pnoyslimm

I think you mean, "mounting bracket". what the brake calipers bolts up to? Where does it "wiggle" from, the bracket or caliper? No offense, but did you bleed your brakes? your pads could be spaced to far out? Only thing i can think of is, your mounting bracket bolts are loose, or your wiggling to hard.

if your brake booster on your 81 is an M90, i would go that route, use the 83 BB and BMC. i used an 82 BB on my 83. get everything you can if your not 100% Brake booster, brake master cylinder, both brake lines that come off the BMC, brake prop valve, 3way split, and the brake booster check valve.