Z4-forum.com

Evening guys,

Got a couple of minor issues that I'd like to sort out, if for no other reason than my own sanity!

PDC issues - one regular beep followed by a long high pitched beep, then it switches to a regular normal pitch beeping. Checked sensors and all are clicking, although two are louder. No dirt on the sensor either and the speaker is connected fine.

Knocking - from the front axle somewhere! Happens when going over bumps up to around 25mph, after that its either not happening or not noticeable. Also happens when stationary and rocking the steering wheel, along with slight play in the wheel. The wheels feel as though they have a slight play when I try and wobble them with the car on the ground too, so this leads me to assume wishbone bushes? I was looking at a bit of a bush refresh on the front axle as a routine thing anyway, does this sound like the issue?

Wiring for the PDC?

Drop links? Lower arms? ARBs? Top mounts? Could be quite a few possibilities. Sure someone will post some troubleshooting tips.

Knocking sounds very much like suspension bushes to me! I had mostly the same symptoms (but also had large knocking sound when on full lock too). My local garage diagnosed it as bushes. A few hours later and a signficantly lighter wallet there were no more knocks

Which ones though, there are many!

I'm planning on changing the front control arms and related bushings anyway, and may well do the arb bushes and drop links while I'm at it. Shouldn't be much more after this to go wrong with the front end, I imagine?

I tightened up the strut bar nuts last night and this seems to have remedied some of the knocking, it was a lot less instusive on the drive to work this morning.

Don't just tighten them up, do them to spec from TIS which is torque plus angle.

Arms, ARBs and drop links should tighten everything up.

I'm finding a lot of conflicting information about how tight they should be, any input on that count? Trying to find specific information on TIS with a mobile browser is a lesson in futility!

Here it is: