Downloaded from www.Manualslib.com manuals search engine DIAGNOSIS & TESTING
Diagnostic Help
Brake diagnosis involves determining if the concern is related to a mechanical, hydraulic, electrical or vacuum oper-
ated component.
NOTE :
The brake reservoir fluid level will decrease in proportion to normal lining wear.
NOTE :
Brake fluid tends to darken over time. This is normal and should not be mistaken for contamination.
Preliminary Brake Check:
•Check the condition of the tires and wheels. Damaged wheels and worn, damaged or under inflated tires can
cause a pull, shudder, vibration and a condition similar to brake grab.
• If a complaint was based on noise while braking, check the suspension components. Jounce the front and the
rear of vehicle and listen for anything that might be caused by a loose, worn or damaged suspension or steer-
ing component.
• Inspect the brake fluid level and condition.
1. If the fluid level is abnormally low, look for any evidence of leaks at the calipers, brake lines, master cyl-
inder and at the Antilock Brake System (ABS) Hydraulic Control Unit (HCU).
2. If the fluid appears to be contaminated, drain a sample to examine.
• The system will have to be flushed if the fluid is separated into layers, or contains a substance other than
brake fluid. The system seals, cups, hoses, master cylinder and HCU will also have to be replaced after flush-
ing. Use clean brake fluid to flush the system.
• Check the parking brake operation. Verify free movement and full release of the cables and the lever. Also note
if the vehicle was being operated with the parking brake partially applied.
• Check the brake pedal operation. Verify that the pedal does not bind and has adequate free play. If the pedal
lacks free play, check the pedal and the power booster for looseness or for a binding condition. DO NOT road
test the vehicle until the condition is located and corrected.
• Check the vacuum booster check valve and vacuum supply hose.
• If the preliminary checks appear to be OK, road test the vehicle.
Brake Noise
CONDITION POSSIBLE CAUSES CORRECTION
Disc Brake Chirp · Excessive brake rotor runout.
· Small particles· Diagnose and correct as
necessary.
Disc Brake Rattle Or Clunk · Broken or missing spring clips.
· Caliper guide pin bolts loose.
· Missing abutment shims.
· Small metal particles· Replace brake pads.
· Tighten guide pin bolts.
· Replace missing abutment shims.
Disc Brake Squeak At Low Speed
(While Applying Light Brake Pedal
Effort) · Brake shoe linings.
· Replace brake pads.
Scraping Or Whirring · ABS wheel speed sensor hitting
tone wheel.· Inspect, correct or replace faulty
component(s).
12
12–7Chery Automobile Co., Ltd.
Downloaded from www.Manualslib.com manuals search engine Braking Concerns
CONDITIONPOSSIBLE CAUSES CORRECTION
Excessive Pedal Effort · Obstruction of brake pedal.
· Low power brake booster assist.
· Glazed brake pads.
· Brake pad lining transfer to brake
rotor.· Inspect, remove or move
obstruction.
· Refer to Power Brake Booster in
this section.
· Resurface or replace brake rotors
as necessary. Replace brake pads.
· Resurface or replace brake rotors
as necessary. Replace brake pads.
Excessive Pedal Effort (Hard Pedal
Unable To Lock-Up Wheels) · Power brake booster runout
(vacuum assist).· Check booster vacuum hose and
engine tune for adequate vacuum
supply.
Excessive Pedal Travel (Vehicle
Stops OK) · Air in brake lines.
· Bleed brakes.
Pedal Pulsates/Surges During
Braking · Disc brake rotor has excessive
thickness variation.· Isolate condition as rear or front.
Resurface or replace brake rotors as
necessary.
Pedal Is Spongy · Air in brake lines.· Bleed brakes.
Vehicle Pulls To Right Or Left On
Braking · Frozen brake caliper piston.
· Contaminated brake pad/shoe
lining (most likely front lining).
· Pinched brake lines.
· Leaking piston seal.
· Suspension problem.· Replace frozen piston or caliper.
Bleed brakes.
· Inspect and clean, or replace
pads/shoes. Repair source of
contamination.
· Replace pinched line.
· Replace piston seal or brake
caliper.
· See the Suspension section.
Parking Brake - Excessive Handle
Travel · Rear brakes out of adjustment.· Adjust rear parking brake shoes on
vehicles with rear disc brakes.
DIAGNOSIS & TESTING
12–8Chery Automobile Co., Ltd.
Downloaded from www.Manualslib.com manuals search engine ON-VEHICLE SERVICE
Brake Bleeding
Brake Bleeding Information
WARNING!
When bleeding the brake system, wear safety glasses. A clear bleed tube must be attached to the bleeder
screws and submerged in a clear container filled partially with clean brake fluid. Direct the flow of brake fluid
away from yourself and the painted surfaces of the vehicle. Brake fluid at high pressure may come out of the
bleeder screws when opened.
CAUTION:
Before removing the master cylinder cap, wipe it clean to prevent dirt and other foreign matter
from dropping into the master cylinder reservoir. Use brake fluid or an equivalent from a fresh,
tightly sealed container. Brake fluid must conform to DOT 4 specifications.
NOTE :
During the brake bleeding procedure, be sure the brake fluid level remains close to theMAXlevel in the master
cylinder fluid reservoir. Check the fluid level periodically during the bleeding procedure and add brake fluid as
required.
NOTE :
Do not pump the brake pedal at any time while having a bleeder screw open during the bleeding process. This will
only increase the amount of air in the system and make additional bleeding necessary. Do not allow the master
cylinder reservoir to run out of brake fluid while bleeding the system. An empty reservoir will allow additional air into
the brake system. Check the fluid level frequently and add fluid as needed. The following wheel circuit sequence for
bleeding the brake hydraulic system should be used to ensure adequate removal of all trapped air from the hydraulic
system.
Brake Bleeding Procedure
The following wheel circuit sequence for bleeding the brake hydraulic system should be used to ensure adequate
removal of all trapped air from the hydraulic system:
• Left rear wheel
• Right front wheel
• Right rear wheel
• Left front wheel
Manual Brake Bleeding
NOTE :
To bleed the brakes manually, the aid of a helper will be required.
Fill the brake master cylinder reservoir to the proper level with brake fluid.
12
12–9Chery Automobile Co., Ltd.
Downloaded from www.Manualslib.com manuals search engine NOTE :
Never allow the brake master cylinder to empty of brake fluid while bleeding the brake system.
Attach a clear plastic hose to the bleeder screw and
feed the hose into a clear jar containing enough fresh
brake fluid to submerge the end of the hose.
1. Turn the ignition switch off.
2. Have a helper pump the brake pedal three or four times and hold it in the down position.
3. With the pedal in the down position, open the bleeder screw at least one full turn.
4. Once the brake pedal has dropped, close the bleeder screw. After the bleeder screw is closed, release thebrake pedal.
5. Repeat the above steps until all trapped air is removed from that wheel circuit (usually four or five times).
6. Bleed the remaining wheel circuits in the same manner until all air is removed from the brake system. Monitor the fluid level in the master cylinder reservoir to make sure it does not go dry.
7. Check and adjust brake fluid level to the MAXmark.
8. Check the brake pedal travel. If pedal travel is excessive or has not been improved, some air may still be trapped in the system. Re-bleed the brakes as necessary.
9. Test drive the vehicle to verify the brakes are operating properly and pedal feel is correct.
Pressure Brake Bleeding
NOTE :
Follow pressure bleeder manufacturer’s instructions for use of pressure bleeding equipment.
Fill the brake master cylinder reservoir to the proper level with brake fluid.
Attach the pressure bleeding equipment to the master cylinder.
NOTE :
Never allow the brake master cylinder to empty of brake fluid while bleeding the brake system.
Attach a clear plastic hose to the bleeder screw and
feed the hose into a clear jar containing enough fresh
brake fluid to submerge the end of the hose.
1. Turn the ignition switch off.
2. Open the bleeder screw at least one full turn or more to obtain a steady stream of brake fluid.
3. After approximately 120-240 ml of fluid has been bled through the brake circuit and an air-free flow is main- tained in the clear plastic hose and jar, close the bleeder screw.
4. Repeat this procedure at all the remaining bleeder screws.
5. Check and adjust brake fluid level to the MAXmark on the reservoir.
ON-VEHICLE SERVICE
BESM120001
BESM120001
12–10Chery Automobile Co., Ltd.
Downloaded from www.Manualslib.com manuals search engine 6. Check the brake pedal travel. If pedal travel is excessive or has not been improved, some air may still betrapped in the system. Re-bleed the brakes as necessary.
7. Test drive the vehicle to verify the brakes are operating properly and pedal feel is correct.
Master Cylinder - LHD
Description
The master cylinder body is an anodized aluminum casting. It is located at the left side of the engine room. It has a
machined bore to accept the master cylinder pistons and also has threaded ports with seats for hydraulic brake tube
connections. The master cylinder has the brake fluid reservoir mounted on top of it and supplies brake fluid to the
master cylinder as required. On manual transaxle equipped vehicles, the brake fluid reservoir also feeds the clutch
hydraulic circuit. The reservoir is made of clear plastic and it houses the brake fluid level switch.
Operation
When the brake pedal is pressed, the master cylinder pistons apply brake pressure through the chassis brake tubes
to each brake assembly. The brake fluid reservoir supplies the brake hydraulic system with the necessary fluid to
operate properly.
Removal & Installation
CAUTION:
The vacuum in the power brake booster must be pumped down before removing the master cyl-
inder to avoid damaging the master cylinder and to prevent the booster from sucking in any con-
tamination. This can be done by pumping the brake pedal while the engine is not running until a
firm brake pedal is achieved.
1. Turn the ignition switch off.
2. Siphon out as much brake fluid as possible from the master cylinder.
3. With the engine off, pump the brake pedal 4-5 strokes until the pedal feel is firm.
4. Disconnect the negative battery cable.
5. Disconnect the brake fluid level switch electrical connector in the master cylinder brake fluid reservoir.
6. Disconnect the brake tubes (1) at the master cylin- der outlet ports. Install plugs at all of the open
brake tube outlets on the master cylinder.
(Tighten: Brake tube nuts to 10 N·m)
ON-VEHICLE SERVICE
BESM120006
12
12–11Chery Automobile Co., Ltd.
Downloaded from www.Manualslib.com manuals search engine 9. Disconnect the brake tubes (1) and remove thenuts (2) attaching the master cylinder to the power
brake booster.
(Tighten: Master cylinder mounting nuts to 23 N·m)
10. Slide the master cylinder straight out of the power brake booster.
11. Installation is in the reverse order of removal.
NOTE :
After installation, bleed the master cylinder or bleed the entire brake system as necessary.
Power Brake Booster - LHD
Description
The power brake booster is mounted in the engine compartment on the left side of the dash panel. The master
cylinder is bolted to the front of the booster.
Operation
A vacuum line connects the check valve to engine source vacuum. The booster input rod extends through the dash
panel and connects to the brake pedal.
Removal & Installation
CAUTION:
The vacuum in the power brake booster must be pumped down before removing the master cyl-
inder to avoid damaging the master cylinder and to prevent the booster from sucking in any con-
tamination. This can be done by pumping the brake pedal while the engine is not running until a
firm brake pedal is achieved.
1. Remove the master cylinder (See Master Cylinder Removal & Installation in Section 12 Brakes).
ON-VEHICLE SERVICE
LTSM120041
LTSM120005
12–14Chery Automobile Co., Ltd.
Downloaded from www.Manualslib.com manuals search engine 2. Remove the spring-type cotter pin (2) and clevispin (1) from the brake booster rod (3).
3. Remove the nuts and bolts (1) attaching the power brake booster to the brake pedal bracket.
(Tighten: Brake pedal/Power brake booster mount-
ing nuts and bolts to 25 N·m)
4. Remove the brake pedal bracket.
5. Disconnect the vacuum hose (1) from the check valve on the power brake booster.
6. Slide the power brake booster (1) forward until its mounting studs clear the dash panel, then remove
it through the engine compartment.
7. Installation is in the reverse order of removal.
ON-VEHICLE SERVICE
BESM120009
LTSM120006
LTSM120004
BESM120028
12
12–15Chery Automobile Co., Ltd.
Downloaded from www.Manualslib.com manuals search engine Power Brake Booster - RHD
Description
The power brake booster is mounted in the engine compartment on the right side of the dash panel. The master
cylinder is bolted to the front of the booster.
Operation
A vacuum line connects the check value to engine source vacuum. The booster input rod extends through the dash
panel and connects to the brake pedal.
Removal & Installation
CAUTION:
The vacuum in the power brake booster must be pumped down before removing the master cyl-
inder to avoid damaging the master cylinder and to prevent the booster from sucking in any con-
tamination. This can be done by pumping the brake pedal while the engine is not running until a
firm brake pedal is achieved.
1. Remove the master cylinder (See Master Cylinder Removal & Installation in Section 12 Brakes).
2. Remove the spring-type cotter pin (2) and clevispin (1) from the brake booster rod (3).
3. Remove the nuts and bolts (1) attaching the power brake booster to the brake pedal bracket.
(Tighten: Brake pedal/Power brake booster mount-
ing nuts and bolts to 25 N·m)
4. Remove the brake pedal bracket.
ON-VEHICLE SERVICE
BESM120009
LTSM120006
12–16Chery Automobile Co., Ltd.