Hi All,

I really hope you can help me with this. I drive an MY2005 STi with the following suspension upgrades:

Whiteline front 22mm ARB
Whiteline rear 24mm ARB
Whiteline Anti-lift Kit
BC Racing coilovers

I did a track day yesterday. All was going well until the late afternoon when I developed a sudden vibration and knocking sound from the front nearside of the car. It initially sounded like a chunk of the tyre had torn away and was banging against the wheel arch liner. I drove very slowly back to the paddock, during which time the vibration disappeared to be replaced by a knocking sound. On inspection, the tyre was fine but I replaced the wheel anyway just to be sure. Problem still present.

I initially thought that perhaps the front nearside coilover had worked loose. My coilovers were only fitted 3 weeks ago and I figured that perhaps one of bolts had loosened under the stress of a track day. Nope - the three nuts holding the topmount in place were all still tight, and so were the two large bolts holding the strut to the hub. None of the other nuts I could see under the car were loose.

The ARB and drop link seem to be fine. The ARB bushes are still in place.

I limped home and found that the car still runs fine. No vibrations through the wheel, no tramlining, no pulling to one side under braking etc. The only difference is a very loud knocking every time the front nearside wheel goes over a bump in the road. It sounds like something is loose but I seem to have eliminated most of the possible causes. The noise seems to be coming from the topmount area. I checked under the bonnet but can't find any loose components in that area.

I'm really scratching my head with this one. The only 'incident' on the day came after I overtook a Caterham (I was surprised too!) and carried too much speed into the next chicane, running over a cone. However, I'm not yet convinced this explains it - the cone was very lightweight and passed beneath the car without leaving so much as a scratch. Also, the knocking started about 30 minutes or so after I demolished the cone.

Sorry to leave such a long, rambling query but I'd be really grateful for your wisdom. This is my everyday car and I want to fix this asap.


Rob

 

have a look at the spring to check it hasnt snapped

 

Rose jointed/spherical bearings by any chance, just check the nut on the top-mount is still tight....

And drip a little engine oil onto it as well.

HTH

dunx

P.S. Check the spring platform lock rings are still locked too.

 

Thanks guys,

I had a good look at the spring and I'm sure it hasn't snapped. The ride doesn't seem to have changed at all.

Dunx,

I believe that I have pillowball topmounts at the front, are these rose jointed/spherical as you say? Also, where precisely should I drip some oil and what will this show me?

To tighten the spring platform locks I presume that I need to use the C-spanner supplied by BC. I haven't been shown how to do this and the instructions that came with the coilovers are absolutely appalling. Any tips so that I can be sure I know what I'm doing?


Rob

 

oil is just to help keep them lubed...

Spring platforms simply fit spanners and apply force to check they are locked together, will be obvious if they are loose. Spherical bearings are really a motorsport item IMHO so they are likely to be noisy on a road car...

dunx

 

Dunx,

Had a chance this evening to take another look. Turns out the nut on the top mount was slightly loose. I tightened it and the knocking has now disappeared! Only God knows how I missed this before but I'm pleased to have it sorted.

The car is now lovely and quiet again. Well, as quiet as an STI on coilovers is ever gonna be!

Ta,


Rob