INTRODUCTION
From experience resolving Lotus Turbo Esprit S4 brake problems, the following information is vital when bleeding the brakes. This information is provided courtesy of Lotus Cars Limited and may be found in the Service Notes (Lotus part number G082T0327J) Section JF. This is applicable to all Lotus Esprit models manufactured between 1991 and 2000 fitted with ABS brakes. Other important references in this manual include JF.4 - Brake Level Checks and types of fluids to be used, plus JF.11 – Brake Discs types and relevant critical dimensions. Additional information contained in the same manual includes diagnostic trouble shooting the Lotus Esprit ABS pressure switch (Lotus part number A082J6137S) and high pressure accumulator.
JF.8 – BRAKE BLEEDING PROCEDURE
If a Powermaster 11A booster/master cylinder assembly, or a pump/accumulator assembly has been replaced, or if air has entered (or is suspected in) the brake lines, the entire brake system including all hydraulic units must be bled at each wheel. If only a hydraulic part of the booster/master cylinder or pump/accumulator has been replaced, and air has not entered the brake lines, it may only be necessary to bleed at the booster/master cylinder bleed nipples.
Manual Bleeding
1. Ensure ignition is switched off.
2. De-pressurise the accumulator FIRMLY applying and releasing the brake pedal up to 40 times. A noticeable change in the brake pedal feel (to a hard pedal) will occur when the accumulator is completely discharged.
3. Clean the reservoir cover and top of the reservoir before squeezing the release tabs and lifting off the cover and diaphragm assembly
4. Fill or top up both front and rear compartments using only DOT 4 brake fluid from a sealed container until levels reach the full marks. IMPORTANT – use only DOT 4 brake fluid. Do not use DOT 5 silicone fluid or any fluid which has been exposed to the atmosphere for more than a brief period, or any fluid suspected of being wet, dirty or contaminated. Refit reservoir cover and diaphragm assembly.
5. If a replacement booster/master cylinder has been fitted, or if there is difficulty when trying t bleed the front master cylinder sections, ensure all air is removed from the master cylinder body by opening the brake pipe tube nuts on the master cylinder (front two only) approximately two turns, or until fluid begins to bleed Torque tighten the pipe nuts: - Front pipe (LHF brake) M13: 24 – 26 Nm (18 – 19 lbf.ft). Second pipe (RHF brake) M12. 22 -24 Nm (16 – 18 lbf.ft)
6. Bleed right front wheel brake:
- Attach bleeder hose to calliper nipple and submerge opposite end in clean brake fluid.
- Open bleed nipple.
- Slowly depress brake pedal.
- Close bleed nipple.
- Release brake pedal.
- Check fluid level and top up as necessary.
7. Repeat step 6 until the brake pedal feels firm at half travel and no air bubbles are observed in the bleeder hose.
8. Repeat steps 6 and 7 on the left hand front brake.
9. Turn the ignition on and allow the pump to run and pressurise the accumulator. NOTE: Turn off the ignition if the pump runs for longer than 60 seconds, and refer to “Pump Runs Continuously” (see later).
10. Bleed right hand rear calliper:
- Attach bleeder hose to calliper nipple and submerge opposite end in clean brake fluid.
- Open bleed nipple.
- With ignition on, lightly depress the brake pedal until fluid begins to flow from the hose. The harder the pedal is pressed, the more fluid will flow. Do not fully depress the pedal. Note that the pump will run during this process. Allow fluid to flow for about 15 seconds.
- Close bleed nipple, then release brake pedal.
- Repeat as necessary until no air bubbles are seen at the bleeder hose.
11. Check fluid level in the reservoir rear chamber. To avoid de-pressurising the accumulator at this interim stage, top up the reservoir rear chamber to a level 25mm below the full mark. IMPORTANT: Final fluid level must be checked after depressurising unit at step 14.
12. Repeat steps 10 and 11 for the left hand rear calliper.
13. Bleed master cylinder isolation valves:
- Attach a bleeder hose to the bleed nipple on the inboard side of the master cylinder, and submerge opposite end in clean brake fluid.
- With ignition on, apply light force to the brake pedal and slowly open the bleeder valve to allow brake fluid to flow until no air is seen in the fluid.
- Close the bleed nipple when fluid begins to flow without air bubbles
- Repeat procedure on the outboard side nipple (or use the “Tech 1” bleeding sequence)
14. Bleed accumulator:
- Turn off ignition, de-pressurise the accumulator by FIRMLY applying and releasing the brake pedal up to 40 times. A noticeable change in brake pedal feel (to a hard pedal) will occur when the accumulator is completely discharged.
- Wait two minutes for air to clear from the brake fluid in the reservoir.
- Remove the reservoir cover and check the level in both front and rear sections of the reservoir. If necessary, top up to the correct level – see start of this section. Refit reservoir cover.
- Turn on the ignition and allow the pump motor to run. NOTE: Turn off the ignition if the pump motor runs for more than 60 seconds. Refer to “Pump Motor Runs Continuously” in this section.
15. Bleed booster section of the booster/master cylinder assembly:
- Depress the brake pedal with moderate pressure and turn on the ignition without starting the engine for 3 seconds.
- Repeat this off/on procedure 10 times to cycle the solenoids. - (part of “Tech 1” bleed sequence)
16. Assess brake pedal “feel”:
- Apply brake pedal and note pedal feel and travel.
- If pedal feels firm and smooth without excessive travel, system is properly bled.
- If pedal feels soft or spongy or travel is excessive, refer to “Excessive Pedal Travel” in this section.
- If a “bump” is noted upon initial pedal application, or application does not feel smooth and uniform, refer to “Non-uniform Pedal Feel” in this section.
17. Road test vehicle and note pedal travel and feel. If any symptoms described above in step 16 appear, refer to the appropriate section below.
Excessive pedal travel
Excessive brake pedal travel exists if, when driving the vehicle, braking action does not start until the first 35mm (1.4”) of pedal travel. If after carrying out the brake bleeding procedure above, excessive travel is evident, proceed as follows:
1. Re-bleed front brakes (rear circuit maybe omitted) as described above in steps 6, 7 & 8 of ‘Manual Bleeding’, and check brake fluids.
2. Re-access pedal feel as in step 16 of ‘Manual Bleeding’ above. If excessive travel is still evident, first check fluid level, and then check for leakage throughout the brake system.
Non-Uniform Pedal Feel
Bleed the system using the ‘Tech 1’ bleeding procedure
Pump Runs Continuously
IMPORTANT: This procedure is to be used if the pump runs more than 60 seconds
1. With the ignition off, depressurise the accumulator by FIRMLY applying and releasing the brake pedal up to 40 times. A noticeable change in the pedal feel (to a hard pedal) will occur when the accumulator is completely discharged.
NOTE: In the following steps, use a suitable container and/or shop towels to catch the brake fluid and prevent it from contacting any painted surfaces.
2. Loosen but do not release the two tube nuts from the master cylinder front chamber (for the left and right hand front brakes)
3. Press the pedal to its fullest. Fluid should run slowly from around the tube nuts.
4. With the pedal depressed, tighten both the tube nuts.
5. Quickly release the pedal and re-apply using a jabbing (sharp and rapid) motion with full force.
6. Turn on the ignition and allow the motor to pressurise the accumulator.
7. Assess brake pedal feel and road test as in steps 16 & 17 of ‘Manual Bleeding’
IMPORTANT: If the pump still runs continuously, refer to ‘Hydraulic Diagnosis’
From experience resolving Lotus Turbo Esprit S4 brake problems, the following information is vital when bleeding the brakes. This information is provided courtesy of Lotus Cars Limited and may be found in the Service Notes (Lotus part number G082T0327J) Section JF. This is applicable to all Lotus Esprit models manufactured between 1991 and 2000 fitted with ABS brakes. Other important references in this manual include JF.4 - Brake Level Checks and types of fluids to be used, plus JF.11 – Brake Discs types and relevant critical dimensions. Additional information contained in the same manual includes diagnostic trouble shooting the Lotus Esprit ABS pressure switch (Lotus part number A082J6137S) and high pressure accumulator.
JF.8 – BRAKE BLEEDING PROCEDURE
If a Powermaster 11A booster/master cylinder assembly, or a pump/accumulator assembly has been replaced, or if air has entered (or is suspected in) the brake lines, the entire brake system including all hydraulic units must be bled at each wheel. If only a hydraulic part of the booster/master cylinder or pump/accumulator has been replaced, and air has not entered the brake lines, it may only be necessary to bleed at the booster/master cylinder bleed nipples.
Manual Bleeding
1. Ensure ignition is switched off.
2. De-pressurise the accumulator FIRMLY applying and releasing the brake pedal up to 40 times. A noticeable change in the brake pedal feel (to a hard pedal) will occur when the accumulator is completely discharged.
3. Clean the reservoir cover and top of the reservoir before squeezing the release tabs and lifting off the cover and diaphragm assembly
4. Fill or top up both front and rear compartments using only DOT 4 brake fluid from a sealed container until levels reach the full marks. IMPORTANT – use only DOT 4 brake fluid. Do not use DOT 5 silicone fluid or any fluid which has been exposed to the atmosphere for more than a brief period, or any fluid suspected of being wet, dirty or contaminated. Refit reservoir cover and diaphragm assembly.
5. If a replacement booster/master cylinder has been fitted, or if there is difficulty when trying t bleed the front master cylinder sections, ensure all air is removed from the master cylinder body by opening the brake pipe tube nuts on the master cylinder (front two only) approximately two turns, or until fluid begins to bleed Torque tighten the pipe nuts: - Front pipe (LHF brake) M13: 24 – 26 Nm (18 – 19 lbf.ft). Second pipe (RHF brake) M12. 22 -24 Nm (16 – 18 lbf.ft)
6. Bleed right front wheel brake:
- Attach bleeder hose to calliper nipple and submerge opposite end in clean brake fluid.
- Open bleed nipple.
- Slowly depress brake pedal.
- Close bleed nipple.
- Release brake pedal.
- Check fluid level and top up as necessary.
7. Repeat step 6 until the brake pedal feels firm at half travel and no air bubbles are observed in the bleeder hose.
8. Repeat steps 6 and 7 on the left hand front brake.
9. Turn the ignition on and allow the pump to run and pressurise the accumulator. NOTE: Turn off the ignition if the pump runs for longer than 60 seconds, and refer to “Pump Runs Continuously” (see later).
10. Bleed right hand rear calliper:
- Attach bleeder hose to calliper nipple and submerge opposite end in clean brake fluid.
- Open bleed nipple.
- With ignition on, lightly depress the brake pedal until fluid begins to flow from the hose. The harder the pedal is pressed, the more fluid will flow. Do not fully depress the pedal. Note that the pump will run during this process. Allow fluid to flow for about 15 seconds.
- Close bleed nipple, then release brake pedal.
- Repeat as necessary until no air bubbles are seen at the bleeder hose.
11. Check fluid level in the reservoir rear chamber. To avoid de-pressurising the accumulator at this interim stage, top up the reservoir rear chamber to a level 25mm below the full mark. IMPORTANT: Final fluid level must be checked after depressurising unit at step 14.
12. Repeat steps 10 and 11 for the left hand rear calliper.
13. Bleed master cylinder isolation valves:
- Attach a bleeder hose to the bleed nipple on the inboard side of the master cylinder, and submerge opposite end in clean brake fluid.
- With ignition on, apply light force to the brake pedal and slowly open the bleeder valve to allow brake fluid to flow until no air is seen in the fluid.
- Close the bleed nipple when fluid begins to flow without air bubbles
- Repeat procedure on the outboard side nipple (or use the “Tech 1” bleeding sequence)
14. Bleed accumulator:
- Turn off ignition, de-pressurise the accumulator by FIRMLY applying and releasing the brake pedal up to 40 times. A noticeable change in brake pedal feel (to a hard pedal) will occur when the accumulator is completely discharged.
- Wait two minutes for air to clear from the brake fluid in the reservoir.
- Remove the reservoir cover and check the level in both front and rear sections of the reservoir. If necessary, top up to the correct level – see start of this section. Refit reservoir cover.
- Turn on the ignition and allow the pump motor to run. NOTE: Turn off the ignition if the pump motor runs for more than 60 seconds. Refer to “Pump Motor Runs Continuously” in this section.
15. Bleed booster section of the booster/master cylinder assembly:
- Depress the brake pedal with moderate pressure and turn on the ignition without starting the engine for 3 seconds.
- Repeat this off/on procedure 10 times to cycle the solenoids. - (part of “Tech 1” bleed sequence)
16. Assess brake pedal “feel”:
- Apply brake pedal and note pedal feel and travel.
- If pedal feels firm and smooth without excessive travel, system is properly bled.
- If pedal feels soft or spongy or travel is excessive, refer to “Excessive Pedal Travel” in this section.
- If a “bump” is noted upon initial pedal application, or application does not feel smooth and uniform, refer to “Non-uniform Pedal Feel” in this section.
17. Road test vehicle and note pedal travel and feel. If any symptoms described above in step 16 appear, refer to the appropriate section below.
Excessive pedal travel
Excessive brake pedal travel exists if, when driving the vehicle, braking action does not start until the first 35mm (1.4”) of pedal travel. If after carrying out the brake bleeding procedure above, excessive travel is evident, proceed as follows:
1. Re-bleed front brakes (rear circuit maybe omitted) as described above in steps 6, 7 & 8 of ‘Manual Bleeding’, and check brake fluids.
2. Re-access pedal feel as in step 16 of ‘Manual Bleeding’ above. If excessive travel is still evident, first check fluid level, and then check for leakage throughout the brake system.
Non-Uniform Pedal Feel
Bleed the system using the ‘Tech 1’ bleeding procedure
Pump Runs Continuously
IMPORTANT: This procedure is to be used if the pump runs more than 60 seconds
1. With the ignition off, depressurise the accumulator by FIRMLY applying and releasing the brake pedal up to 40 times. A noticeable change in the pedal feel (to a hard pedal) will occur when the accumulator is completely discharged.
NOTE: In the following steps, use a suitable container and/or shop towels to catch the brake fluid and prevent it from contacting any painted surfaces.
2. Loosen but do not release the two tube nuts from the master cylinder front chamber (for the left and right hand front brakes)
3. Press the pedal to its fullest. Fluid should run slowly from around the tube nuts.
4. With the pedal depressed, tighten both the tube nuts.
5. Quickly release the pedal and re-apply using a jabbing (sharp and rapid) motion with full force.
6. Turn on the ignition and allow the motor to pressurise the accumulator.
7. Assess brake pedal feel and road test as in steps 16 & 17 of ‘Manual Bleeding’
IMPORTANT: If the pump still runs continuously, refer to ‘Hydraulic Diagnosis’