Brake System: Precaution
WARNING: This page is about a different car, the 2008 Lexus LS 600hL. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION:
- While the battery is connected, even if the power switch is OFF, the brake control system activates when the brake pedal is depressed or the door courtesy switch turns on. Therefore during servicing of the brake system components, do not operate the brake pedal or open/close the doors while the battery is connected.
- The intelligent tester or Techstream must be used when bleeding air. If not used, the air bleeding will be incomplete, which is hazardous and may lead to an accident.
NOTE:
for BRAKE SYSTEM
- Care must be taken to replace each part properly as it could affect the performance of the brake system and result in a driving hazard. Replace the parts with those having the same part number or equivalent.
- It is very important to keep parts and the work area clean when repairing the brake system.
- If the vehicle is equipped with a mobile communication system, refer to the precaution in the INTRODUCTION article (see REPAIR INSTRUCTION ).
- Care must be taken when using magnets as they could affect the performance of the speed sensors.
- Since the brake line is classified as one of the critical safety related parts, be sure to disassemble the components if a brake fluid leak is found. If any abnormality is found, replace the component with a new one.
- When removing brake components, cover the brake tube connections to prevent foreign matter such as dust or dirt from entering the tubes.
- Do not damage or deform the brake tubes when removing or installing them.
- When installing a brake tube or flexible hose, ensure that they are free from twisting or bending.
- If the cap of the flexible hose does not match the groove on the bracket, twist the hose slightly to insert it.
- Flexible hoses must be free from absorber oil, grease, etc.
- When installing a brake tube to a plastic clamp, ensure that the brake tube is not loose or being pinched.
- Do not reuse a clip or plastic clamp removed from a flexible hose.
- After installing a brake tube and flexible hose, ensure that they do not interfere with any other components.
- Do not allow brake fluid to adhere to any painted surface such as the vehicle body. If brake fluid leaks onto any painted surface, immediately clean it off.
- Follow these procedures when disconnecting the flexible hose and brake tube.
- Remove the clip.
- Hold the flexible hose with a wrench. Using a union nut wrench, disconnect the brake tube without deforming the tube.
- Follow these procedures when connecting the flexible hose and brake tube.
- Hold the flexible hose with a wrench. Using a union nut wrench, connect the brake tube without deforming the tube.
- Install a new clip.
- Connect the brake tube and 2-way:
- Support the 2-way to prevent deformation of the brake tube and connect the brake tube to the 2-way with a union nut wrench.
- Support the 2-way to prevent deformation of the brake tube and install the bolt to fix the 2-way to the body.
NOTE:
for BLEEDING:
- Refer to the intelligent tester or Techstream operator's manual for further details.
- Move the shift lever to the P position and apply the parking brake before bleeding the brakes.
- Add brake fluid to keep the level between the MIN and MAX lines of the reservoir while bleeding the brakes.
- As brake fluid may overflow when bleeding air, do not place the fluid can on the reservoir filler opening.
- If the brake accumulator pump operates while air remains inside the No. 2 brake actuator hose, air will enter the brake accumulator pump, resulting in difficulty in bleeding. Keep the 2 brake accumulator pump connectors disconnected before bleeding.
- The brake accumulator pump and brake actuator solenoid can be operated by the driver even if the power switch is OFF.
- Although a buzzer may sound due to declined accumulator pressure during bleeding, continue bleeding.
- If DTCs indicating a malfunction in the ABS motor relay or pressure sensor are stored after bleeding, clear the DTCs after bleeding.
HINT
- Air bleeding with the intelligent tester or Techstream cannot be performed when the power switch is ON (IG) or when the parking brake is not operating (electric parking brake operation signal is not input into skid control ECU).
- While performing air bleeding, a display and navigation assembly (with HDD navigation system) or multi-display (without HDD navigation system) malfunction warning is displayed. However, there is no malfunction. After performing air bleeding, erase the warning using the tester's menus.
Bleeding work list
BLEEDING WORK LIST
| Item | Required Work | Work procedure |
|---|---|---|
| Brake fluid (replacement) | ◦ | Work to be performed after replacement |
| - | 1 Using intelligent tester or Techstream, perform accumulator zero down | |
| - | 2 Disconnect the 2 brake accumulator pump connectors | |
| ◦ | 3 Add brake fluid into the reservoir | |
| ◦ | 4 Using intelligent tester or Techstream, perform "DISABLE BRAKE CONTROL" | |
| ◦ | 5 Bleed the front brake system (FL, FR) | |
| ◦ | 6 Using intelligent tester or Techstream, cancel "DISABLE BRAKE CONTROL" | |
| - | 7 Connect the 2 brake accumulator pump connectors | |
| - | 8 Bleed the pump suction system (RR) | |
| ◦ | 9 Using intelligent tester or Techstream, perform "DISABLE BRAKE CONTROL" | |
| ◦ | 10 Bleed the rear brake system (RL, RR) | |
| ◦ | 11 Using intelligent tester or Techstream, cancel "DISABLE BRAKE CONTROL" | |
| - | 12 Using intelligent tester or Techstream, perform accumulator zero down | |
| ◦ | 13 Check and adjust the brake fluid level in the reservoir to the MAX level | |
| ◦ | 14 Clear the DTCs | |
| - | 15 Perform linear valve offset learning | |
| ◦ | 16 Check for DTC | |
| - | 17 Using intelligent tester or Techstream, check the accumulator pressure sensor output voltage | |
| Air bleeding (no part replacement) | ◦ | 1 Using intelligent tester or Techstream, perform accumulator zero down |
| ◦ | 2 Disconnect the 2 brake accumulator pump connectors | |
| ◦ | 3 Add brake fluid into the reservoir | |
| ◦ | 4 Using intelligent tester or Techstream, perform "DISABLE BRAKE CONTROL" | |
| ◦ | 5 Bleed the front brake system (FL, FR) | |
| ◦ | 6 Using intelligent tester or Techstream, cancel "DISABLE BRAKE CONTROL" | |
| ◦ | 7 Connect the 2 brake accumulator pump connectors | |
| ◦ | 8 Bleed the pump suction system (RR) | |
| ◦ | 9 Using intelligent tester or Techstream, perform "DISABLE BRAKE CONTROL" | |
| ◦ | 10 Bleed the rear brake system (RL, RR) | |
| ◦ | 11 Using intelligent tester or Techstream, cancel "DISABLE BRAKE CONTROL" | |
| ◦ | 12 Using intelligent tester or Techstream, perform accumulator zero down | |
| ◦ | 13 Check and adjust the brake fluid level in the reservoir to the MAX level | |
| ◦ | 14 Clear the DTCs | |
| ◦ | 15 Perform linear valve offset learning | |
| ◦ | 16 Check for DTC | |
| ◦ | 17 Using intelligent tester or Techstream, check the accumulator pressure sensor output voltage | |
|
◦ | Work to be performed before replacement |
| ◦ | 1 Using intelligent tester or Techstream, perform accumulator zero down | |
| ◦ | 2 Disconnect the 2 brake accumulator pump connectors | |
| ◦ | Work to be performed after replacement | |
| ◦ | 1 Using intelligent tester or Techstream, perform accumulator zero down | |
| ◦ | 2 Disconnect the 2 brake accumulator pump connectors | |
| ◦ | 3 Add brake fluid into the reservoir | |
| ◦ | 4 Using intelligent tester or Techstream, perform "DISABLE BRAKE CONTROL" | |
| ◦ | 5 Bleed the front brake system (FL, FR) | |
| ◦ | 6 Using intelligent tester or Techstream, cancel "DISABLE BRAKE CONTROL" | |
| ◦ | 7 Connect the 2 brake accumulator pump connectors | |
| ◦ | 8 Bleed the pump suction system (RR) | |
| ◦ | 9 Using intelligent tester or Techstream, perform "DISABLE BRAKE CONTROL" | |
| ◦ | 10 Bleed the rear brake system (RL, RR) | |
| ◦ | 11 Using intelligent tester or Techstream, cancel "DISABLE BRAKE CONTROL" | |
| ◦ | 12 Using intelligent tester or Techstream, perform accumulator zero down | |
| ◦ | 13 Check and adjust the brake fluid level in the reservoir to the MAX level | |
| ◦ | 14 Clear the DTCs | |
| ◦ | 15 Perform linear valve offset learning | |
| ◦ | 16 Check for DTC | |
| ◦ | 17 Using intelligent tester or Techstream, check the accumulator pressure sensor output voltage | |
| Front brake (removal, installation, and disassembly) Rear brake (removal, installation, and disassembly) |
- | 1 Using intelligent tester or Techstream, perform accumulator zero down |
| - | 2 Disconnect the 2 brake accumulator pump connectors | |
| ◦ | 3 Add brake fluid into the reservoir | |
| ◦ | 4 Using intelligent tester or Techstream, perform "DISABLE BRAKE CONTROL" | |
| ◦ | 5 Bleed the front brake system (FL, FR) | |
| ◦ | 6 Using intelligent tester or Techstream, cancel "DISABLE BRAKE CONTROL" | |
| - | 7 Connect the 2 brake accumulator pump connectors | |
| - | 8 Bleed the pump suction system (RR) | |
| ◦ | 9 Using intelligent tester or Techstream, perform "DISABLE BRAKE CONTROL" | |
| ◦ | 10 Bleed the rear brake system (RL, RR) | |
| ◦ | 11 Using intelligent tester or Techstream, cancel "DISABLE BRAKE CONTROL" | |
| - | 12 Using intelligent tester or Techstream, perform accumulator zero down | |
| ◦ | 13 Check and adjust the brake fluid level in the reservoir to the MAX level | |
| ◦ | 14 Clear the DTCs | |
| - | 15 Perform linear valve offset learning | |
| ◦ | 16 Check for DTC | |
| - | 17 Using intelligent tester or Techstream, check the accumulator pressure sensor output voltage |
NOTE:
- The listed order must be followed.
- After connecting the brake accumulator pump connectors, turn the power switch OFF.