I just rebuilt one the right rear brake caliper on my '92 Talon TSi AWD. First time I've ever done this, and it was as rusty and cruddy as one could imagine. Between taking them apart and then cleaning, derusting and painting them and the rear suspension members, anything connected to them and the wheel wells, it's been a really involved job, taking well over a month of half days several times a week. But now it's mostly done and I'm ready to finish rebuilding the calipers and put them back on the car.

The thing is, after putting the internals back together, largely following the superb how-to that Calan posted over 10 years ago (but with my own variation on how to compress the spindle assembly using a washer and small snap ring), when I tried to install and retract the piston using needle nose pliers, after the piston went all the way down and in, it kept on spinning, without moving axially, which seemed weird.

So I'm wondering, is there something wrong with one or more parts to make this happen, did I do something wrong, or is this what's supposed to happen? Did the piston threads pass the end of the spindle threads, which is why it's spinning without further retracting the piston? If so, should I spin the piston half a turn or so the other way so the threads make contact again? Or should I keep the piston as is and only make sure that the v-shaped depressions on the top align with the brake pad pin?

Update: I took a lot at the still disassembled left caliper just now. I screwed the spindle into the piston, and after the spindle screwed all the way in, it kept on turning with a little bit extra force, not using any tools, just whatever torque my fingers could apply. So it appears that it's supposed to be able to keep turning after completely retracting, to align the cutouts on the piston end with the pad pin, I assume. Can anyone verify this confirm that this is per design?