rear brake shoes are worn out beyond limit or air
is in lines.
Should clearance ªcº remain less than specification even after
replacement of brake shoes and bleeding of system, other pos-
sible but infrequent cause is malfunction of rear brake shoe ad-
justers or booster push rod length out of adjustment.