Hello all, I would like to repost on this thread my findings on this horrible noise. I was almost subject to a large mechanics bill myself before trying this out.
I've had MK3.5 Octavia VRS for around a month now and have had this noise for almost my whole time owning the car. What started with mine was brake squeal, which prompted me to have the calipers off and pads out. There was no copper grease around the edge of the pads, after fitting some grease and refitting the squeak was gone but I had this horrible clonk when going over rough road, pot holes but not over speed bumps.
I had a mobile mechanics come out and take a look, all of the other suspension components, lower arms, anti roll bar bushes, drop links, struts and top mounts were fine. The mechanic told me my driveshafts were knackered and there was play up and down in them as well as an oil leak from the gearbox I had a look myself and found he was telling a lie. He took my money and ran because he didn't know what the issue was. Minea a 6 speed manual.
It was that evening that I was speaking with a friend who said if it isn't the above it could well be brake pads. So I went outside with a screw driver and lightly pried the pad up in the carrier DONK, pried it down DONK. There's your issue. There was around 5-6mm movement of each pad in the carrier.
Headed down to euro car parts the next day and bought a set of pagid pads. (175mm) Fitted them in myself and they are a snug fit. No movement up and down or back and forth. One happy man. The pads I removed were brembo. They didn't have any of the plates fitted to the rear of the pad, the pagid do and this stops the slack on the pad thus solving this issue. Very simple fix to a very annoying problem. I hope this helps you all. Don't buy brembo pads buy OEM (TRW) or Pagid. Have a good weekend 😁