GR Yaris Single clunk felt in steering after car has sat a while

[Anphony]

I have had this issue with my GR for at least over a year, but I have not been able to pin point why it is doing it. The issue as best as I can describe it:

After the car has sat for a while (1 hour +), when turning the steering wheel left or right for the first time, a single clunk is heard and felt from the steering wheel / column. This only happens once, and then it cannot be reproduced until the car has sat again. Even when rolling down an incline, it will only clunk as soon as I turn the wheel once, not when I start moving. After the initial clunk, there are zero issues with driving / steering.

During this time, I have done the following which made no difference: Added camber bolts, alignment, Giro Discs, tightened steering rack to subframe, tightened subframe bolt, checked for play in tie rods. Previously (I don't recall when this started), I have also changed all engine mounts, tightened the bolts under the wiper cowl, and the car has stock struts with lowering strings.

Anyone have any ideas, or get a similar thing with their GR?

 

[Bronson]

Top mounts? Do you have aftermarket ones fitted?

 

[Istiban]

Probably not the same issue but some people reported clunks at full lock which turned out to be a loose bolt https://www.gr-yaris.co.uk/threads/suspension-clunk.8095/page-3#post-185367 post #56 in this thread but a general search for clunk will yield some idea's things to check.

 

[Onehp]

Is the car rolling already? If not and just dry steering, I would think about brake pads sticking to the disk or shifting in the caliper.

 

[Anphony]

Just to answer a few replies. It will occur if moving or not, but I am usually stationary when first starting. Also happens if the brakes are applied or not. I'm using the stock top mounts, but considering a getting a new set at least to have spares.

The amount of steering input needed to produce the clunk is minimal. If I accidently touch the steering wheel with my leg getting into the car, the clunk has already happened and I don't notice it.

 

[Anphony]

I'm going to just replace the strut top mount bearings to rule it out and they are cheap. Can they be replaced keeping the strut attached to the hub with just the top mount unbolted? Or does the strut have to come fully out to replace them?

 

[TheoRettisch]

I'm going to just replace the strut top mount bearings to rule it out and they are cheap. Can they be replaced keeping the strut attached to the hub with just the top mount unbolted? Or does the strut have to come fully out to replace them?

Where you able to fix the issue by replacing the bearings? Mine is doing the same since some time. Didn't thought this to be an issue but it seems with time it is getting more pronounced.

 

[halfbee]

Mine does it, I put it down to the EPAS motor energising and tugging at the column very slightly.

 

[Anphony]

I didn't replace the top mount bearing yet. I have the new ones, but still not convinced this would fix the issue. I drove the car to the Nürburgring at the weekend and did around 9 laps with no difference to the initial steering knock, for better or worse.

I am wondering if this is one of those things the car does as Halfbee mentioned with the power steering motor energizing or similar. Just feel better mine isn't the only one.