Knocking/Rattling From Rear - LCR

[Oliveracc]

Yesterday I had front and rear Eibach anti-roll bars and Koni FSDs fitted to my LCR.

However, since then there has been a knocking/rattling noise coming from the rear of the car. It doesnt occur all of the time, only when going over bumps.

The garage also noticed this after they had fitted everything, but they put it down to a few exhaust brackets that were broken. I had these brackets welded and repaired today, but the knocking noise is still there!

Bouncing the car at the rear and shaking the exhaust doesnt cause the noise to occur - it only happens when the vehicle is moving.

Any ideas what could be causing this?

 

[Reg]

I wonder if the top mounts are shot, the installation of new suspension finishing them off - unless they were replaced at the same time?

 

[Deleted member 7729]

Had the same on mine last night and it's only had the fsds fitted. I too haven't heard it again, but spent the day on the motorway. It was when i accelerated away and the rear went clunk

 

[Pabs]

Did you get your top mounts checked/changed when they were fitted?

 

[Deleted member 7729]

JKM fitted them, so I'll have to check with them

 

[Lee M]

Hi mate,

I have heard that the rear ARB can knock on the exhaust system, make sure that there is good clearence between them.

Remember that the exhaust will move quite a bit with the engine rocking.

 

[Pabs]

JKM fitted them, so I'll have to check with them

They won't just fit new parts unless you ask them to, as they'd need to go to SEAT to get the new ones anyway, and you'd then have to pay for them.

 

[Deleted member 7729]

Indeed, it was in for a 60k service and I left it with them. How much does it cost for new mounts? I'll keep an ear on the car and if it comes up again I'll speak to them

 

[Pabs]

The actual top mounts are about £15 each, but you need to remove the whole suspension to replace them.

Anyway, its probably not them anyway - I know i had a knocking problem with my FK coilovers, but not had the same with the FSD's.

 

[RobM]

Yesterday I had front and rear Eibach anti-roll bars and Koni FSDs fitted to my LCR.

However, since then there has been a knocking/rattling noise coming from the rear of the car. It doesnt occur all of the time, only when going over bumps.

The garage also noticed this after they had fitted everything, but they put it down to a few exhaust brackets that were broken. I had these brackets welded and repaired today, but the knocking noise is still there!

Bouncing the car at the rear and shaking the exhaust doesnt cause the noise to occur - it only happens when the vehicle is moving.

Any ideas what could be causing this?

Have you got the standard exhaust fitted? If so, Eibachs rear ARB is famous for knocking against this so this could be the cause of your problems. It works fine with aftermarket exhausts though as the backboxes are often smaller.

 

[Hooper]

The actual top mounts are about £15 each, but you need to remove the whole suspension to replace them.

Anyway, its probably not them anyway - I know i had a knocking problem with my FK coilovers, but not had the same with the FSD's.

Yes but they are a piece of p1ss to do, just un-bolt the bottom nut and bolt, undoe the top two bolts, which hold the alloy top bracket in place manouvre out, replace the top mount and bolt back in to the correct torque. Don't go near the front end though!!!

What about the trailing arm bushes? Are they in good order? Are the handbrake cables clear of the springs?

It's probably the exaust and the roll bar though.

 

[Oliveracc]

I've had the car up on ramps to see if the exhaust is hitting anything, but it isnt. You can give the exhaust a good shake in all directions and it doesnt hit anything.

Perhaps it is the top mounts? Although you can open both rear passanger doors, bounce the suspension quite hard on either side and again no knocking?!?!

I'm really stumped by this one.

 

[RobM]

Sometimes you can't recreate a problem by simply bouncing on the car or shaking the exhaust. It's not until the full weight of the car is moving on the road that you can replicate it.

 

[Ju.]

Are you sure there's no tell tale mark on the silencer?. I'd be very surprised if the exhaust wasn't knocking as I have the Eibachs and standard back box and it knocked like crazy, especially on speed humps.
I tried cable ties all over the place but the only way around it was a hammer.

 

[Oliveracc]

Ok guys I figured out what the problem is 30 secs after having a look myself (so much for garages...).

As Ju stated above, the rear Eibach ARB is hitting the start of the back-box. At most there is 1-2 inch clearance between the two when stationary. The red coating on the arb has been scratched off at exactly the point where the two are meeting.

Ju, did you just bash your back-box until they didnt colide? I tried this with a hammer myself today but the back-box is pretty strong so I reckon you would need to hit it very hard with a big hammer to make another inch or so clearance

Anyone got any ideas? (Other than buy a new exhaust!).

 

[Pabs]

well as you've said, most people put a big dent in the backbox to stop it fouling.
Otherwise they buy a new exhaust system. I don't really see any other options, unfortunately.

 

[Ju.]

It's easily done with a hammer you just need clearance to get at it.
Did mine 6 months ago and it's never knocked since.
Jack up the rear, drop it off the hangers and use a blow torch if poss to help soften the metal before WACKING it.

Julian