Rear brake questions for 92 190E

[VettesRule]

Hi Gang,

I just replaced the front pads on my 190E. No problems!

I have some questions on the rear pad replacement.

1. How do you fill the rear axle portion of the master cylinder?
2. How do you pull the rear pads out? I pulled the caliper off the mounting bracket without problem but there seems to be two rods that have a threaded end but no aparent grip on the other end.
3. Do you need a special tool to retract the rear caliper pistons? Are the pistons threaded?

Thanks,