Uncurable knocking!

[Gaverick]

For the past 2 years my car has had a knock from the front offside when going over bumps and when initially braking or accelerating. So far I have replaced almost everything on the front end except the bottom arms ( did change the ball joints) and track rods ( changed the TRE's though).

I've also got ktec engine mounts, a powerflex dogbone and pure Motorsport top mounts.

Does anybody have any idea what could be the cause? My next stop is to change the arms, but if that doesn't fix it all I have left is the track rods!

 

[Thrill]

I think I had the same problem, I think it was the CV joint in the end.

 

[Chri5]

When did you change the bottom ball joints?

I've used some cheap ones before and after only a couple of months 1 started knocking again!

 

[Advikaz]

Could also be a shagged top mount...

 

[Feates172]

Probably your solid top mounts. Try fitting standard ones to see if it cures it.

Had the same issue when I had ktec top mounts fitted.

 

[Gaverick]

I just put the solid top mounts on last night as part of my mission to stop the knocking, but its the same as the standard top mounts were.

I used Lemforder ball joints, do you think it could be those? I'll be getting new ball joints again as they come with the arms from Renault.

I put a new drive shaft in 7 weeks ago so that should rule out the CV joint.

 

[Lawro]

I have one too from the nearside front.

I have replaced all shocks with cup pack items, wishbone bushes, springs, ball joints, inner tie rods, track rod ends, Antiroll bar bushes, steering rack bushes and PMS top mounts and it still knows occasionally.

 

[Advikaz]

lemforder, good old ECP then?

 

[NorthloopCup]

To check if the cv joints are goosed grab hold of the driveshaft (with the car on the ground) and see if there's any in/out movement from the joint. It should have none.
Another possible cause of the knock could be the steering rack mate. It's internal so not a great deal you can do other than replace the rack.

 

[Gaverick]

I checked the driveshaft today as suggested and there was no in out play at all. I did find a hole in the ball joint boot though so I think the plan of replacing the arms next is the best bet, as I will replace both the ball joints and bushes.

I hope it's not the rack!

 

[172jack]

I had this on my ph1 I changed everything..shocks,ball joints..fitted solid top mount but still a bloody nock!!
But now I have found it after sooo long

is ur car lowered??

 

[dannyb]

Cant remember what the top mount is like on the clio but I had a similar thing on my megane after a few garages fitting and trying most things I cured it by spliting the top mount and fitting a tiny washer to space it slightly.

 

[Feates172]

Used to be an issue yeah, the new revised top mount solves that problem.

 

[Gaverick]

A friend thinks it could be a wheel bearing as he had a similar issue. There is no play in the bearing when jacked up but it does hum slightly on the motorway. The car is on Eibach Sportlines and 84k.

 

[-J-]

Also for knocking issues it's worth checking the engine and gearbox mounts.

Mine used to knock turned out to be the gearbox mount being worn.

 

[brisbane956]

Mine does the same, it has been looked at by various garages and they are all of the opinion that it is one of the characteristics of the PMS top mounts...

Mine only does it allow speed, as soon as you are moving at 30mph+ it stops.

 

[172jack]

Well after changing everything on mine I found out on my track day that it was the drive shaft nocking on the chassis of the car..I was shocked to find this as the problem and my car is only lowered 30mm and have only seen this happen on silly low cars but was a easy fix with a grinder and doesn't effect the structure of the car as it's jus excess metal.
so if you was to look on the offside front it's the lip of metal where the hose for the carbon canister runs along..there should be a plastic cover that u might need to remove but witch my drive shafts had started to wear through
i would 100% say this is the nocking noise you all are getting apart those who have nocking top mounts
I wish I had taken a photo before I cut mine back as after the excessive nocking on track it had bent this lip flat and made it clear that this was my source of the nock

 

[172jack]

Mine was also a low speed nock until raging it around brands hatch

 

[Gaverick]

OK so tonight I finally stopped the knocking and I'm over the moon, I can finally feel the benefits of my suspension refresh and it feels great, drives like new again!

It turned out to be a multitude of issues. The car was rattling badly and the outer CV boot had a hole and all the grease had came out so naturally I though the CV joint had failed and started fitting a new shaft. While doing this I noticed the ball joint boot had a hole and had a lot of up and down play do I popped to ECP and got a new ball joint.

Fitted it all together and went for a test drive and it was still rattling! Came back and jacked it up and noticed some slight play in my new solid top mount. Turned out the top nut had worked slighlty loose, so I retightened that with some thread lock.

Something I've realised is that when fitting PMS solid top mounts and experiencing noise from them a lot of people are just accepting this is part of the design. It isn't, the solid top mounts make no more noise than standard, if they do it's because they are amplifying the noise of an existing problem.

Also, despite all of these issues I couldn't detect any problem when just jacking the car up and having a poke around. Worth remembering if you are also having problems and can't figure it out.

 

[AlexW]

I actually came to find this thread between the forum crashing.

I too have PMS top mounts and had a rattle/knocking devlop, just happend to have the bonnet open earlier while lowering the car off the 2poster after doing a CV boot when I noticed the top mount move a little. Nipped up the top nut and my knocking has stopped too.