JAC S2 (Chassis). Instruction — part 8

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3) Load the vehicle tool box.
4) Close the spare tire cover.

5) Close the trunk lid.

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Brake system

I. Overview

(I) Structure Summary

Brake system diagram (front & rear plate models)

1. Left front brake caliper assembly
2. Right front brake caliper assembly
3. Front brake discs
4. Rear brake disc
5. Left rear brake caliper assembly
6. Right rear brake caliper assembly
7. Master cylinder flow lines assembly
8. Front brake exhaust pipe assembly
9. Right front brake pipe assembly
10. Rear brake exhaust pipe assembly
11. Left front brake hose assembly
12. Right front brake hose assembly
13. Left rear brake hose assembly Ⅱ
14. Right rear brake hose assembly Ⅱ
15. Vacuum booster with brake master pump assembly
16. Brake pedal assembly

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Rear disc brake caliper structure (Front & Rear plate models)

1. The guide seat
2. Strut nut
3. The torsion spring
4. Strut
5. Guide seat bolt
6. Plug
7. Hex head bolt
8. Cylinder
9. The Under-pin
10. The bushing
11. Piston composition
12. Dust cover
13. The yoke spring
14. The inner brake assembly
15. Bracket
16. Bleeder screw and nut

17. The outer brake assemblyVacuum booster assembly diagram

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1. The vacuum booster
2. The master cylinder
3. Brake fluid reservoir

Hydraulic line chart

1. Brake master cylinder 2. ABS / ESP module assembly

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(II) Maintenance data and Specifications

Item

Specifications

master cylinder

type

Cascade

cylinder bore

22.22mm

brake booster

type

vacuum

Size (size)

10 inches

assist ratio

7.3:1

Front brake (front
disc rear drum
type)

type

Floating type/ventilated disc

Brake disc diameter

256mm

Brake disc thickness

22mm

Friction block thickness 10.8mm

cylinder bore

54mm

Rear brake (front
disc rear drum type)

type

Drum brake

Sub brake disc diameter

17.46mm

Brake disc thickness

204mm

Friction block thickness 4mm

Front brake (front
disc rear disc type)

type

Floating type/ventilated disc

Brake disc diameter

294mm

Brake disc thickness

25mm

Friction block thickness 9.5mm

cylinder bore

54mm

Rear brake (front
disc rear disc type)

type

Floating type/ventilated disc

Brake disc diameter

275mm

Brake disc thickness

9mm

Friction block thickness 8mm

cylinder bore

34mm

(III) Torque parameters

No. Item

Torque (N • m)

Remarks

1 front brake caliper and knuckle connecting bolt

75~85

2 rear brake caliper and torsion beam bolt

65~75

3 rear brake and rear hub connecting bolt

65~85

4 front and rear brake caliper bleeder screw

7~13

5 brake pedal upper bracket bolt

20~25

6 brake pedal fixing nut

20~25

7 brake hose and brake caliper bolt

25~30

8 brake hardware fittings

16~18

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(IV) Maintenance Precautions

1. All brake lines should not be excessive bending, twisting and stretching.
2. Verify that all vehicle brake lines do not interfere with other parts at ease or during steering.
3. The brake lines is an important safety part, always tighten its fixture. If found damaged parts, replace
the applicable component.
4. When disconnecting the brake pipe, please seal the connector end to avoid dust entering.
5. "DOT 4" brake fluid is recommended.
6. Do not reuse drained brake fluid.
7. Be careful not to splash brake fluid on painting, to avoid damaging the paint. If splashed on painted
areas, wash clean immediately with water.
8. Please wash with clean brake fluid all parts in the brake cylinder.
9. Do not use gasoline or kerosene and other mineral oil, to avoid damaging the rubber parts of the
hydraulic system.
10. Please use a dedicated pipe wrench when removing and installing tube, during brake tube
installation, be sure to check tightening torque.
11. After repairing or replacing brake discs, brake shoes, or appear lack of brake with a very short
distance, be sure to run-brake joint surface.
12. Make sure there is no brake fluid on the brake disc, do not spill brake fluid on the brake disc,
otherwise it will lead to brake failure.

II. Fault diagnosis

(I) Fault diagnosis table

Common braking system fault finding chart

No. Failure Cause Failure Analysis

Solution

Remark

1

when braking
the vehicle
deviate to one
side

insufficient left & right tire pressure adjust

Front wheel adjusted incorrectly

adjust

Brake shoe has poor contact

adjust

Brake shoe surface has grease or oil replace

brake drum eccentric or unevenly
worn

replace

Brake cylinder assembly adjusted
incorrectly

adjust

Self-adjusting mechanism is faulty

adjust

2 insufficient

braking force

lack of brake fluid or contaminated Refill to replace

Brake system has air

Drain the system

The brake booster is faulty

Adjust

Brake shoe has poor contact

Adjust

Brake shoe surface has grease or oil Replace

Self-adjusting mechanism is faulty

Adjust

Dragging brake shoe and brake
rotating parts cause overheating

Adjust

brake lines limits

Adjust

3

Increase the
pedal stroke

Brake system has air

Drain the system

Brake fluid leak

Adjust

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(pedal to the
floor to reduce
the distance)

Self-adjusting mechanism is faulty

Adjust

Pushrod to the brake master cylinder
gap is too big

Adjust

No. Failure

Cause

Failure Analysis

Solution

Remark

4

Brake
hysteresis

parking brake is not fully liberalized

liberalize

parking brake improperly adjusted

adjust

Brake pedal return spring worn

replace

Brake master cylinder reservoir port
restrictions

adjust

Rear drum brake return spring damaged

replace

lading parts insufficient lubrication

lubricate

One-way valve or the master cylinder
piston return spring defective

replace

master cylinder pushrod and gap is too
small

lubricate

5

parking
brake
function is
insufficient

rear brake shoe damage

adjust

The surface of rear brake shoe has grease
or oil

replace

Parking brake fastener jammed

adjust

Self-adjusting mechanism is faulty

adjust

The parking brake lever stroke is too big adjust

6 Braking

force is
insufficient

pipe joints or brake cylinder cups leak

wipe clean and tighten or
replace

Pipeline residual exhaust air is not
drained

drain

Shoe drum gap is too large

retune

Hoof surface sticky oil or hardened

friction or replace

The drum overheating, pipe vapor
resistance

Replace, cooling, drain

7 brake is

hard to
release

brake cylinder cups back to the hole
blocked or remove

expansion or replace

drum shoe gap is too small

retune

Shoe return spring elastic weakened or
broken

replace

Hoof or floor deformation, return
blocked

Adjust or replace

8 noise

rear brake shoe severely worn

replace

Brake drum out of round

Cut and need balance
performance verification

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Rear brake shoe surface is too smooth,
when friction coefficient is small and the
brake pressure is high, the noise will be
generated when friction and slipping the
smooth surface or when there is foreign
object between the extrusion friction
surface

After clearing the foreign
object, use sandpaper to polish
brake shoe

9 Brake

dragging
caused
brake drum
heating

brake gap and pedal free travel is too
small, when release the brake pedal, the
braking force is not fully liberated, so
that the friction lasts a long time; cause
start difficulties, driving weakness, when
touches the surface of the drum, it is hot

遇此情况 readjust the brake timing and

gap according to the request

brake handle is not fully liberalized,
caused by negligent operation or
improper adjustment, resulting in a long
time friction and heat

If necessary adjustments
according to specifications

The heat generated by braking causes
return spring thermal deformation, the
elastic force decline or disappear, which
makes that it after braking it cannot
guarantee that brake shoe assembly
return in time, the heat of the brake and
brake drum cannot be completely
removed

应检修或更 repair or replace the return

spring to eliminate failure

10 Parking

failure

Common brush or jacket rust, traction
spring break, fall off or elasticity
disappear, causing parking brake control
drawing or brake drawing is not flexible
in its coat, which makes the parking
brake does not release and cause failure.

Check whether there is injury
of the brake systems and brake
parts drawing surface, handle
maneuvers whether flexible
and without jam, the
connection of drawing is loose
and the fixed portion is
damaged, repair or replace
parts if necessary.

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III. Front brake pad friction plate

(I) Remove

△ Note To maintain wheel balance, before removing the

tire, mark the relative positions of the wheel.

1. Remove wheels refers to the wheels
2. Remove the front brake caliper friction plate group

1). Remove mounting bolts of the brake caliper assembly
positioning pin.

2). Flip caliper clamp body assembly.

△ Note avoid pulling the brake hose

S2-w3085b

3). Remove the inner and outer brake pads.

(II) Check

1. Check the thickness of brake shoe (disc brakes)

1). Check brake shoe thickness with the scale.

Front brake caliper Standard lining thickness (front disc rear drum models): 11mm

Front brake caliper pad wear limit thickness (front disc rear drum models): 2mm

Front brake caliper standard lining thickness (front disc rear disc models): 9.5mm

Front brake caliper pad wear limit thickness (front disc rear disc models): 2mm

Rear caliper standard lining thickness (front disc rear disc models): 8mm

Front brake caliper pad wear limit thickness (front disc rear disc models): 2mm

△ Note that if the brake shoe thickness less than the

thickness of the wear limit, replace the brake shoe

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S2-w3087b

(III) Installation

1. Install the caliper lining

1). Mount the caliper brake friction plate on the caliper
bracket.

2) Install front brake caliper assembly positioning pin
fixing bolts and tighten.
Tightening torque 35 ~ 45N • m

3). Fix brake disc, tread the brake pedal until the brake
respond.

4) Check the rotation resistance of brake caliper.

5) Install the wheel

IV. Front brake caliper assembly

(I) Remove

1. Remove the wheels refers to the wheels
2. Discharge brake fluid refers to brake fluid
3. Remove the front brake caliper assembly

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1). Remove the brake hose bolts and copper washer
connecting brake hose and front brake caliper.

△ Note attention not to drop copper washer on both ends

of the bolt

2). Remove the two mounting bolts connecting the front
brake caliper assembly and steering knuckle.

3) Remove the front brake caliper assembly.

(II) Installation

1. Install the front brake caliper assembly

1). Place the caliper assembly to the mounting position,
pre-tightening two mounting bolts connecting clamp
caliper assembly and steering knuckle.

2) Tighten two mounting bolts connecting clamp caliper
assembly and steering knuckle.
Tightening torque 75 ~ 85N • m

3) Install the caliper bolts and copper washers connecting
the front brake hose and front brake hose.

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Tightening torque 25 ~ 30N • m

2. Fill brake fluid refers to brake fluid
3. Drain brake system exhaust refers to the brake system exhaust
4. Install the wheel

V. Front brake discs

(I) Remove

1. Remove the wheels refers to the wheels.
2. Remove the front brake caliper assembly refers to front brake caliper assembly.
3. Remove the front brake disc.

1). Remove the brake discs on the front cross screws.

2) Remove the front brake discs.

(II) Check

1. Visually check

Check whether there is front brake disc surface uneven
wear, cracks and badly damaged. If yes, please replace it.

2. Check run out

1) Fix front brake disc to the hub.

△ Note before measurement, make sure the wheel bearing

axial clearance should not be too large.

2) Use a dial indicator to check run out. It can be
measured at 10mm inside edge of the brake disc

Run out limit: 0.05mm

3) If the run out exceeds the limit, replace the brake disc
or make the necessary processing.

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3. Check the thickness

1) Use a micrometer to check the brake disc thickness. If
the thickness is less than wear limit, replace the brake disc.

Standard thickness (front disc rear drum models): 22mm wear limit (front disc rear drum models):
20.4mm standard thickness (front disc rear disc models): 25mm wear limit (front disc rear disc models):
23mm

(III) Installation

1. Install the front brake discs

1) Install the front brake discs.

2) Tighten the cross-shaped screws.
Tightening torque 10 ~ 15N • m

2. Install the front brake caliper assembly
3. Install the wheel

VI. Rear brake pad lining

(I) Remove

△ Note To maintain wheel balance, before removing the

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tire, mark the relative positions of the wheel.

1. Remove the rear wheel refers to wheels.
2. Remove the rear brake caliper lining

1). Lower the parking brake.

2) Demolition two mounting bolts of rear caliper
positioning pin.

3) Flip rear caliper clamp body assembly.

△ Note avoid pulling the brake hose

4). Remove the inner and outer brake pad lining.

(II) Inspection

1. Check thickness of the brake pads friction plates

1). Check the thickness with the caliper scale lining. Brake
caliper lining standard thickness (front disc rear disc
models): 8mm rear brake caliper pad wear limit thickness
(front disc rear disc models): 2mm

△ Note that if the brake shoe thickness less than the

thickness of the wear limit, replace the brake caliper lining

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(III) Installation

1. Install the caliper lining

1). Mount the brake caliper friction disc to the brake
caliper mounting bracket.

△ Note install in accordance with the friction plate pad and

friction plate retaining ring direction

2) Install rear brake caliper assembly positioning pin
fixing bolts and tighten
Tightening torque 22 ~ 32N • m

3). Fix brake disc, tread the brake pedal until the brake
respond.

4) Check the rotation resistance of brakes.

2. Install the rear wheels

VII Rear brake caliper assembly

(I) Remove

1. Remove the wheels refers to wheels
2. Discharge brake fluid refer to brake fluid
3. Remove the rear brake caliper assembly

1). Lower the parking brake.

2) Remove the brake hose bolts and copper washers
connecting to the rear brake hose and the rear brake
caliper.

△ Note attention not to drop copper washer at both ends of

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the bolt

3) Demolition two mounting bolts connecting rear caliper
assembly and rear torsion beam assembly.

4) Remove fixing nuts and cards connecting rear brake
caliper assembly and rear parking brake drawing;
disengage the rear brake caliper assembly and rear parking
brake drawing.

5) Remove the rear brake caliper assembly.

(II) Installation

1. Install the rear brake caliper assembly

1). Place the rear caliper assembly to the mounting
position, pre tighten brake caliper mounting bracket bolts.

2). Tighten two mounting bolts connecting the rear caliper
assembly and torsion beam assembly.
Tightening torque 65 ~ 75N • m