07-24-2019, 07:12 AM
If you look at the rear brake line routing you notice that the line has a high point at the master cylinder, to bleed this line and remove air in this line the new brake fluid has to be flushed quickly so that no air can remain in the high part of this line.
Or the caliper has to be removed and held up high in such a way so all the air in the line can slowly rise to the caliper and bled in the traditional way.
No such issues exist in the ( non abs ) front brake system, it lets air escape over time because the master cylinder is at the highest point and the ports in the master cylinder are designed so any air in the line can surface at the reservoir.
To me it is possible that disks can develop rust spots if left wet after a ride, this may influence the surface friction at that spot, the rotor is still true but can feel uneven when braking, this may take quite some time to reduce in intensity.
This happened to me and the intensity changed ( reduced ) when the front brake pads were replaced.
To see if the rotor is warped or the wheel mounting is not true the rotor could be measured and marked if a high spot is found and rotated 90 degrees and measured again, if the high spot moved with the rotation the disk needs attention, if the spot remains in the same place it may be the wheel is somehow affecting the runout.
Or the caliper has to be removed and held up high in such a way so all the air in the line can slowly rise to the caliper and bled in the traditional way.
No such issues exist in the ( non abs ) front brake system, it lets air escape over time because the master cylinder is at the highest point and the ports in the master cylinder are designed so any air in the line can surface at the reservoir.
To me it is possible that disks can develop rust spots if left wet after a ride, this may influence the surface friction at that spot, the rotor is still true but can feel uneven when braking, this may take quite some time to reduce in intensity.
This happened to me and the intensity changed ( reduced ) when the front brake pads were replaced.
To see if the rotor is warped or the wheel mounting is not true the rotor could be measured and marked if a high spot is found and rotated 90 degrees and measured again, if the high spot moved with the rotation the disk needs attention, if the spot remains in the same place it may be the wheel is somehow affecting the runout.