C4 Front RHS Knocking
02-22-2019, 12:53 AM
#1
Instructor
Thread Starter
C4 Front RHS Knocking
I'm after some help diagnosing a long term problem please. There are similar threads to my symptoms here which relate to planetary gears and it could be that, but I wanted to describe my symptoms as they are not exactly the same.
Car is an MY90 C4, RHD with 155k kms, spent all of its life on the East coast of Australia. Suspension is Bilstein B6 with H&R Springs (about 40k km's on them), D90's. I changed the sway bar drop links recently, this did not cure the problem.
I have a hollow metal clanging, knocking sound coming from the RHS suspension. I say hollow because it sounds like a metal sphere in a metal casing. It's not always loud, you can barely hear it over the engine and when the windows are down. You don't hear or notice it at high speeds, only really obvious at very low speeds, noticed this morning that at 20km/h it knocking away. It is much worse after a spirited drive through the twisties (noise is much louder), but can also occur once the car is up to temperature (does not happen when the car is cold/just begun driving). Once it was so bad after a long hard day of driving (Targa Tasmania roads), that I swear something had come loose and I jacked the car up to check, all was done up and tight. Was convinced something critical had come undone.
I also can feel the knocking coming through the steering wheel (just slightly but I can feel it).
Happens in a straight line and over bumps, does not get worse when turning. My driveway is a right hand turn over a blue stone entrance so it is bumpy with a slight incline and it clangs and knocks away. After coming home from a spirited drive and driving over the speed humps near my house, it is much louder. If it was the diff, i would think it would get worse when turning, or feel some resistance as the gear is impeded.
With the wheel off, you can grab the brake disc, give it a rock and back and forth and hear some knocking.
I have had this noise for about 18 months now, I can't say that it is getting any worse, it is has remained constant. There is no obvious resistance in movement or turn.
I took it to my indi this morning and was of course unable to replicate the noise while he was in the car. However, on a particularly bumpy section of road on my way home, it was present.
Any idea of where/what to check? Does it sound planetary gear related or suspension related?
Thanks in advance for your help.
Car is an MY90 C4, RHD with 155k kms, spent all of its life on the East coast of Australia. Suspension is Bilstein B6 with H&R Springs (about 40k km's on them), D90's. I changed the sway bar drop links recently, this did not cure the problem.
I have a hollow metal clanging, knocking sound coming from the RHS suspension. I say hollow because it sounds like a metal sphere in a metal casing. It's not always loud, you can barely hear it over the engine and when the windows are down. You don't hear or notice it at high speeds, only really obvious at very low speeds, noticed this morning that at 20km/h it knocking away. It is much worse after a spirited drive through the twisties (noise is much louder), but can also occur once the car is up to temperature (does not happen when the car is cold/just begun driving). Once it was so bad after a long hard day of driving (Targa Tasmania roads), that I swear something had come loose and I jacked the car up to check, all was done up and tight. Was convinced something critical had come undone.
I also can feel the knocking coming through the steering wheel (just slightly but I can feel it).
Happens in a straight line and over bumps, does not get worse when turning. My driveway is a right hand turn over a blue stone entrance so it is bumpy with a slight incline and it clangs and knocks away. After coming home from a spirited drive and driving over the speed humps near my house, it is much louder. If it was the diff, i would think it would get worse when turning, or feel some resistance as the gear is impeded.
With the wheel off, you can grab the brake disc, give it a rock and back and forth and hear some knocking.
I have had this noise for about 18 months now, I can't say that it is getting any worse, it is has remained constant. There is no obvious resistance in movement or turn.
I took it to my indi this morning and was of course unable to replicate the noise while he was in the car. However, on a particularly bumpy section of road on my way home, it was present.
Any idea of where/what to check? Does it sound planetary gear related or suspension related?
Thanks in advance for your help.
02-22-2019, 02:57 AM
#2
Rennlist Member
Geez, where do you start? I’ve had three noisy front end problems on my C4
1. Loose top bolt on suspension strut.
2. Broken ARB mount
3. Loose ARB mount bolts
There are so many bolts and moving parts in the front suspension it could be a loose part anywhere.
1. Loose top bolt on suspension strut.
2. Broken ARB mount
3. Loose ARB mount bolts
There are so many bolts and moving parts in the front suspension it could be a loose part anywhere.
02-22-2019, 05:36 PM
#4
Have you checked for front spring binding, felt in the steering, sometimes hitting a bump can release the spring tension if the front strut top mounts are old.
cheers
cheers