The dust boot's lip doesn't want to seat in the groove with the piston in place and the piston doesn't want to slide into its hole with the dust boot already seated. I will post a link to what I am talking about shortly. The process I am stuck on is at the bottom of the page.

 

I remember that a while back doing one on another car.
IIRC I wound up using a plastic screwdriver or something like that to carefully wedge it in there. it was a PITA but I eventually got it done.

 

Last step of the link is giving me trouble. Using a mini-flathead screwdriver...not working so hot...

http://www.nicoclub.com/articles.php?id=214906

 

take your time, in the 300zx calipers when i rebuild them i put the rubber on the bottom first, but he says he used his finngers, to push it in so try that and try to rotate the cover while putting it in helps on everything i do.

 

Finally got it done and the calipers are back on the car...what a PITA!