Knocking noise from osf

[neil_f]

As per title there's a slight knocking noise from the front offside suspension . It only happens if driving on a cobbled street or similar surface. Doesn't make a noise during normal driving or over bigger bumps. It had all the front upper arms replaced by audi 10k miles ago so doubt it would be that. Could it be the drc on the way out? Had a quick look at the damper and can't see any obvious signs of leakage and car still handles fine. Dampers were all replaced 40k miles ago . Any thoughts greatly appreciated?

[rwilsonrs4]

could be anything , steering rack mounting bolts partially loose over time , multiple bushes and joints on the suspension,can have issues top mounts loose or strut inset locknut loose roll bar link roll bar bush Can something loose on anything, contacting with something else , will need a mechanic to do stress check on all parts to see if there is play on anything
As the DRC is diagonal split the knocking can be heard at the front but its the opposite corner that may have a leak as the pressure on that side thats the equalising valve which transmits the noise to the front , or it also can be heard from under the bootfloor depending on how much pressure lost but if DRC fails its knocking continually so unlikely to be that normal roads but look at LHR for any leaks

[rs user]

some mot garages have a shaking table-these can be good for finding suspension knocks that sometimes the pry bar method can miss

[cocovs6]

Could be many things causing the knocking as there are many components in suspension/steering which could be it. I had recent problem with knocking from suspension which turned out to be a pain in the a**e to find.

After fitting coilovers replaced top arms as well. After few days or so started getting knocking from suspension. Noise coming from top arms so got another set put on as thought they were faulty. Still the same.

Turned out to be problem with the hub carrier. Where the ball joint is pinch bolted into carrier some of the alloy metal inside the hole where ball joint locates had broke away when removing old top arms. This was causing the knock after few days as it wasn't getting as tight a grip as you would normally be. You should only tighten pinch bolts to required torque instead of rumping them up as you can crack the hub carrier.

Fix involved filling the hole with liquid metal and fitting new pinch bolts with two steps on them as fitted to newer Audi's. This cured the problem as other option was new hub carrier which would have been around £500.

The specialist I took it to has noticed more and more Audi's coming in with this same problem with some metal breaking away in hub carrier. Also more noticeable with coilovers if lowered as more load on suspension than standard DRC.

This might be worth looking at if struggling to find an obvious culprit.

[rs user]

Could be many things causing the knocking as there are many components in suspension/steering which could be it. I had recent problem with knocking from suspension which turned out to be a pain in the a**e to find.

After fitting coilovers replaced top arms as well. After few days or so started getting knocking from suspension. Noise coming from top arms so got another set put on as thought they were faulty. Still the same.

Turned out to be problem with the hub carrier. Where the ball joint is pinch bolted into carrier some of the alloy metal inside the hole where ball joint locates had broke away when removing old top arms. This was causing the knock after few days as it wasn't getting as tight a grip as you would normally be. You should only tighten pinch bolts to required torque instead of rumping them up as you can crack the hub carrier.

Fix involved filling the hole with liquid metal and fitting new pinch bolts with two steps on them as fitted to newer Audi's. This cured the problem as other option was new hub carrier which would have been around £500.

The specialist I took it to has noticed more and more Audi's coming in with this same problem with some metal breaking away in hub carrier. Also more noticeable with coilovers if lowered as more load on suspension than standard DRC.

This might be worth looking at if struggling to find an obvious culprit.

the uprights/carrier are generic right through the b6/7 range so it can be done/swapped out for a palatable price with another used item
the only part that differs in the front end upright set up is the hub itself for the rs4-its reinforced...
deffo use a torque wrench for the pinch bolts as you said

[cocovs6]

Could be many things causing the knocking as there are many components in suspension/steering which could be it. I had recent problem with knocking from suspension which turned out to be a pain in the a**e to find.

After fitting coilovers replaced top arms as well. After few days or so started getting knocking from suspension. Noise coming from top arms so got another set put on as thought they were faulty. Still the same.

Turned out to be problem with the hub carrier. Where the ball joint is pinch bolted into carrier some of the alloy metal inside the hole where ball joint locates had broke away when removing old top arms. This was causing the knock after few days as it wasn't getting as tight a grip as you would normally be. You should only tighten pinch bolts to required torque instead of rumping them up as you can crack the hub carrier.

Fix involved filling the hole with liquid metal and fitting new pinch bolts with two steps on them as fitted to newer Audi's. This cured the problem as other option was new hub carrier which would have been around £500.

The specialist I took it to has noticed more and more Audi's coming in with this same problem with some metal breaking away in hub carrier. Also more noticeable with coilovers if lowered as more load on suspension than standard DRC.

This might be worth looking at if struggling to find an obvious culprit.

the uprights/carrier are generic right through the b6/7 range so it can be done/swapped out for a palatable price with another used item
the only part that differs in the front end upright set up is the hub itself for the rs4-its reinforced...
deffo use a torque wrench for the pinch bolts as you said

Yes you can do it cheaper but if I was replacing carrier would be replacing with new carrier and bearings instead of used as used carrier may have same problem. That is were the approx. £500 came from.

[neil_f]

Thanks for the replies guys. Hoping to get a good look at it myself over the weekend (weather dependant ). Failing that there's an audi specialist near me who gets a good name so I'll try them.

[RS4JAY]

Tie rods?

[Covkiller]

Knocking is normally a simple fix, get it on a ramp and a big leaver, wiggle the normal stuff about like track rod ends, top arms etc and you will find it. When you find it change the other side too. Good luck. Keep us informed and photos.

[Tommcole]

Any update on this ? I have the same issue .. :/

[neil_f]

I've not had time to get a look at it yet partially due to the weather and the car has been getting used a lot. Hasn't got any worse at least !

[neil_f]

So finally got time to have a look at the suspension. Doesn't appear to be any leak from the damper so hopefully that's a good sign! Had a good poke about and the only part that I think has some play is the anti roll bar drop link. Going to replace these and see if it cures it as they are not expensive anyway. Checked all bolts were tight- no issues . Only thing I haven't really checked was what was mentioned previously about the ball joint into the hub carrier . Given it's done almost 12k miles since the top arms were replaced I'd have thought it would have started knocking well before now if that had been damaged when Audi replaced them?

[Covkiller]

Sounds logical. Keep us posted. Good luck.

[neil_f]

So finally got time (and no snow!) to fit the droplinks. Easy job to do and touch wood seems to have cured the knocking noise . Bought a pair ( thought it made sense just to do the other side as well) from euro car parts for £37. Took about an hour in total.

[Covkiller]

Well done and easy fixes are always the best