In my 95 M3 one rear shoulder belt tensioner stuck; it seems like the ratchet won't release. Since that's the side my daughter uses (Schroth belt on other side), I went to swap the two tensioners. Now the other side does the same thing!!! No obvious damage or problems, it just seems that both ratchets won't let go. I've tried it in all attitudes (i.e. angles relative to horizontal) and they're both just stuck. Any ideas? TIA