hi everyone i am new to this site but i've had my fd3s rx7 for around 8 years. I have a problem with a knocking noise coming from the rear end and don't know if it's brakes or suspension i found one guy with the same problem but no answers on you tube.

//www.youtube.com/watch?v=AyH6zyTKLtY

can anyone help.

 

Hard to tell from that video, I didn't really hear a knocking noise. It sounded more like a drive train issue...prop shaft, axles or differential.
If it's 'knocking', probably the most common cause is worn pillow-ball bushings. They're spherical and there are six of them (3 each side) in the rear suspension. Just a little slop in one can magnify and translate into serious knocking noises. https://www.rx7club.com/suspension-w...-video-905032/
It can be difficult to pinpoint which one. Put the car up with the suspension in full droop and sometimes it's easier to feel by physically shaking the various arms. Personally I'd change all six if any one is noisey.