Quote:
|
Originally Posted by blueranger
when the piston is pushed against caliper the fluid is compressed. and when the piston is released there is a fluid bubble in the resivor. take the cover off your resivor and have some one push the brake and watch the motion of the liquid. however slight there is circulation. now just use your turkey baster and change your fluid. brake fluid is very cheap so who cares about waisting brake fluid. My car is 24 years old and the brake fluid has never been changed even with the turkey baister... I will change tomorrow with the turkey baister and report back to you the color change... right now it looks like mudd.
|
Brake fluid is designed to be almost completely incompressible. Any compressibility in the system would make the brakes spongy and could result in brake fade. This is what happens if you have air in the system, or if you have moisture in the fluid that can flash when heated in the caliper (due to not changing the fluid in 24 years). In reality, there is a very small amount of fluid movement from the reservoir into the brake lines when the brakes are pressed (how much does the reservoir level go down when the brakes are pressed?). When the brakes are released, this small amount returns to the reservoir. This is not circulation, this is a few CCs (at most) moving back and forth in the first few inches of the brake line. There is no driving force to get the vast majority of the fluid back to the reservoir.
Yes, changing the fluid in the reservoir will change the color of the fluid in the reservoir. However, it will do very little (or nothing) for the rest of the system.
Changing just the fluid in the reservoir is a complete waste of time.