Appearance

Friction material contaminated by oil and grease or brake fluid

Cause

The brake fluid overflows during maintenance or leaks from the brake caliper

Influence

• The vehicle may slip sideways during braking
  
• The braking performance will be decreased
  

Troubleshooting

• Find out the contamination source and fix it
  
• Replace with a new set of brake pads

Appearance

Friction materials of brake pads were heavily worn

Cause

• Brake pads generate high heat intermittently in short time
• The brake is violently applied in the breaking-in period of vehicle
  

Influence

The braking performance is reduced temporarily

Troubleshooting

• If the friction is slightly worn, no action needs to be taken
  
• If it is heavily worn, the brake pads should be replaced with a new set
  
• Check the brake disc

Appearance

Irregular wear on the edge of brake pad surface

Cause

The brake disc is worn irregularly, or the edge of brake disc is worn

Influence

• The braking efficiency will be affected
  
• Brake pads will be worn irregularly
• Noise and vibration will be generated in braking
  

Troubleshooting

Replace the brake disc and pads

Appearance

Backplate bent and broken

Cause

The backplate was not assembled or installed with excessive force

Influence

• The braking efficiency will be affected
  
• Brake pads will be worn irregularly
  
• Noise and vibration will be generated in braking
  

Troubleshooting

Replace with a new set of brake pads

Appearance

One or several brake pads is excessively worn

Cause

The locating pin or piston of brake caliper is stuck

Influence

• The vehicle may slip sideways during braking
  
• The brake pad will be worn irregularly, excessively and quickly
  

Troubleshooting

• Carry out maintenance for guide rails and pistons of all brake calipers
  
• Check and replace the brake pads, and replace if necessary

Appearance

Rust in friction material and back plate

Cause

When the backplate bends during braking, the brake pads will be stuck in the bracket of caliper and crack the friction material. The rust will aggravate the cracking of friction material and make it fall off the back plate

Influence

• Noise will be generated in braking, and the brake pedal needs to be applied with greater force but the speed reduction becomes slower
• Once the friction material falls off, the brake becomes entirely ineffective
  

Troubleshooting

• Replace with a new set of brake pads
• Clean and maintain the brake caliper to make sure the brake pads can be easily installed into the brake caliper

Appearance

Brake pads worn irregularly or tapered

Cause

• The guide rail of brake caliper seizes up or the caliper deforms
• Excessive clearance between the brake calipers
  

Influence

• Brake pads will be prematurely worn and noise will be generated in braking
  
• The braking force becomes uneven
  

Troubleshooting

Replace with a new set of brake pads and carry out maintenance and repair for the brake caliper

Note: Brake pads of some vehicles are specially tapered in design. Please refer to the applicable vehicle models to determine if the taper exceeds the allowable range

Appearance

Brake pads damaged

Cause

• In a set of brake pads, any brake pad is different from others and they need to be installed inside or outside the caliper
  
• If the brake is installed improperly, brake pads will be damaged
  

Influence

• Brake pads will be damaged
  
• The braking performance will be decreased
  

Troubleshooting

Replace with a new set of brake pads by reference to the drawing as indicated by the manufacturer

Appearance

Scratches of irregular wear on the surface of brake pad

Cause

• The brake pad is not in full contact with the disc
  
• The disc is scratched by dust or excessive wear
• It may occurs when new brake pads is installed on the worn disc
  

Influence

• Squeal noise with vibration will be generated in braking
  
• The braking efficiency will be affected
  

Troubleshooting

Replace both the brake pads and disc

Appearance

Cracks on the edge of brake pad surface

Cause

Brake pads get struck in the caliper, fail to separate from the brake disc and generate high temperature

Influence

Brake pads may be worn on the surface and thus the braking performance deteriorated

Troubleshooting

• Find out the reason results in the caliper being stuck
  
• Carry out maintenance for the caliper
  
• Replace with a new set of brake pads

Appearance

Small cracks in the center of brake pad

Cause

Cracks generally occur on brake pads when the caliper gets stuck. The backplate is bent by the caliper, which results in cracking of friction material

Influence

• Noise will be generated in braking
  
• Brake pads will be worn irregularly. The vehicle may slip sideways during braking
• One side of vehicle may overheat
  

Troubleshooting

Carry out maintenance and repair for the caliper. Replace with a new set of brake pads

Appearance

Metal particles inset on the friction surface

Cause

In normal braking, these particles can generally be removed. But in very humid environment, these particles may be quenched and quickly cooled into solids attached on the surface of brake pads

Influence

Normally, these particles will not adversely affect the brake performance. But in extreme conditions, they may damage the brake disc or result in squeal noise during braking

Troubleshooting

Replace the brake disc and pads if necessary in extreme conditions

Appearance

Excessive wear of friction material

Cause

Brake pads are not regularly inspected for wear or the brake is not properly maintained

Influence

• The vehicle may slip sideways during braking
  
• The brake disc may be damaged
  
• Squeal noise and  other noises will be generated in braking
  

Troubleshooting

• Check if the disc is damaged
  
• If so, replace both the pads and discs

Appearance

Friction material scorched or burnt partially (white outer edge of brake pads)

Cause

Brake pads overheat for a long time due to excessive use, or dragging occurs between the brake pad and disc

Influence

• The initial braking performance will be reduced
  
• The friction material will be greatly scorched, resulting in abnormal wear
  
• The friction material becomes brittle, resulting in fragments and cracks
  
• Find out the reason resulting in overheating of brake pads
  
• If not heavily worn, the brake pads will not malfunction in normal use
  

Troubleshooting

If heavily worn, the brake pads should be replaced with a new set