If your vehicle is showing clicking noise from the wheels when braking in reverse, here are the most likely causes and the parts you'll need to fix each one.
Brake pads naturally shift slightly when the vehicle changes direction. If the anti-rattle clips or shims are worn, missing, or improperly installed during a recent brake job, the pads will make a sharp click against the caliper bracket when braking in reverse.
If the bolts securing the brake caliper or its bracket were not tightened to the correct torque specification, the entire assembly can shift and click under reverse braking loads.
A loose spindle nut allows the CV axle splines to shift slightly inside the wheel hub when the rotational force reverses, creating a metallic click or pop.
Suspension bushings absorb braking forces. When reversing, the braking force is applied in the opposite direction, causing a worn or torn bushing to shift suddenly and produce a clunk or click.
Although typically heard as a continuous clicking when turning, a worn CV joint can also produce a single click when the driveline is subjected to reverse torque combined with braking loads.