Noise under cat steering gone strange

Was It just one clunk or is it still happening when turning or going over bumps etc?

My money is on wheel balance out, along with a balljoint worn. If it is just that, it won't be mental

money but needs to be sorted ASAP as it will wear your front tyre/tyres fairly quick.

The balljoints on the A4 are not replaceable separately and are part of aluminium arms so can definitely add up quick

It depends on what's gone, there are 4 balljoints on each corner all requiring the whole arm to be replaced. If it's the banana arm for example I'd budget about 150 plus fitting per side but best get it properly diagnosed

You said noise gets louder the faster you go =Wheel bearing?

Noise can be heard from 20mph and the higher frequency when going faster and could be collapsing as when car is jacked up too much free play when wheel is grabbed at 6 and 12 and much movement

Out of curiosity what mileage is up on it.

i had a 2009 a4 with 450k km on it.

It never gave any trouble with balljoints in that time.

2 front wheel bearings replaced around the 420k mark.. just started making noise.

One other question.

Did you get tyres in the last few weeks or puncture fixed or breaks done

Are the wheel studs tight..?

Id be inclined to get the car checked asap tbh

The main bottom ballpoint that goes into end on straight arm is replaceable separately and in my case on A5 is the only one to wear out.

One of the many reasons i not buy a German car is the amount of money for repairs every few years , kept us in business for many years with repairs.