Hi I'm new here and thought I would start out by posting some details on ABS bleeding. I'm not a mechanic and happy to be corrected.
Recently I had to bleed my whole brake system and have listed below how I went about it and some other relevant info that may help you if you decide to do the same.
My 2006 147 GTA runs the Bosch 5.7 ABS system with 12 solenoid valves and four hydraulic brake circuits. The ABS system uses an electric pump to pressurise brake fluid to the circuits.
Each of the hydraulic circuits is controlled by a load valve, normally open, and a drain valve, normally closed. When the ECU detects one wheel decelerating at a rate much greater than the others, the ECU closes the load valve and opens the drain valve for that wheel to bleed off hydraulic pressure and prevent lockup. Once the imbalance is corrected and the wheel is decelerating at roughly the same rate as the others, pressure must be reapplied to the brake caliper to help stop the car. This is accomplished by closing the drain valve and opening the load valve.
Unless the ABS is activated between normal manual brake fluid bleeding the ABS system holds brake fluid. In my case the fluid I got out of the system was cloudy and had flakes in it (suggesting to me it was still the factory fluid). Of course you could find a good stretch of road and slam on the brakes to circulate the fluid or you can follow below...
I used Multiecuscan (MES) 3.6 on a HP Mini laptop running Windows 7 starter connected to the OBDII port via Lonetec brand MES Adaptor Lead Set and a ELM327 USB cable.
I don't know if bleeding the ABS circuit should be done regularly, but because I had air in the system I had to do it (definitely do it if you change a circuit pipe or master cylinder). I strongly suggest that if you have brake bleed issues, that you bleed the system normally before using MES to action the ABS valves.
1. Check fluid level
2. Bleed system normally. I do RR - LR - RF - LF. Your choice.
ABS bleeding (only after normal bleeding)
1. Constantly check the fluid level. The reservoir filter can trap the fluid and can give false readings - which is why I remove it.
2. Connect the tubes to the bleed nipples - I run four tubes (that go upwards first before going down in to the jars - (traps fluid which ensures no air can go back into the nipple) into 4 jars part filled with clean fluid. Although 1 jar moved to each wheel is enough. If you've got 330 6 pot brembos don't be a goose and forget about the second nipple...
3. Get MES ABS connected to "F6 Actuators" tab
4. Have some one ready to crack open the RR bleed nipple
5. Pump the brake pedal (approximately ten times) and hold with enough pressure to keep at equal to or above 15 bar (you can check the brake pedal pressure via ABS Parameters in MES) = basically hold pedal down enough to stop the wheels from spinning - do not put too much pressure on so that during the execute stage the pedal goes to the floor. Hold until #8 is complete
6. Tell your helper to crack the bleed valve and immediately (goto 7)
7. From MES (I connected to Bosch ABS 5.7 VDC on my 147 GTA) Execute the RR drain valve - the pedal will drop during the tick tick tick tick - then holds position, until - tick tick tick tick - and pedal drops again (don't let it hit the floor - if it does you are pushing too hard and must restart)
8. tell helper to close nipple
The helper should see some (cloudy) fluid and air come out - if not repeat the procedure but use the 'load valve' instead of 'drain valve'. Not sure if required but you could also possibly execute the pump motor (I did).
check reservoir
Check the pedal travel and if it is incorrect, restart the bleeding procedure.
do on remaining wheels
Right-hand rear wheel (1)
– left-hand rear wheel (2)
– left-hand front wheel (3)
– right-hand front wheel (4)
