DRC hose replacement

[MostlyMonki]

So one of my rear DRC flexi hoses has perishes. I'm guessing as the oil will need repressurising it'll be a main dealer job? Anyone had it done before can give me an idea of cost?

[Doug_RS6]

If you open any part of the DRC it will need repressurised and the car should not be driven until it's done. Meaning that even though fitting the components is easy. You'd need to trailer the car the a dealer or suitable independent afterwards. From memory the hoses are expensive for what they are (basically a brake hose with fancy fitting) about £150 springs to mind. You may unfortunately find that once you fit one new component that another then fails quickly as it's the next weak link.

Sent from my SM-G960F using Tapatalk

[Jim Haseltine]

My car split a rear hose. Took it to the local Audi site and told them it had a split hose and asked them to deal with it.
During the work they discovered the OSR spring had broken - as I needed the car back on the road PDQ I authorised that work too.
The following is taken from the invoice dated June 3rd 2016, 5 years ago so prices will have changed a bit I think.
Carried out checks to leak from OSR suspension flexi Found split flexi pipe that requires replacement. £50. <<<< this annoyed me as I'd told them it had split.
Replaced OSR shocker flexi and bleed DRC system. £240.
Hydr Oil 1 litre £13.78
Tube 159.02 <<<< that's the flexi pipe

[Ranger4130]

I brought a renowned wreck, needless to say after I received it it became apparent the handling was quite “ship to shore” like. Upon further inspection offside rear DRC hose had rubbed on the tyre and had gone though. Zero pressure in the system. I couldn’t say how long it had been driven for in this state but I took a gamble and replaced the hose and had my local garage repressurise the system. Think the hose cost me £200 plus £100 to refill the system. System is now driving absolutely fine. Maybe I’m lucky (you wouldn’t think so with the amount of repaired I’ve done to this car) but my point being everybody will tell you the car can’t be driven without any oil in the DRC. I’m not recommending you drive it just saying mine can’t have had any it it certainly with its last owner that did maybe 3000 miles in it then I did a further 1000 miles prior to finding the system was empty. It’s been driven on empty, repaired and is 100% now.

[Doug_RS6]

Interesting read above. My understanding was that any amount of driving with the system low or empty would result in damage to the central valves. I must admit I do wish that Audi had just went with air suspension on the RS6.

[Phuketpaul]

Interesting read above. My understanding was that any amount of driving with the system low or empty would result in damage to the central valves. I must admit I do wish that Audi had just went with air suspension on the RS6.

Air may have been nice, with the adjustable ride height but I'd rather have the adjustable damping DRC than just air. The combination would have been awesome.

Just wish the sport mode was a little more pliant and thus usable, far too stiff for any road I drive on!

[welwynnick]

Can't sit on my hands any longer. DRC was a total engineering scam. MB ABC and BMW Dynamic Drive are the real McCoy, but DRC made the suspension worse, not better. I read the technical descriptions over and over again, trying to understand where the benefit came from, and there is none. It was marketing bullsh*t at the very best. Audi have since learned better, witness the new S8. The RS6 C6 crowning glory was undoubtedly its engine rather than its suspension.

Nicm

[Jim Haseltine]

The only slight benefit I can find for sport mode is that it gives my abs a good workout trying to keep my internal organs in place when driving along some of the roads around here. Apart for the few occasions I've got elderly passengers and it's set to comfort, my car runs dynamic.

[Doug_RS6]

Most of the roads here are too rough for anything other than comfort. Even then I'm weaving around like a drunk trying to avoid things. I've been contemplating fitness aftermarket air suspension. The only thing is my DRC is working and a decent air setup is around £3500. Another consideration is will it make the car hard to sell and you'd still need to get the KW modules to stop the error messages

Sent from my SM-G960F using Tapatalk

[Phuketpaul]

I fail to see why DRC was a scam.

DRC is just a mechanical system.of reducing roll and pitch and as far as I can tell works pretty well, as my car doesn't roll as much as you would expect a 2 tonne estate car too.

The sports suspension plus is the damping adjustment and that certainly works from soft and comfortable in comfort to rock hard in sport, meaning I use dynamic 80% of the time.

[Doug_RS6]

In all fairness. The DRC does a decent job of body control on a very heavy car. It also does a decent job of self levelling when the car is full of passengers and luggage. It's just a shame that the 3 settings seem quite far apart. It would of been nice to maybe have 6 stages of adjustment in firmness.

The biggest issue I have with the DRC is it makes what should be simple DIY jobs impossible. You can't remove a strut without the specialist equipment to recharge so a lot of simple suspension work is impossible.

BMW and Jaguar's alternative suspension setups managed a similar job with just an electrical connection to undo and no need for specialist tools. However it didn't self level.

Sent from my SM-G960F using Tapatalk

[welwynnick]

My objection to DRC is because it doesn't offer the benefits they lead you to expect. Ride and handling are usually compromised - you want firm suspension for body control and soft suspension for ride. BMW, Mercedes and Porsche use active compensation to get round that, and it does work. Audi claim that DRC achieves something similar with a passive mechanical system with diagonal damper connections, in a manner not entirely different to the Austin Allegro and it's predecessors in the '70s. Hydragas suspension allows a bump at one wheel to lift the car at the other wheel, which reduces the vehicle pitching and rocking for a given stiffness. Therefore you can increase the spring rate without making the suspension too bouncy. Except that DRC doesn't work like that. Fluid from the front dampers pushes a staggered piston that is larger than for the rear, so the net effect for certain speeds is that the gas spring fights the relative movement between the interconnected dampers. For low speeds where the accumulator valves offer little resistance, the interconnection works freely, and for high speeds it works like a rigid differential interconnection, which means the ride will be subject to more pitch and rock. I'm trying to think of a mechanical analogy of what is apparently a simple hydraulic system, but which actually has complex behaviour. The best I can think of is a pair of stiff anti-roll bars that are connected to each suspension strut by a hydraulic damper with a high pre-load, except that they're diagonally configured and tend resist pitch as well as roll. Since the wheelbase is greater than the track, and anti-dive geometry is more effective than anti-roll geometry, pitch isn't the problem that roll is (which BMW use to their advantage with their dynamic drive system). The net benefit is much the same as a pair of stiff anti-roll bars, but undermined by using dampers instead of rigid drop links. It's a perverse and schizophrenic system that contrives to make things worse rather than better, and is so complicated to understand that it's hidden behind a smokescreen of marketing obfuscation and hand-waving that successfully conceals what's actually going on. Obviously, somebody in Audi did figure out what was going on, and they changed to a Porsche type of system on the Q7 4M, and a kind-of-similar system to MB in the new S8 (to great effect apparently). DRC is frustrating, but the rest of the car is brilliant, and it won't stop me buying one.

Nick

[pimpinyourmum]

getting back to the OP's original question I have just had this done myself (last 2 weeks). The pipe from Audi (OSR) was £220 IIRC and the recharge was £275 inc VAT by Volksmaster in Bury.

Only thing is today I found the shock leaking. Turns out the thing was weak and it's blown the seal when the factory pressure has been put through the system. So, that's £780 fitted and another £275 for another recharge...ggrrrrrrrrr. All this is most annoying because when I found the initial leak I stopped driving the car and then went to the effort of trailering it myself to the garage to avoid driving it with low pressure/fluid. Perhaps if I had;t have done this it would have knackered the central pump of NSF shock? Yep - I'll console myself with that. On balance though I like the ride so I'm going to stick with DRC rather than switch to coilovers.