I did up a huge thread on the Australian RS forums, but basically the symptoms are as follows:
- Occurs when braking, then again when taking off almost 100% of the time. It occurs in two's. So if it didn't happen under braking, then it doesn't happen under acceleration.
- Occurs over bumps occasionally
- Can be reproduced when turning the wheel when parked and stationary
- Steering does feel a bit off.
What I've checked:
- Top mounts - they are solid Pure Motorsport items. They are tightened very well. The knock is coming from lower anyway
- Wishbones and lower ball-joint. I've checked these are tight and no play. I've just replaced them anyway - they are brand new
- Track rod ends - these are tight. I'm not sure if they are free from play, but they do rotate about 1 degree about their length axis. I think that is normal judging from other cars I've worked on.
- Anti roll bar bushes. They are tight, and good condition. Can't see it being them.
- Engine and gearbox mounts. New VibraTechnics mounts put in 2000km ago
I'm really lost as to what it could be. Everything feels very tight about the suspension. I am beginning to think it could be the steering rack because of the fact it occurs when turning the wheel at stationary. But that doesn't explain the fact it occurs when taking off and when braking. So possibly a upper gearbox mount?