TL;DR clicking noise after changing brakes pads and rotors in rear to find a new clicking noise on both sides in the rear. what do?

I helped my friend change shoes and pads in the rear on his 2006 4runner today and it went flawless except for one thing. as always, the rotors were tight because of the shoes for the emergency brake so I used the old 8Mx1.25 screws to pop them off and on the right side it popped one of the caps for the springs for the shoes. usually these are easy to put back on with a normal brake shoe system but these have the back plate with the wheel studs in the way so working around that, straining with 4 guys pudgy fingers we got it put back together. Changed the rest of the brake components, torqued everything to spec, pumped the brakes and went on our merry way but there was a clicking noise at both rear wheels at low speeds. Anyone know how to diagnose this? could it have been there before? They dont know so much about working on these and i only know the basics
Thanks