Ok, so I have a dumb question. I have a new piston and seals for the rear caliper on my 426. What I can't see in any photo's is the orientation of the piston. It has an open cavity on one end, and a smooth face on the other. My question is which way does it go into the caliper? I would think the open cavity faces away from the rotor so the fluid would fill it up and push the smooth face against the pads but I am unsure. Hopefully somebody knows..... Thanks.