Scheme 4
Operation inspection
- With the engine stopped, depress the brake pedal several times.
- With the brake pedal depressed, start the engine.
- If the brake pedal moves down slightly immediately after starting the engine, the unit is normal.
Brake Judder Repair Hints Description
- Brake judder concern has the following 3 characteristics
Steering wheel vibration
- Steering wheel vibrates in the rotation direction. This characteristic is most noticeable when applying brakes at a vehicle speed of 100-140 km/h {62.1-86.8 mph} .
Floor vibration
- When applying the brakes, the vehicle body shakes back and forth. The seriousness of the shaking is not influenced by vehicle speed.
Brake pedal vibration
- When applying brakes, a pulsating force tries to push the brake pad back. The pulsation is transmitted to the brake pedal.
- The following are the main possible causes of brake judder
Due to an excessive runout (side-to-side wobble) of the disc plate, the thickness of the disc plate is uneven.
- If the runout is more than 0.05 mm {0.002 in} at the position 10 mm {0.39 in} from the disc plate edge, uneven wear occurs on the disc plate because the pad contacts the plate unevenly.
- If the runout is less than 0.05 mm {0.002 in} , uneven wear does not occur.
The disc plate is deformed by heat.
- Repeated panic braking may raise the temperature in some portions of disc plate by approx. 1, 000°C {1, 832°F} . This results in a deformed disc plate.
Due to corrosion, the thickness and friction coefficient of disc plate change.
- If a vehicle is parked in damp conditions for a long time, corrosion occurs on the friction surface of disc plate.
- The thickness of corrosion is uneven and sometimes appears like a wave pattern, which changes the friction coefficient and causes a reaction force.
Scheme 5
Scheme 6
- To secure the disc plate and the hub, insert the washer (thickness 10 mm {0.39 in} , inner diameter more than 12 mm {0.47 in} ) between each hub bolt and the hub nut, then tighten all the hub nuts. NOTE: The component parts of the SST (49 B017 001 or 49 G019 003) can be used as a suitable washer.
- After tightening all the hub nuts to the same torque, put the dial gauge on the friction surface of disc plate 10 mm {0.12-0.28 in} from the disc plate edge.
- Rotate the disc plate one time and measure the runout. Front disc plate runout limit 0.05 mm {0.002 in}
Scheme 7
- Clean the disc plate-to-pad friction surface using a brake cleaner.
- Measure the points indicated in the illustration using a caliper (micrometer).
- Subtract the minimum value from the maximum, and if the result is not within specification, machine the disc plate using a lathe. Thickness variation limit 0.015 mm {0.00059 in} WARNING: Do not exceed minimum disc plate thickness.
- Brake judder concern has the following 3 characteristics
Steering wheel vibration
- Steering wheel vibrates in the rotation direction. This characteristic is most noticeable when applying brakes at a vehicle speed of 100-140 km/h {62.1-86.8 mph} .
Floor vibration
- When applying the brakes, the vehicle body shakes back and forth. The seriousness of the shaking is not influenced by vehicle speed.
Brake pedal vibration
- When applying brakes, a pulsating force tries to push the brake pad back. The pulsation is transmitted to the brake pedal.
- The following are the main possible causes of brake judder
Due to an excessive runout (side-to-side wobble) of the disc plate, the thickness of the disc plate is uneven.
- If the runout is more than 0.05 mm {0.002 in} at the position 10 mm {0.39 in} from the disc plate edge, uneven wear occurs on the disc plate because the pad contacts the plate unevenly.
- If the runout is less than 0.05 mm {0.002 in} , uneven wear does not occur.
The disc plate is deformed by heat.
- Repeated panic braking may raise the temperature in some portions of disc plate by approx. 1, 000°C {1, 832°F} . This results in a deformed disc plate.
Due to corrosion, the thickness and friction coefficient of disc plate change.
- If a vehicle is parked in damp conditions for a long time, corrosion occurs on the friction surface of disc plate.
- The thickness of corrosion is uneven and sometimes appears like a wave pattern, which changes the friction coefficient and causes a reaction force.
Scheme 8
Scheme 9
- To secure the disc plate and the hub, insert the washer (thickness 10 mm {0.39 in} , inner diameter more than 12 mm {0.47 in} ) between each hub bolt and the hub nut, then tighten all the hub nuts. NOTE: The component parts of the SST (49 B017 001 or 49 G019 003) can be used as a suitable washer.
- After tightening all the hub nuts to the same torque, put the dial gauge on the friction surface of disc plate 10 mm {0.39 in} from the disc plate edge.
- Rotate the disc plate one time and measure the runout. Rear disc plate runout limit 0.05 mm {0.002 in}
Scheme 10
- Clean the disc plate-to-pad friction surface using a brake cleaner.
- Measure the points indicated in the illustration using a caliper (micrometer).
- Subtract the minimum value from the maximum, and if the result is not within specification, machine the disc plate using a lathe. Thickness variation limit 0.015 mm {0.00059 in} WARNING: Do not exceed minimum disc plate thickness.