Bleeding Brakes - Vehicles With ABS and ABS/TC
Bleeding brakes - vehicles with ABS and ABS/TCImportant notes
Use only new DOT 4 brake fluid. Observe brake fluid quality.
The brake fluid change interval is 2 years in conjunction with Super DOT 4 brake fluid. This brake fluid is available under the following part numbers:
Container quantity 1 liter = 000.043.203.66
Container quantity 30 liters = 000.043.203.67
Procedure for bleeding
- Fill reservoir to its top edge with new brake fluid. Connect a bleeding device to the brake fluid reservoir. Switch on the bleeding device. Bleeding pressure is approximately 1.5 bar.
- Continue bleeding at the brake calipers. Do so in the following sequence: rear right/rear left/front right/front left. Open each bleeder valve until clear, bubble-free brake fluid emerges. It must be noted that bleeding takes place at both bleeder valves on each caliper. Bleed the outer bleeder valve first.
- Use a collecting bottle to make an accurate check on the escaping brake fluid for cleanliness, lack of air bubbles and to determine the brake fluid used.
- After installing a new brake master cylinder and/or a new hydraulic unit, do the following while bleeding: Open the right rear bleeder valves, then fully depress the brake pedal several times. Hold for 2 - 3 seconds after each depression, then release slowly. Repeat this procedure in the following sequence: rear left/front right/front left. This will remove all air bubbles (from the primary circuit).
Note!
^ Also carry out this procedure if the brake hydraulics were largely empty or if, after bleeding, residual air can be detected by excessive brake-pedal travel. Please Note! In vehicles with high mileage or in old vehicles, double the pumping cycles and use only half the brake master cylinder stroke (damage to the brake master cylinder/primary boots could occur).
- Switch off and disconnect the bleeding device. Correct the brake fluid level if necessary.
Note!
^ On vehicles with Traction Control (TC) consisting of ASR and ABD (4-channel system), the ABD circuit (in the hydraulic control unit) must be additionally bled when the hydraulic control unit is replaced or removed (see following text).
Bleeding the ABD circuit (secondary circuit) on vehicles with Traction Control (TC)
- Preliminary work: Bleed brakes as usual.
- To bleed the ABD circuit, the bleeding device remains connected (switched on). Bleeding pressure is approximately 1.5 to 2.0 bar.
- Connect the Porsche System Tester 2 to the diagnostic socket. The diagnostic socket is located in the driver's footwell (left-hand drive vehicles) or passenger's footwell (right-hand drive vehicles) near the fuse box. Switch on ignition. In the ABS/TC system, select the "Bleed" menu.
- Open the rear right bleeder valve (use collecting bottle).
- Press the Start button on the System Tester. This initiates certain functions in the hydraulic control unit (return pump, switch-off and switch-over valves are actuated). Bleed until clear, bubble-free brake fluid emerges. In addition (throughout bleeding operation) fully depress (pump) brake pedal as far as the stop at least ten times. Please Note! Double the number of pumping cycles for vehicles with extremely high mileage or for very old vehicles, and use only half of the master brake cylinder stroke (damage could be caused to the master brake cylinder/primary boots).
- Close the right rear bleeder valve. Then immediately press Stop button on the System Tester.
- Switch ignition off and disconnect System Tester.
- Switch off and disconnect the bleeding device. Correct the brake fluid level if necessary.