So, a little bit of a delayed response after mentioning my niggles on my new to me 2014 L405 Vogue SE SDV8 in this thread.

I pretty much have two issues I am aware of:

Problem 1
Knocking over rough roads/potholes. Coming from the L320 RRS world, the rearmost front lower arm suspension bush was nearly always the culprit and would be diagnosed with a few sharp dabs of the brakes. However, no knocking happens when the brakes are dabbed.

I notice through reading through some of the historic posts on the forum that the 2013 and 2014 SDV8s with the hydraulic ARBs typically exhibit this issue with the valve block being the usual cause as documented in LTB00557.

Problem 2
A very faint grinding/whirring/hissing when cornering, for example, around roundabouts. It sounds like it's coming from the rear of the vehicle. It is very quiet so the windows need to be up and the blowers switched off to hear it reliably. It's annoying nonetheless, especially when you know it's there and you're driving at night when it's quiet.

The only reference I can find in previous posts to something similar is in this thread which references LTB00588.

The dealer I bought from is a long way from me so they have agreed for the car to go to an independent near me to be looked at and quoted for resolving the issues. It's therefore going to BLR in Poole http://www.bournemouthlr.co.uk/ on Monday to be checked out.

Do you guys have any ideas on what the causes could be other than those I mentioned above? Kev

2014 L405 RR Vogue SE 4.4 SDV8 in Corris Grey
2010 L320 RRS HSE 3.0 TDV6 in Stornoway Grey

Last edited by knwatkins on 10th Oct 2020 4:01pm. Edited 1 time in total

Could be the valve block, but could just as easily be a suspension bush, or the ARB bushes. Mine had a knock on the front end, was fixed with 2 new LR rubber bushes for the Active ARB....cheap fix.

Cornering rear noise..... diff? Does it have the locking rear diff? There is nothing that can't be fixed with a hammer😜😜
FFRR 4.4 SDV8 Autobiography Santorini Black.
KIA E-Niro 4+
2021 Discovery 5 D300 MHEV commercial

Thanks for the advice. I'm hoping it does already have the revised valve block and it is as simple as a suspension bush.

That's a good point on the diff, it very well could be. It's not the electronic locking one as far as I'm aware, just the standard open one.

Do you know if these are prone to failing on the L405? I believe the pinion seals are prone to failure on the L405 and L494 so I hopped underneath the other day to have a look and I couldn't spot any leaks. Kev

2014 L405 RR Vogue SE 4.4 SDV8 in Corris Grey
2010 L320 RRS HSE 3.0 TDV6 in Stornoway Grey

Not heard of Many failing. That said Ryan On here just had his replaced on his tdv6. There is nothing that can't be fixed with a hammer😜😜
FFRR 4.4 SDV8 Autobiography Santorini Black.
KIA E-Niro 4+
2021 Discovery 5 D300 MHEV commercial

Welcome to the forum knw (great looking car btw), this was my recent thread that resulted in a new rear diff:
https://www.fullfatrr.com/forum/topic56221.html

We had an intermittent knocking noise too to the front n/s when going over things like speed bumps, uneven roads and it needed a new front shock absorber.

Thanks Ryan. Just had a read through your thread and there are some similarities. Mine only makes the noise when cornering however. If it turns out to be the diff when it goes into the indy on Monday, I wonder if they would strip it and rebuild it or whether they would just replace the whole thing. I appreciate the MD replaced yours for a new one.

With your knock on the front, did it seem like it was coming from the one corner? Or was it just generally from the front of the car?

Thanks again! Kev

2014 L405 RR Vogue SE 4.4 SDV8 in Corris Grey
2010 L320 RRS HSE 3.0 TDV6 in Stornoway Grey

A definite corner. It was obviously the front near side (passenger side) in our case

Hi , re the rear diff , can you check the history to see if the diff seal was replaced recently as if it was over tightened it can cause the diff to prematurely fail. 2015 4.4 AB
GSXR 1000 K5
R1 1998

So I have an update. It went in to BLR on Monday and they have said the diff is fine.

They have quoted to supply and fit a new ACE valve block to cure the knocking noise as per LTB00557 and also fit the insulators to stop the ACE pipes resonating against the deployable side step brackets as per LTB00588.

The supplying dealer has authorised the work to be carried out so fingers crossed, this will sort the issues and all will be well  Kev

2014 L405 RR Vogue SE 4.4 SDV8 in Corris Grey
2010 L320 RRS HSE 3.0 TDV6 in Stornoway Grey

Last edited by knwatkins on 10th Oct 2020 4:01pm. Edited 1 time in total

^^^
How much is the ARC block repair?

I have a knock/clunk on mine as well since I picked it up at 31k miles....now 36k on it. Definitely sounds like its coming from the front right. Curious to hear is the ARC block repair fixes it. I've heard it can be that or the bushings.

For rear diff I had to get a new pinion and seal on mine to stop a leak. 2014 FF Autobiography 5.0 SC
2008 FFRR (sold)
2008 BMW M5

The valve is £924 + Vat plus 3.5 hours fitting according to the quote plus a few litres of fluid. Kev

2014 L405 RR Vogue SE 4.4 SDV8 in Corris Grey
2010 L320 RRS HSE 3.0 TDV6 in Stornoway Grey

Do you happen to have the part #?

Let us know after the repair how it went/if it fixed it

Damn.....not a cheap part. and 3 hours?? Wonder how hard this would be for a DIY?

I replaced my ABS/DSC block on my e60 M5 which wasn't fun but doable

edit:
I found the following which talks about an insulation pad and threaded inserts?

RR (L405)
Knock' Sound
From Front Suspension
A 'knock' sound from the front suspension may be he
ard when traveling
over an uneven road surface. The sound may be notic
eable, when one of
the front wheels travels over a uneven surface whil
e the opposite front
wheel remains on a smooth surface. Install new insu
lation pad and
threaded inserts to repair.
9-May-14
LTB00557N 2014 FF Autobiography 5.0 SC
2008 FFRR (sold)
2008 BMW M5

Sure. The part number on the quote is LR072419.

3 hours sounds a long time to me too. I know on the L320 they used to be a pain to change because the pipes would corrode into the valve block. Perhaps it's the same on the L405 and they add time to consider this.

LR052713 is the part number for the isolator they will be fitting. There is no mention of threaded inserts  Kev

2014 L405 RR Vogue SE 4.4 SDV8 in Corris Grey
2010 L320 RRS HSE 3.0 TDV6 in Stornoway Grey

I put the L405 up on my ramps on the driveway earlier today. I wanted to take a look at where the dynamic response pipes come close to the brackets and cause the resonance when cornering as described in LTB00588.

I found that my front pipes already had the insulator fitted but the rear one did not. So, I simply shoved a rag between the bracket and the pipe...

Click image to enlarge

Do you have a pic to show where the valve block is located? How hard is it to get to? I’m assuming you’d disconnect the lines and lose all the fluid so you’d have to add new fluid. Does the system need to be pressurized or hooked up to so create/computer to do that or a simple swap the part and to off the fluid? 2014 FF Autobiography 5.0 SC
2008 FFRR (sold)
2008 BMW M5