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Knocking under hard braking \ Stationary steering



I've fitted Powerflex bushes to the wishbones and inner+outer ARB at the same time,
Went for a test drive and found the car knocks when braking very hard, sounds very similar to the noise you get from accelerating with worn engine mounts when the manifold hits the ARB.
After I finish braking and as soon as I start accelerating, it knocks again, as if something moves out and back into place.
It also knocks when steering more than half a turn while stationary, since it started to knock under hard braking.
I removed the front ARB from the car, and found out the knock was almost certainly gone. Put it back in, and the knock returned.
-All engine\gearbox mounts are tight, vibra+powerflex mounts, no excessive engine or gear stick movement.
-All nuts and bolts for the Top mounts, ARB bushes clips, wishbones, subframe, balljoints, calipers and carriers, front shocks
-Springs are sitted correctly
Seems related to the Powerflex ARB bushes, but they were fitted correctly, inner ones with the groove at the bottom, outers with the square housed inside the wishbones.
Any ideas?
 
Just noticed it was posted on the wrong section sorry,
Anyway here's a video, you can hear the knocking by the end of the braking, right after I relieve the braking pressure and the ABS goes quiet. You can hear it again when I just start accelerating. 0:04 , 0:09 , 0:18 , 0:20

 
Oh its a 172 ph2.
The powerflex are far from being well designed as far as the fitment goes, especially the inner ARB ones!
But those were the right size for my car, 23 outers 25 inners.
I might be buying new standard bushes if no other ideas arise, but haven't found anyone with the same problem with the bushes on the forum.
 
  PH2 172
Oh its a 172 ph2.
The powerflex are far from being well designed as far as the fitment goes, especially the inner ARB ones!
But those were the right size for my car, 23 outers 25 inners.
I might be buying new standard bushes if no other ideas arise, but haven't found anyone with the same problem with the bushes on the forum.

Agree the inners are a pig to fit, but those are the correct size 23/25 as long as you have the original 8200104120 ARB.
I have the same set up & it`s silent.
Was this a pre existing problem that the work you have done has failed to cure?
 
Nope, it started right after putting the powerflex arb and wishbone bushes.
Also changed spring and shocks about a week beforehand, but the problem wasnt there until changing the bushes.
 
  PH2 172
Nope, it started right after putting the powerflex arb and wishbone bushes.
Also changed spring and shocks about a week beforehand, but the problem wasnt there until changing the bushes.

Perhaps if you could post some pics, someone might spot something.
Did you notice that the mounting holes on the subframe for the wishbone have a larger diameter at the back, & the bolts should be fitted pointing to the front of the car, with the shoulder at the rear?
Also you have used the original bolts with the shoulder?
 
Can you explain what you mean by shoulders?
Origibal bolts were reused indeed, fittes with the nut at the correct side,
And yes 1 wishbone bolt hole is bigger than the others on booh sides, it is round and definitely wasn't created by a loose bolt.
 
  PH2 172
Yep they were installed correctly.
I've asked my alignment guy to take a look today, and he couldn't find anything loose/wrong either.
So I guess I'll order standard ARB bushes and try them, as I'm almost certain the noise was gone after removing the arb.
Although after reinstalling the ARB, it took some time for the noise to come back.
So any other thoughts are very welcome!
 

Mr R.

ClioSport Club Member
  A special one.
Yep they were installed correctly.
I've asked my alignment guy to take a look today, and he couldn't find anything loose/wrong either.
So I guess I'll order standard ARB bushes and try them, as I'm almost certain the noise was gone after removing the arb.
Although after reinstalling the ARB, it took some time for the noise to come back.
So any other thoughts are very welcome!
Do you still have standard engine mounts?
 
  PH2 172
@M90SR had a rack that knocked internally when turned from left to right & back, though there was no movement in the bushes, inner tie rods or track rod ends.
You could feel it if you put your hand on the centre of the rack, but only when it was on the floor, not on stands.
Changed the rack & it was gone.

What top mounts have you got?
Originals or the revised with the 27mm spacer nut.
MODIFIED 8200867250 27mm nut spacer.png
 
The revised ones with the new nut.
My steering rack does indeed knock while steering side to side while stationary, but it was always like that in the past years and it hasn't gotten worse by any means.
Engine and gearbox mounts are 100% not the problem
 

MrBlonde

ClioSport Club Member
My rack also has a small knock,but only if you do it a bit aggressively,i have a couple of new rack bolts to fit so hopefully that will sort it out.Both wishbone are new along with ball joints,also new the rods,all the bolts are tight.
So can either be back bolts or track rod ends which are about 3 years old.
 
Ok a few days later and I'm also getting endless squeaking and creaking as the car moves.
Doesn't matter if I'm steering, braking, accelerating, the noise is there as long as the car is moving.
Weird as I greased all the powerflex arb and wishbone bushes generously!
Any ideas before taking off the arb again to check if the noise stopped?
 

Louis

I Park Like a C**t
ClioSport Club Member
Still looking for a solution for the knocking lol
It got worse and worse over time, happens all the time when driving normally even
Check the 2 bolts for the lower balljoint. I had exactly these same symptoms and they just weren't tight on the NSF.

I also went over everything else nipping it all up. Check the nuts coming down from the stabiliser bar too down to the wishbone bushes.
 
Checked those a few times already, along with all the other nuts and bolts I could have thought of... Also calipers are new and greased. Thanks
It started right after changing arb bushes and wishbone bushes to powerflex,
I lowered the subframe without fully removing any of the 4 bolts. Could have I dont something wrong when torquing back the subframe?
 

Rystar

ClioSport Club Member
  2003 Clio 172
I've also recently changed the subframe on mine, and renewed ALL the bushes with poweflex black, and i have the same knocking i think, Acceleration, braking, steering stationary. Also feels like something is almost sticky when pulling away? Not sure if we've got the same symptoms...
 
  PH2 172
Checked those a few times already, along with all the other nuts and bolts I could have thought of... Also calipers are new and greased. Thanks
It started right after changing arb bushes and wishbone bushes to powerflex,

Have you changed the ball joints recently?
I`m thinking along the lines of have you been supplied with non sport joints, which only have 10mm bolts, not the 12mm on the sport.
They would obviously still fit the wishbone, but could move.
 
Fixed!!
I will go against the online tradition and actually update the post with the solution lol
Ordered some "Sasic" outer ARB bushes as I've been told the Renault one aren't sold anymore,
Installed those and no more noises yet.
It is possible that the fault wasn't the Powerflex bushes, but the fact I greased the outside of them during installation. The new "Sasic" bushes were greased only on the inside.
 


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