rear brake piston wont screw in
 

what the hell, im trying to get the piston to screw in and it just keeps turning and turning and turning....do i need to take some fluid out of the resivour?

You need to push in the piston while turning.

Same as above Turn and push at the same time . Good skill to you .

Which way do you turn it? clock wise or counterclockwise?

usually counterclockwise......

IT IS MOST CERTAINLY CLOCKWISE!!

Un-cap the reservior as well.

If you're worried about the fluid in the reservoir, make sure the level is low enough that as you screw back in the piston, you don't overflow the brake fluid in the reservoir. It does make a mess when it overflows! If it's to full, just suck some fluid out. Also a good time to bleed your brakes/flush the fluid.
Just my 2c

I always just open up the bleed screw on the caliper. I hook a hose on the end of the bleeder & run it into a can.

As you turn the piston in (Clockwise) you can see the fluid displaced in the can.

The resistance is also much less with the bleed screw open. Plus depending on how far the piston is extended, you are backwashing contaminated fluid through the system.

The same holds true when retracting the pistons on the front calipers. With the bleed screw open the pistons retract much easier & no backwash.

Plus, with the bleed screw closed I've had one piston extend while I was retracting the other pistons. PIA

just finished a brake job tonight. It turns clockwise .

A shop manual would clear up a lot of confusion and lost time for you.

later

+1 but with SpeedBleeders.