1987 SUZUKI GRAND VITARA Service Repair Manual

18-10. RECOMMENDED TORQUE SPECIFICATIONS
Fastening partsN-m
Tightening torque
kg-mlb-ft
Steering shaft nut25 - 402.5 - 4.018.5 - 28.5
ISteering shaft rubber joint boltI15-25I1.5- 2.5Ill.O- 18.0IL,
Steering shaft joint flangebolt20 - 302.0-3.014.5-21.5
Steering gear box nut70-907.0-9.051 .O-65.0
Drag rod castle nut30 - 703.0-7.022.0-50.5III
Tierodendcastlenut30-553.0-5.522.0-39.5
Tie rod end locknut70 - 1007.0- 10.051 .O-72.0
Steering damperstaynut18-281.8-2.813.5-20.0
Steeringdampernut35-553.5-5.525.5-39.5
Steeringdamperpin nut22-352.2-3.516.0-25.0
Steeringcolumnbolt & nut11-171.1-1.78.0-12.0
18-22

SECTION 19
BRAKES
CONTENTS
19-1. GENERAL DESCRIPTION................................. 19-2
19-2. FRONT DISC BRAKE..................................... 19-14
19-3. REAR DRUM BRAKE..................................... 19-20
19-4. MASTER CYLINDER..................................... 19-27
19-5. BRAKE BOOSTER....................................... 19-30
19-6. PARKING BRAKE........................................ 19-38
19-7. BRAKE PIPES AND HOSES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-39
19-8. MAINTENANCE SERVICE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-42
19-9. TORQUE SPECIFICATION.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-49
NOTE:
All brake fasteners are important attaching parts in that they could affect the performance
of vital parts and systems, and/or could result in major repair expense. They must be
replaced with one of same part number or with an equivalent part if replacement becomes
necessary. Do not use a replacement part of lesser quality or substitute design. Torque
values must be used as specified during reassembly to assure proper retention of all parts.
There is to be no welding as it may result in extensive damage and weakening of the
metal.
WARNING:
When servicing wheel brake parts, do not create dust by grinding, sanding brake linings,
or by cleaning wheel brake parts with a dry brush or with compressed air. Many wheel
brake parts contain asbestos fibers which can become airborned if dust is created dur-
ing servicing. Breathing dust containing asbestos fibers may cause serious bodily harm.
A water dampened cloth or water based solution should be used to remove any dust
on brake parts. Equipment is commercially available to perform this washing function.
These wet methods will prevent asbestos fibers from becoming airborne.
19-1

19-1. 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. Two brake pipes are connected to the master cylinder
and they make two independent circuits. One connects the front brakes (right & left) and the other
connects the rear brakes (right & left).
The proportioning and bypass valve (P& B valve) is included within the brake circuit which connects the
master cylinder and the rear wheel brake.
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 wheel brake.
The parking brake system is mechanical. It applies brake force to only rear wheels by means of the cable
and mechanical linkage system. The same brake shoes are used for both parking and foot brakes.
\Right side
Left side
1. Brake booster2.Master cylinder
3.Secondary side
4.Primary side
5.6 jointway
6. P & B (Proportioning and bypass) valve
7.Parking brake lever
8.Differential
9.Rear axle housing
Fig. 19-1
19-2

MASTER CYLINDER
16
1
I
/
//5//
4 ----A /’/
1. Brake master cylinder assembly
2. Brake master cylinder piston set
3. Piston stopper circlip
4. Secondary piston stopper bolt
5. Seal ring
6. Piston stopper seal ring
7. Cylinder cup8. Master cylinder seal ring9. Connector screw
10. Reservoir connector grommet
11. Master cylinder reservoir
12. Cylinder reservoir strainer13. Cylinder reservoir cap
14. Breather cap15. Master cylinder gasket
16. Brake booster assembly
Fig. 19-2
19-3

MASTER CYLINDER ASSEMBLY
[GENERAL DESCRIPTION]
The master cylinder has two pistons and three piston cups. Its hydraulic pressure is produced in the
primary (“a” in the below figure) and secondary (“b”) chambers. The hydraulic pressure produced in the
primary chamber (“a”) acts on the front wheel brakes (right & left).
Also, the hydraulic pressure produced in the secondary chamber (“b”) acts on the rear wheel brakes
(right & left).
NOTE:
Replace all components included in repair kits to service this master cylinder. Lubricate rubber parts with
clean, fresh brake fluid to ease assembly. Do not use lubricated shop air on brake parts as damage to rubber
components may result. If any hydraulic component is removed or brake line disconnected, bleed the
brake system. The torque values specified are for dry, unlubricated fasteners.
1.Piston stopper circllp
2.Piston stopper
3.Piston stopper sealing
4.Primary piston
5.Piston cup
6.Secondary piston pressure cup
7.Piston cup
8Secondary piston
9.Return spring secondary seat
10.Secondary piston return spring
11.Secondary piston stopper bolt
12.Master cylinder body
A :Primary piston
BSecondary piston
Fig. 19-3
[Master cylinder OPERATION]
Normal operation
Depressing the brake pedal forces the primary piston“A” to move to the left in the below figure and
consequently the hydraulic pressure is produced in the chamber “a”.
By means of this pressure and the return spring force, the secondary piston “B” is also pushed to the left
and thus the hydraulic pressure is produced in the chamber “b”.
Fig. 19-3-1
19-4

One-circuit operation (Primary chamber “a” circuit failure)
Depressing the brake pedal forces the primary piston “A” to move as described previously, but since the
brake circuit connected to the chamber “a” cannot hold the pressure, no pressure is produced in the fluid
immediately ahead of the piston“A”. The piston “A” keeps moving while compressing the spring and
when it reaches the retainer, the piston “B” is pushed and begins to move. This causes the pressure to rise
in the chamber “b” and the pressure acts on rear wheel brakes (right & left).
One-circuit operation (Secondary chamber “b” circuit failure)
In this case, the leftward movement of the piston “A” has but little effect in causing the fluid pressure to
rise in the chamber “a” in the beginning, because the initial rise of the fluid pressure causes the piston “B”
to promptly yield and move to the left. However, when the forward end of the piston “B” comes to the
head of the cylinder and stops there, the Ieftward movement of the piston “A” becomes effective. Thus
the’fluid pressure is produced in the chamber “a” and it acts on front wheel brakes (right & left).
The below figure shows secondary piston “B” at halt.
19-5
Fig. 19-4
Fig. 19-4

DISC BRAKE CALIPER ASSEMBLY
[GENERAL DESCRIPTION]
This caliper has a single 51.1 mm (2.012 in.) bore and is mounted to the brake caliper holder with two
mounting bolts. Hydraulic force, created by applying force to the brake pedal, is converted by the caliper
to friction. The hydraulic force acts equally against the piston and the bottom of the caliper bore to move
the piston outward and to move (slide) the caliper inward, resulting in a clamping action on the disc. This
clamping action forces the pads (linings) against the disc, creating friction to stop the car.
For details, refer to OPERATION in the next page.
NOTE:
Lubricate parts as specified. Do not use lubricated shop air on brake parts as damage to rubber compo-
nents may result If any component is removed or line disconnected, bleed the brake system. Replace
pads in axle sets only. The torque values specified are for dry, unlubricated fasteners.
1. Caliper guide pin
2. Caliper guide pin sleeve
3. Guide pin boot
4. Guide pin cap
5. Bleeder plug cap
6.Bleeder plug
7. Disc brake caliper(Disc brake cylinder)
8.Piston seal9. Disc brake piston
10.Cylinder boot
11. Disc brake pad12. Disc brake carrier
13. Caliper antirattle clip14.Caliper holder
15.Dust cover16.Brake disc
Fig. 19-5
19-6

[Caliper OPERATION]
Single piston floating caliper type
The single piston floating caliper type brake is
employed in this model. One cylinder and one
piston are used for this type. (The cylinder is
constructed as a monoblock with the caliper.)
Fluid pressure generated in the cylinder causes
the pad (1) on the piston side to press against
the disc. At the same time, the floating type
caliper body is moved to the right by the cylin-
der pressure, as shown in below figure, which
pulls pad (2) against the disc and so brakes the
wheel.
Caliper body
\Brake disc (rotor)
Fig. 19-6 - ’
The disc brake has no servo assistance as in drum
braking, and it is necessary to increase the work-
ing pressure of the piston and pad. For this pur-
pose, the wheel cylinder has a large bore. Even
only a little change in clearance between the disc
and pad has therefore a large influence on the
brake pedal stroke. It is necessary to have the
clearance adjusted to the minimum at all times,
by means of the piston (rubber) seal.
Piston seal (Rubber seal)Piston sealWinder (Rubber seal)
II
IPiston
Hydraulic pressure
“OFF“
Fig. 19-7
Clearance correction
Piston
Hydraulic pressure
“ON”
When oil pressure is applied to the piston, the
piston moves forward. The rubber seal, which
exerts considerable pressure against the piston,
moves with the cylinder. However, as a part of
the rubber seal has been fixed into a groove in
the cylinder, the shape of the rubber seal is dis-
torted toward internal end of the cylinder, as
shown in above figure. When pressure is taken
off from the foot brake pedal and fluid pressure
is released from the piston, a restoring force is
generated at the seal and pushes the piston back.
As the pads wear away and the clearance be-
tween the disc and pads becomes larger, the
piston moves a larger distance. The seal then
could change in shape further but, since the end
of the seal is fixed into the groove in the cylin-
der, the distortion is limited to the same amount
as previously described. The piston moves
further to cover the distance of clearance. The
piston returns by the same distance and the
rubber seal recovers its shape as described
above and thus the clearance between the disc
and pads are maintained in adjustment.
19-7
Cylinder