Your statement has no basis at all in facts.
Really? OP said he needed a breaker bar to remove the caliper bolts. That indicates they were grossly overtightened. If that’s not worrying quality, I don’t know what is.
Out.
JS
Sorry, I’ve not helped here . I’ve referred to the caliper bolts when in fact I meant the hub/carrier bolts
The caliper to carrier bolts were fine. As mentioned elsewhere, they aren’t massively tight, just hand tighten with a ratchet then a quarter turm
the carrier to hub bolts were the ones that (rightly) needed a breaker bar, as they take the braking strain.
sorry for confusion, all bedded in nicely now.
and I only added copperslip to the very front face of the piston when it contacts the pad. Not on the piston sides
.
An update, i didn’t get round to replacing the screws, so started to notice a “tick” when braking at low speed. This turned out to the the disc rotating a few mm on the hub and stopping on the wheel studs. Clearly needed sorting so finally located some screws on eBay and all fitted fine. So yes, they do serve a purpose and need replacing
I would review your install from the ground up.
The disc cant rotate as the wheels clamp it to the hub and if its a few millimetres of movement the stud hole size is wrong or you are measuring the movement at the circumference.
The locating screw positions the disc so the clearances around the stud are even when the wheel nuts are tightened. If its left off its not an issue for if the disc was ever to move it would move forward 0.5 millimetre or so the first time you braked and then rest on the studs until removed again. The locating screw is tiny in relation to the torque applied so its the wheel nut clamp action that stops it shearing ergo: the disc shouldn’t rotate. Most modern cars do not bother with the locating screw and rely upon fine disc to stud tolerances and wheel nut clamp forces.
It is at the circumference, I’d say 5mm or so . Clearly mazda fitted the set screws for a reason to alleviate that so I’m happy to refit .