BC coilover rear knocking

[TomROW]

Hi

My 182 is currently at a garage having BC coilovers fitted. The garage is a specialist in suspension setup and tuning including British touring cars so I am assuming they know what they’re doing, though they don’t do many Clios.

They have fitted a set of BC coilovers but on test drive there is a knocking from the rear.

They think the issue is the top mounts but can’t resolve it.

Is there supposed to be spacers for the BC coilovers? As you can see from the pictures they sent there’s a difference in the size and design of the standard vs BC top mounts, but they can’t just use the original mounts due to a diameter different in the strut.

Thanks for any help, leaving my car there until it’s sorted!

 

[Eyysee]

@TomROW did you ever get to the bottom of this? Having similar knocking

 

[RallyXmad]

If you have the metal spacers installed on the springs to raise the ride height, could it be these knocking?

 

[Mr Trailer Man]

@TomROW did you ever get to the bottom of this? Having similar knocking

I've installed BC's on few Clio's for people now.

Can't say I've ever had any knocking issues.

Take some pictures of the rear springs on their mounts and it might help identify the problem.

 

[MaxB]

I’m having the same issues after fitting BCs on the rear of mine. A knock from the rear over sharp bumps.
Got the springs fitted with the bc supplied rubber spring locator on the top of the spring with the oem rubber isolator and the adjustment cup on the bottom.
Seems to be worse the harder the dampers are set

 

[Eyysee]

I am starting to think that it might be the rubber top mounts that came with the rears. The shaft body is slightly wider than OEM so the standard rubber top mounts don't fit [I know some folks drill them out to suit] and BC supply the top and bottom rubber mounts for the rears. However with the OEM mounts, there is a metal sleeve that sits in the middle and as the BC's are slightly wider, this sleeve doesn't fit [so I don't have this in place]. I am starting to think that given the top nut compresses only the top and lower part of the rubber, it might be causing some knocking given it doesn't clamp down onto the inner sleeve part.

This of course is only a theory but I have no idea where I would get a sleeve that would suit as I'm led to believe that even the likes of the powerflex mounts would come with an OEM sized sleeve and wouldn't fit the BC's. The part in the middle of the picture below.

 

[Mr Trailer Man]

I’m having the same issues after fitting BCs on the rear of mine. A knock from the rear over sharp bumps.
Got the springs fitted with the bc supplied rubber spring locator on the top of the spring with the oem rubber isolator and the adjustment cup on the bottom.
Seems to be worse the harder the dampers are set

I'm sure the black metal ring with the red sticker goes on top.

 

[MaxB]

I'm sure the black metal ring with the red sticker goes on top.

Tried it on top when I first fitted them and still had the same issue unfortunately. Doesn’t help when they don’t come with any fitting instructions

 

[Mr Trailer Man]

Tried it on top when I first fitted them and still had the same issue unfortunately. Doesn’t help when they don’t come with any fitting instructions

Ahh ok, all i know is that it says on that sticker to have it on top.

I never had any knocking with mine and i've fitted some for @lee M4RSH and @Brett recently with no issues.

Have you been able to tighten the lower shock bolt properly, they can be a pain with the Whiteline ARB in the way.

 

[Eyysee]

@Mr Trailer Man , in relation to my post above, did you encounter this when fitting the rears?
I.e. just using the upper and lower rubber top mounts and compressing them with the upper shock bolt without the metal sleeve in the middle?

Trying to see if going down a rabbit hole here is worth the effort.

The bit circled in red below. BC supply the upper and lower but there is no metal sleeve that sits in between. So when you tighten it down, it just compresses the rubber.

 

[Mr Trailer Man]

@Mr Trailer Man , in relation to my post above, did you encounter this when fitting the rears?
I.e. just using the upper and lower rubber top mounts and compressing them with the upper shock bolt without the metal sleeve in the middle?

Trying to see if going down a rabbit hole here is worth the effort.

The bit circled in red below. BC supply the upper and lower but there is no metal sleeve that sits in between. So when you tighten it down, it just compresses the rubber.
View attachment 1779891

Ones i've done were fitted as supplied by BC.

They do compress a bit.

Worth noting/checking that the rubber lip is sitting in the hole.

 

[MaxB]

Ahh ok, all i know is that it says on that sticker to have it on top.

I never had any knocking with mine and i've fitted some for @lee M4RSH and @Brett recently with no issues.

Have you been able to tighten the lower shock bolt properly, they can be a pain with the Whiteline ARB in the way.

Yeah I’ve torqued it up to 105nm but might try it without the whiteline arb and see if that helps.
When you fitted the top mounts how tight did you tighten them? I ended up bottoming out the thread on the top mount as the rubber compresses so much.

 

[Mr Trailer Man]

Yeah I’ve torqued it up to 105nm but might try it without the whiteline arb and see if that helps.
When you fitted the top mounts how tight did you tighten them? I ended up bottoming out the thread on the top mount as the rubber compresses so much.

Tightened until it stops.

I ran the dampers on full soft on the road, that might help.

 

[MaxB]

Tightened until it stops.

I ran the dampers on full soft on the road, that might help

Yeah it’s definitely better on full soft. Have you adjusted the length of the rear dampers at all when you’ve fitted them in the past?

 

[Mr Trailer Man]

Yeah it’s definitely better on full soft. Have you adjusted the length of the rear dampers at all when you’ve fitted them in the past?

On mine they were shortened a bit for less droop yeah, when it was setup at the alignment place.