Braking Noise after brake service

I have a Ford Explorer; I took it to wheelworks and they recommended brake service , replacing the rear brake Pad and machine the rotor. After the service, there’s a knocking noise from the rear brake. The noise is not there (or not so noticeable) when braking softly, but very Noticeable when more the brake is pressed harder. What could be the cause?



Thanks

I would take the vehicle back where you had the brake worked on and give them a chance to fix it. Continued driving may damage the brake components, especially if something is loose.

You MAY have to take the tech with you for a test drive and apply the brake firmly to replicate the noise so he/she hears it.

Thanks. Actually, I took it back already. They blamed it on the inside drum of the rotor, the area that covers the Emergency brake. They said some built up or rust inside that causes the Noise. After they serviced it again, the Noise might have reduced (or gone) for a day, then came back. The same periodic knocking noise when braking (harder). Since they worked on the Rotor (machined) and replaced the PAD, I have a feeling that the rotor was not machined evenly (maybe warped or something?). Could a badly serviced rotor cause some knocking noise when brake is pressed?

you mentioned taking it back. did they actually take off the tire, and the drum to inspect it? or was this a miracle diagnosis from the service desk?

i would suspect the brake caliper bracket may be loose. but if it is not disassembled no one would know for sure.