Chery QQ6 (S21) / S12LHD. Manual — part 172

2. Preparations

Tools: Ratchet wheel, ratchet lever, 13#, 14#, 16#, 18#, 19#, 8#,

30# socket, 10#, 13#, 14#, 16# ring wrench, vice,

torque wrench, measure ruler..

Accessories: brake fluid

3. Notices

3.1 Please wear necessary labor protection supplies to avoid

accidents.

3.2 The brake liquid is one toxic liquid. In event of contact with the

skin or eyes due to carelessness, flush with a great amount of water

and if necessary call for medical treatment timely.

3.3 The scrapped brake liquid should be accommodated in the

container. It’s prohibited to drain it into the sewage system or stack

with other household garbage.

3.4 Do not depress the brake pedal nor move the vehicle during the

removal/installation operation.

3.5 Do not make the friction lining or brake disc come contact with

the oil substances, which will impair the braking effects.

4. Removal and Overhaul

4.1 Remove the protective cover from the tire rim with slotted

screwdriver.

4.2 Remove the tire fixing nuts with 19# torque wrench or vehicle

attached tool and remove the tire.

Torque: 110±10 Nm.

4.3 Lift the vehicle with elevator.

4.4 Remove the 2 nuts (upper and lower) from

the brake calliper and steering joint with 18# wrench.

4.5 Remove the nuts from brake hose with 13# wrench.

Notice: The brake liquid is one toxic liquid. Do not splash the brake

liquid to the clothes or skin during the removal of the brake hose.

Torque: 16±3 Nm.

4.6 Pull out the brake disc with hand.

4.7 Measure the thickness of friction lining. If below 3mm, replace

timely in pairs.

4.8 Remove the brake calliper and brake pump with 14# wrench.

4.9 Remove the dustproof seal and check for the damage of the

dustproof seal. If necessary, renew the dustproof seal. Clean the

contact surface of the brake piston and apply with one film of

silencing grease.

Notice: It's prohibited to make the dustproof seal come contact with

the silencing grease, which will cause the swelling of the dustproof

seal.

4.10 Remove the piston. Prepare one wood board to hold the piston

and place the wood board between the piston and the wall of the

brake calliper. Press out the piston with the compressed air carefully

through the connecting bore. Place the guard plate (such as hard

wood) at the notch of the brake calliper to protect the piston.

Notice: Do not hold the piston with fingers – danger of clamping!

The brake calliper piston is prohibited from removal at will and

should be removed/installed only by professionals or under the

guidance of the professionals.

4.11 Check the guide sleeve. The guide sleeve should move

smoothly and freely when pushed with hand. Replace the guide

sleeve in event of jamming or stiffness. Notice: Apply the

lubricating grease onto the guide sleeve during assembling.

4.12 Remove the seal ring carefully with the plastic needle, clean the

brake cylinder and components with alcohol and blow dry with

compressed air. Carefully check the surfaces of brake cylinder,

piston, and flange. It’s prohibited to conduct the machining process

on the brake cylinder and piston.

4.3 Installation of brake branch pump: Apply one film of brake

cylinder cream onto the cylinder body, plunger, and seal sleeve.

Attach the seal ring onto the circular groove at the rear of the brake

cylinder. Attach the dustproof seal ring onto the front circular groove

and press it in completely.

4.14 The area between the dustproof seal ring and the brake clamp

housing must be kept dry. It should be kept away from the brake

cylinder cream or the brake liquid, in order to ensure the correct

position of dustproof seal ring.

4.15 Secure the brake piston with the reinforcement parts available

in market and press it onto the dustproof seal ring slightly. Blow the

dustproof seal ring with compressed air (up to 3.0bar) to attach the

piston ring onto the piston.

Notice: Dip the dustproof seal ring and piston with brake

liquid to facilitate the passing of the seal ring.

4.16 (Checking of brake disc) Check the thickness of brake disc.

Replace the brake disc if the thickness is less than the min thickness.

Notice: The two brake discs at the same axle should be replaced at a

time. The friction linings must be replaced following the

replacement of the brake discs.

4.17 Check the max run-out of the end surface of brake disc with

dial gage. If above 0.03mm, replace it. (Provided that the brake disc

thickness is guaranteed, it may conduct the proper machining to

meet with the max run-out.)

4.18 Installation of other portions with reference to the Removal

Procedure.