Rear pads and disks help....

[johnsbegood]

Hi guys, just a quick one, the pads and disks are shot on my tdi B5 so will need to replace.
2 things, when I rewind the caliper in do I need to clamp off the hose and open the bleed nipple to drain off excess fluid or can I just loosen the filler cap and push the piston back?
And when finished the disks and pads do I have to be careful when pumping the brakes? Read somewhere do not push the pedal too far??
Also anything else before attempting this job?
Cheers
Paul