Robert,
It's a method that is hardly ever used in the field because it is difficult to get a perfect enough vacuum to make it work - there will always be a little air left in the system. But at the OEM factories, it is worth the extra money to buy a really good vacuum pump. You can be sure that no one at the factory is under the car letting brake fluid out of the bleeder screws. They go to great lengths to make sure that no fluid gets spilled. It's a method that can work on our planes - fill the reservoir with fluid (not quite full) and pull as much vacuum as possible, hold for a while and then release. Might take a few times to get the air pulled out of the system. I'll admit I haven't done it - maybe I should as I've got one brake that is a little bit mushy. Of course,
this method relies on the idea that there are no leaks in the system that could let in air.
Gary
I have never heard of pulling a pure vacuum on the master cylinder and releasing fluid that will fill all wheel cylinders
properly. See all the methods listed on wikipedia.
Robert
I have never heard of pulling a pure vacuum on the master cylinder and releasing fluid that will fill all wheel cylinders
properly. See all the methods listed on wikipedia.
Robert