04-27-2008, 10:55 PM
Join Date: May 2006
Location: West Palm FL
My Ride: gets rid of hickups
Originally Posted by BrianLeveille
I'm one of those folks who likes to learn to DIY more and more things myself, but have always been hesitant to do brakes as it is a safety feature. Well, after reading up, especially this great DIY, I'm building confidence to do a brake/rotor replacement myself.
I have a question about compressing the piston: how does the piston, pad, and pedal all "know" how to adjust themselves after the brake job is done?? IOW, how does the pad position itself against the rotor with respect to the changing pedal pressure, especially considering that, in my mind, compressing the piston to get the caliper back on messes with that??
This is what happens:
+When you compress the piston you reset the pads completely
+The brake fluid in the master cylinder raises
+You reassemble the brakes (the pads are not touching the rotors)
+So before you drive the car you have to pump the brakes to set them to the rotor
+Now the pads are touching the rotors so when you hit the pedal you get immediate pressure (the fluid in the master cylinder goes back to normal level)
330xi VF Charged Widebody