It seems like quite a few people have had trouble with this. Mine is fine at the moment but having just bought it (a 2013 SDV8) I'm a bit anxious about this problem. Is it an inevitability that this will go wrong at some point (or were some OK and the others a dodgey batch?). If it is a dead cert that they'll fail at some point- does anyone know how much they cost to replace (or have a rough idea?). Also if it does fail , does it do any damage to any other components (eg the shocks).
Basically I'm wondering if prevention is better than cure! Any advice warmly welcome.
Thanks
Jon

Well, if you're worried and the car is still under warranty, I'd recommend fixing it. If it's your own $/£, and it won't cause damage, I'd wait until there's a problem unless you are expecting a long trip away from easy servicing.

thanks- it's not under warranty anymore. that's my problem. I Just wanted to get a feel for whether it's something the majority have had done or if it's just a handful of unlucky ones.

Hi You should ask your local Land Rover Dealer to check on the JLR system if the valve block has already been replaced under warranty or service bulletin. This will let you know if you need to worry about it. It is a big job and would cost heaps.
Plus! No it will not affect anything, but the clunking over bumps will drive you nuts if it is a faulty unit.
good luck !

It's not a case of them going wrong, the first couple of model years were wrong out of the box. The design of the ARC valve block was updated to include dampers. If you can't hear and feel knocking from the suspension over bumps then your car must have had the block changed at some point.

Do you have any more information on the ARC valve block please? I am struggling to get LR to do this but the car knocks like there are no rubber bushes in the suspension. Why it has to be such a challenge with LR. I mean why not do the job properly? Anyway, can you tell me what was incorrect with the original valve blocks please? 2006 S/C owned from new. Black, sand with black inserts. Shes a thirsty girl. ( now gone)

1972 Suffix A fully restored 2 door

1970, chassis number 26 the first of the press launch cars, Masai Red

2013 4.4SDV8 Autobiograpahy

My car still has a knocking from the front end but it's an SDV6 so I'm wondering if it even has the same valve block assembly as the TDV8. Can anyone clarify? I've had it back to the dealership many times for front end knocking and both uprights have been replaced as well as something about the active roll bars but never any mention of this ARC block. If someone could advise that would be much appreciated as it may help them identify the issue. Current Fleet;
2013 L405 Autobiography
2015 W205 C63 AMG
2007 AM Vanquish S
1977 911 Carrera 3.0 Targa Sport
1968 Alfa Romeo GT Junior race car

The V6 does not have ARC so if you have a knocking sound it's due to something different.

Thanks. That's what I suspected so thank you for confirming. The hunt continues! Current Fleet;
2013 L405 Autobiography
2015 W205 C63 AMG
2007 AM Vanquish S
1977 911 Carrera 3.0 Targa Sport
1968 Alfa Romeo GT Junior race car