Suzuki Grand Vitara JB627. Manual - part 171

4A-3 Brake Control System and Diagnosis: 

Rear Brake Hose / Pipe Construction

S6JB0B4101003

5. ABS (ESP

®) hydraulic unit / control module assembly

: 11 N

⋅m (1.1 kgf-m, 8.0 lb-ft)

6. Master cylinder

I5JB0A410003-02

1. To left rear brake hose

3. Left rear brake hose

2. To right rear brake hose

4. Right rear brake hose

Brake Control System and Diagnosis:  4A-4

Master Cylinder Assembly Construction

S6JB0B4101004

The master cylinder has two pistons, two pressure seal (3) and two separating seal (4). Its hydraulic pressure is 
produced in the primary (A in the figure) and secondary (B) chambers. The hydraulic pressure produced in the primary 
chamber (A) acts on the front right and rear left brakes.
Also, the hydraulic pressure produced in the secondary chamber (B) acts on the front left and rear right brakes.

WARNING

!

 

Brake master cylinder cannot be disassembled. When anything faulty is found in it, it must be replaced 
as an assembly.

 

CAUTION

!

 

Brake master cylinder cannot be disassembled in principle. Should primary piston (1) have come off 
from cylinder while dismounting or handling it, wash it in the same specified fluid as that in reservoir 
and place it back in cylinder.

 

Booster Assembly Construction

S6JB0B4101005

The booster is located between the master cylinder and the brake pedal. It is so designed that the force created when 
the brake pedal is depressed is mechanically increased combined with the engine vacuum.

CAUTION

!

 

• Never disassemble brake booster assembly. If it is found faulty, replace it with new assembly.
• The torque values specified are for dry, unlubricated fasteners. If any hydraulic component is 

removed or brake line disconnected, bleed the brake system.

 

I5JB0A410004-01

2. Secondary piston

6. Secondary piston return spring

8. O-ring

5. Primary piston return spring

7. Grommet

9. Master cylinder body

4A-5 Brake Control System and Diagnosis: 

Diagnostic Information and Procedures

Brake Diagnosis Note

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Road Test for 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 
determine 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 suspension 
attachments for looseness. 
See diagnosis flow table for other causes.

Brake Fluid Inspection
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 reservoir, 
refilling is necessary. 
Fill reservoir with specified brake fluid.

Brake fluid
: Refer to reservoir cap.

CAUTION

!

 

Since brake system of this vehicle is factory 
filled with brake fluid indicated on reservoir 
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.

 

Brakes Symptom Diagnosis

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Condition

Possible cause

Correction / Reference Item

Not enough braking force Brake fluid leakage

Locate leaking point and repair.

Brake disc or pad stained with fluid

Clean or replace.

Overheated brakes

Determine cause and repair.

Poor contact of brake shoe on brake 
drum

Repair for proper contact.

Brake shoe stained with fluid or wet with 
water

Clean or replace.

Badly worn brake pad and brake shoe

Replace.

Defective wheel cylinders

Repair or replace.

Malfunctioning caliper assembly

Repair or replace.

Air in system

Bleed system.

Malfunctioning ABS (ESP

®), if equipped Check system and replace as necessary.

Brake Control System and Diagnosis:  4A-6

Brake pull 
(Brakes not working in 
unison)

Pad, disc, shoe and/or drum are wet 
with water or stained with fluid in some 
brakes

Clean or replace.

Drum-to-shoe clearance out of 
adjustment in some brakes. 
(malfunctioning auto adjusting 
mechanism)

Check for inoperative auto adjusting 
mechanism.

Drum is out of round in some brakes

Replace.

Wheel tires are inflated unequally

Inflate equally.

Malfunctioning wheel cylinders

Repair or replace.

Disturbed front end alignment

Adjust as prescribed.

Unmatched tires on same axle

Tires with approximately the same amount of 
tread should be used on the same axle.

Restricted brake pipes or hoses

Check for soft hoses and damaged lines. 
Replace with new hoses and new brake piping.

Malfunctioning caliper assembly

Check for stuck or sluggish pistons and proper 
lubrication of caliper slide bush.

Loose suspension parts

Caliper should slide. Check all suspension 
mountings.

Loose calipers

Check and torque bolts to specifications.

Brake locked

Malfunctioning ABS (ESP

®)

Check system and replace as necessary.

Excessive pedal travel
(Pedal stroke too large)

Partial brake system failure

Check brake systems and repair as necessary.

Brake fluid leaking

Locate leaking point and repair. Then air bleed.

Air in system (pedal soft / spongy)

Bleed system.

Rear brake system not adjusted 
(malfunctioning auto adjusting 
mechanism)

Repair auto adjusting mechanism. Adjust rear 
brakes.

Bent brake shoes

Replace brake shoes.

Dragging brakes
(Without a very light drag 
is present in all disc 
brakes immediately after 
pedal is released)

Master cylinder pistons not returning 
correctly

Replace master cylinder.

Restricted brake pipes or hoses

Check for soft hoses or damaged pipes and 
replace with new hoes and/or new brake pipes.

Incorrect parking brake adjustment on 
rear brake

Check and adjust to correct specifications.

Weakened or broken return springs in 
the rear brake

Replace.

Sluggish parking-brake cables or 
linkage

Repair or replace.

Wheel cylinder or brake caliper piston 
sticking

Repair as necessary.

Malfunctioning ABS (ESP

®)

Check system and replace as necessary.

Pedal pulsation
(Pedal pulsates when 
depressed for braking)

Damaged wheel bearings

Replace wheel hub.

Distorted steering knuckle or rear 
suspension knuckle

Replace knuckle.

Excessive disc lateral runout

Check per instructions. If not within 
specifications, replace or machine the disc.

Rear brake drum out of round

Check runout. Repair or replace drum as 
necessary.

Brake caliper stick

Check slide pin of brake caliper.

Braking noise

Glazed brake pad and/or brake shoe

Repair or replace brake pad and/or brake 
shoe.

Worn or distorted brake pad and/or 
brake shoe

Replace brake pad and/or brake shoe.

Worn wheel bearings

Replace wheel hub.

Distorted backing plates

Replace.

Condition

Possible cause

Correction / Reference Item