the answer to the knocking from suspension!

[robbieraver]

Firstly im a specialist in suspension in Australia, we set up race cars for tarmac events and track specific applications.

Ive read so many posts about this topic, we have developed a 172 here for tramac/hillclimbs events and encounted the same problem.

The problem is the drive shaft is too long on the drivers side.

When a 172 is lowered certain angles change, in this case the inner cv joint is put under such aggresive angle it is binding up(the knocking you hear) when under load(cornering/turning) as the car is driven around a corner the inertia is transfered to the outside causing the car to roll, now this roll is causing the body of the car to move down while the suspension is moving up, these two effects are putting the drive shaft under very high angles, thus binding(knocking) will occur.

To make matters worse, when a clio is lowered with a atleast 2 degree's of negative camber this will make it bind up even more.

Thru testing we have discovered that both sides, drivers and passangers drive shafts will bind up.

The only quick fix to this, is reduce the amount of negative camber(this will reduce the drive shaft angle)


a permenent fix is to shorten the drive shafts.

 

[Šįk]

THANKYOU !!!

The missing piece to the jigsaw has been found.

My old 172 which I have just sold made this knocking noise and it's been lowered on coilovers with a full neg camber on front lol.. As soon as I sold it the buyer (my mate) has just had to buy a drivers side inner cv boot joint.. Which explains your answer 100% correct!

Looks like my Mate will be buying a few CV joints in the future! Haha.

Only if i new this earlier!

PSJ.

 

[Triki]

My 182 does it, and the ride height is standard.

 

[123stevevw]

what if 172 does it and it isn't lowered?!

Mine doesn't BTW but I've heard of a few that do

 

[.Ben.]

Could be just worn drive shafts or strut-top mounts on a standard car.

 

[robbieraver]

let me straighten this out...

the strut tops will add to this binding via not being bolted to the strut tower(chassis), the strut will move under load and add to the already loaded up drive shaft.

the drive shafts will only ever make a noise when you are at full lock and when they are very old and needing replacment, a sound at full lock will be fast knocking, very similar to the sound heard from many early clio's.

BUT im sorry to say i would need to hear most of the knocking to give you an answer as im not going to do that over the keyboard.

Many 172's here in Australia have the same problem with knocking when turning but not a single 182 has the problem, so if your 182 has a knock i cant answer what it could be other than what has been spoken about in various threads on noises.

If owners are going to shorten the drive shaft, DO NOT SHORTEN the original, as welding will weaken the shaft, and this is one area you want strenght.
The way to do it properly is most specilists in drivelines/drive shafts will have a blank shaft that you will be able to specify lenght size etc etc..

 

[ripp]

by how much the length should be increased? was thinking of elongating the mount holes of the lower ball joint by a few mm, to reposition the hub further to the exterior and creating space for the drive shaft instead of shortening it. does this sound right? this also will give a bit of camber which can be corrected via camber bolts if necessary

 

[jeffro]

orrrrr..... re-drill bottom ball joints by 5mm and exstend track rod ends!!!!! if u run a bit of camber it wil help get the ackerman angle more inline too by doin all this

 

[sideways danny]

it's entirely down to the top mount cup hitting the body. renaults fix is to dremel the hole where is hits. I've done a fair number like that and it works perfectly

 

[Fred@BTM]

i'm with danny on this one, nowt wrong with the driveshafts, its rare they fail mechanically (gaitors are a standard failure)

Renaults offical fix now is the one i highlighted aa few years ago with the washers

 

[ripp]

yeah but... I'm having solid mounts and the knock appears some times, and only when the car is cold (first drive off in the morning). so what's to blame now? drive shaft seems ok (the other one is new actually)
and it's not really a knock, I mean you barely could hear it, it's more like running over a small bump, you feel it rather than hearing it

 

[ripp]

any other opinions?