Hello everyone, I recently bought a 2008 Q7 and I knew the drivers side rear caliper was not compressing the pads onto the rotor. Turns out, of course, that the caliper is not receiving fluid. The passenger side rear and front calipers work well. I would like your suggestions on how to proceed, I have removed the caliper and confirmed that no fluid is flowing through the brake line at the wheel. Fluid level is fine.

On a side note, there have been a couple times that the brake pedal will hit the floor with no stopping power. This has only happened shortly after start-up when maneuvering at low speed.