Um, yeah...

In any case, the Z-series calipers weren't particularly robust even for back then. The "cheap sidepull" of choice was Dia-Compe.

Here's a couple pictures of your beastie, but none that show the arm arrangement:
http://www.velobase.com/ViewSingleCo...m=117&AbsPos=5

IIRC, there should be a plastic washer in between the two caliper arms. Is it there?

If you really get stuck, I may have a spare Z-series caliper in my bin o' parts. I could send it to you if it's the same reach.

(Old bike mechanics never die. They just disappear under their piles of parts.)