Common faults and maintenance methods of braking s

2022-10-20
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Common faults and maintenance methods of micro car braking system

the braking system is one of the most important safety parts of the car. Once there is a fault, the consequences will be unimaginable. The common faults and maintenance methods of micro car braking system are as follows:

first, poor braking or failure

1 The brake pipe (such as the joint) leaks or blocks, the brake fluid is insufficient, and the brake oil pressure drops and fails. Regularly check the brake pipeline to eliminate leakage, add brake fluid and dredge the pipeline

2. The air entering the brake pipe makes the brake slow, the brake pipeline is heated, and the residual pressure in the pipe is too small, resulting in the gasification of the brake fluid and bubbles in the pipeline. Because the gas is compressible, the braking torque decreases during braking. During maintenance, exhaust the air in the brake wheel cylinder and pipe and add enough brake fluid

3. Improper brake clearance. The clearance between the working surface of the brake friction pad and the working surface of the inner wall of the brake drum is too large, and the stroke of the pump piston is too large during braking, resulting in slow braking and reduced braking torque. During maintenance, adjust the brake clearance comprehensively according to the specifications, that is, use a flat head screwdriver to pull the ratchet from the high-speed hole, fully open the brake drum, eliminate the clearance, and then return the ratchet to 3-6 teeth to obtain the specified clearance

4. The brake drum has poor contact with the friction lining, the brake shoe is deformed or the roundness of the brake drum exceeds 0.5mm, resulting in poor contact between the friction lining and the brake drum, and the brake friction torque decreases. If this phenomenon is found, it must be bored or corrected and repaired. The diameter of the brake drum after boring shall not be greater than 220mm, otherwise it shall be replaced with a new part

5. The brake friction plate is polluted by oil dirt or soaked in water, and the friction coefficient decreases sharply, causing brake failure. During maintenance, remove the friction plate, clean it with gasoline, and heat and bake the blowtorch to make the oil in the infiltrated plate leak out. If the oil leakage is severely punished, the new plate must be replaced. For the wetted friction plate, continuous braking can be used to generate heat energy to evaporate the water and restore its friction coefficient

6. The leather cups (or other parts) of the brake master cylinder and slave cylinder are damaged, and the brake pipeline cannot generate the necessary internal pressure, and the oil leaks, resulting in poor braking. The cups of the brake master cylinder and slave cylinder should be removed and inspected in time, and the worn and damaged parts should be replaced

II. Braking unilateral

1 The braking time of the left and right brakes of the coaxial is inconsistent, which is mostly caused by the uneven braking clearance or the difference in contact area of the brakes on both sides. During braking, one side of the friction plate contacts the brake drum for braking, while the other side is not synchronized due to large clearance and delayed contact between the friction plate and the brake drum. In case of this phenomenon, the brake clearance of the left and right wheels can be readjusted according to the specifications

2. The braking torque of the brakes on both sides of the coaxial line is different, resulting in different vehicle speeds and unequal straight-line travel distances, resulting in unilateral braking. This is usually caused by the oil leakage of the brake wheel cylinder on one side, the serious oil contamination of the brake friction pads, the difference of the motorcycle coefficient or the unequal pressure of the left and right tires. Gasoline can be used to clean the friction plate, high-speed tire pressure, repair the leakage, and eliminate them respectively

3. The car slides to the side automatically without stepping on the brake plate. This is mostly caused by the deformation of one side of the front suspension, the deformation of the front suspension underbody, the serious decline of the spring force of the front suspension coil, and the mutual interference or incongruity of relevant parts such as the frame when the vehicle is braking. In case of the above situation, find out the cause and repair it

4. When braking, the wheel automatically turns to one side and deviates. This is mainly caused by the different roughness of the working surface of the brake drums and friction pads on both sides, or the blockage of the joint in the air of the brake pipeline on one side. The root causes should be found and repaired respectively

5. The left and right tire pressures are uneven, resulting in distance deviation. The inflation of the left and right tires must be consistent, otherwise the actual rotation ESC of the wheels on both sides is different from the chemical resistance, the dynamic radius is different, and the straight-line distance is different, resulting in side slip. All tires must be inflated according to the specified standards

6. In addition to the above reasons, there are wheel alignment errors and different wear of left and right tires, so the resistance difference between the road surface and the left and right wheels will also cause side slip. In this case, find out the reason. 1. Make sure that the refrigeration tank is filled with refrigeration materials, and then adjust or replace parts according to the specifications

III. braking noise

1 The brake drum is out of round, its roundness error is more than 0.5mm, and the working surface of the brake drum is deformed by 9 ellipses). When braking, the friction plate and the brake drum will collide instantly, and a sharp impact sound will be sent out at the same time. During maintenance, remove the brake drum, carry out boring according to the specifications and standards, and verify the balance performance, and control the imbalance within

2. When the surface of the brake friction plate is too smooth, the friction coefficient is small, and the braking pressure is large, the friction noise will be generated when the smooth surface is worn. Or foreign matters are inserted between the friction pairs to squeeze the friction surface, and friction noise will also appear by polysulfide building sealant jc483 (9) 2. During maintenance, remove the brake drum, remove foreign matters, polish the friction plate with coarse sandpaper, and make it cooperate with the friction pair with a contact area of more than 70%

3. The brake friction plate is seriously worn, and the surface appears transverse groove and irregular shape. During braking, it cannot fully and effectively fit with the brake drum, or the brake support plate changes, which destroys the coaxiality between the drum and the plate, and local friction and collision lead to noise. During maintenance, replace the friction plate and correct the brake support plate

4. The front wheel bearing is damaged, and the surface of the raceway and the ball reappears pits, grooves and even cracks, which will cause abnormal noise during braking. This noise can be reduced by replacing the front axle head bearing

IV. brake drum heating

1 The brake clearance is too large and the free stroke of the pedal is too small. When the brake pedal is released, the braking force is not completely released, and it is in a state of friction for a long time; It is difficult to start, weak to drive, and feel hot by touching the surface of the wheel drum for a long time. In case of any situation, the high-speed braking clearance shall be reset according to the specification

2. The reason why the brake handle is not fully released is that the friction pair is in the friction state for a long time due to improper high-speed driving or negligence in operation. If necessary, drive at high speed according to the specifications

3. The heat generated by braking causes the return spring to be heated and deformed, and the elastic force decreases or disappears. If the brake friction plate assembly and time position cannot be guaranteed, the brake cannot be completely released in time, causing the brake drum to heat up. The fault can be eliminated by repairing or replacing the return spring in time

v. parking brake failure

the common cable or jacket is rusted, the traction spring is broken, falls off or the elasticity disappears, resulting in the inflexible pulling of the parking brake control cable or brake cable in its jacket, so the hand brake cannot be released and the work fails. Check whether the brake control cable and the surface of brake system components are damaged, whether the handle control action is flexible and free of stagnation, and whether the cable connector and fixed parts are loose and damaged. During maintenance, fill the cable with grease for lubrication, or replace the damaged parts, and deal with them again according to the repair specifications

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