Quote:
Originally Posted by ggggbmw
What you are describing is a 'pressure bleed', using a pressure bleeder device. Typically a Motive or Schwaben pump. This process does NOT bleed the ABS unit, except for the minimal passages that go through the pump.
The ABS pump has a lot of valves and passages and the pump itself that hold some brake fluid in them. To flush the ABS pump and valves, and the associated passages in the pump block, you have to 'cycle' the pump. This runs the pump and cycles the valves open and closed so that as new brake fluid moves through the system it gets into every part of the ABS block.
This is a great video on using the BMW ISTA maintenance software to do the ABS cycle bleed:
The process with an OBD tool is usually the same. Just a different tool you are pushing the buttons on. My Schwaben/Foxwell tool even steals a lot of the text from the ISTA software, and the steps are identical.
FaRKLe0079 posts a lot of good videos. He also has a good simple pressure bleed video he links to in this one.
Do you have to do the ABS cycling? Maybe not every time. I only do it in the fall when I put LV fluid back in for the winter. But definitely if you got air in the system, or you at several years since the last time you did it. |
Thank you, great information. And yes I am thinking of doing the ABS cycling as I just bought my 2018 and suspect the brake fluid has never been serviced and that puts the fluid at 3 years old.