How to modify your CDV (Clutch Delay Valve)

Hi, sorry to ask another stupid question regarding this but I am a bit mystified at present.

I am suffering from the jumpy, kangaroo type gear changes in 1st and 2nd which is rather annoying, about the only annoying thing with my 3.0i.

So, this CDV thing; some have said just remove it completely and others have said they have a modified one...I would rather just take it out if that works just as well?!

I've spoken to a local mechanic (Jerry at Clayton Cars - Bristol BMW Indy) who was about the only garage I spoke to that knew what I was on about. He said they had done it on M cars and recommended replacing the hose with a braided one and bleeding the clutch system. He said he didn't think my Z4 would have a CDV though which was a bit worrying. And when I mentioned others have got a modified one he said that might be a good idea to do the same. The instructions on page 1 and 2 all seem quite confusing to me, discussions over whether to take this out, leave that bit in, replace the hose, bleed the system, what is the insert, if removed completely connection could be too tight etc etc.

So, what do I need to get him to do in order for:

No more crappy gear changes
Not spending a fortune
Not having a broken car

Thanks in anticapation :oops:

PS - He's also changing my front fog light (Thanks ranski Rich :thumbsup: ) and said for both jobs would be an hour's labour, plus clutch bleed materials cost and potentially £25 for a braided hose...sound fair enough?
 
Cheapest solution would be to leave it alone and work around it! With practice you'll get the hang of it i'm sure.

If you do want to have the valve in, but not be restricted anymore you can buy one that's already been modified instead of modifying it yourself. If you want to have it look more OEM, for warranty reasons perhaps, then this is the best solution but if you dont then i really do think you should just chuck it away and be done with it.
 
yes you can drive around it....

but you will still sometimes forget :(

I modified mine and replaced with the help of a friend. The issue about modify/remove normally comes down to whether you have warranty or not
 
I don't mind spending the money just don't want to get ripped off! When Shidevil says his mechanic whipped it out and charged him £5 it raises eyebrows. Don't think I can live with it tbh, not when I've seen all the happy comments on here post removal of CDV...

I'm really not fussed about it looking OEM as it is not in warranty so that's no problem.

Is there any difference/pro's con's in taking it out completely or having a modified one?
 
The CDV is located under the passenger side of the car, Roughly where the door hinge is and about a 1/3 of the way across the car, You cant miss it.
Ideally a 2 man job to bleed it, same way you would your brakes, the Bleed nipple is located just above the CDV, The 3.0L one is PITA but still doable
 
Does anyone know the part number. I have searched realoem and bmwmini spares, and all I have come up with is 6770937 and a price of £61. Even been to the dealer but they couldn't find anything. I am right in thinking it is called a lock valve?
 
It is called an unlock valve, and apparently the price has went up. I check bavarian auto supoort and their price is now 87usd and it previously was only 34 usd.....not worth it for that amount.

However, the same thing can be accomplish by simply connecting the two lines together and just simply taking out the cdv....

Good luck
 
Hi there
I have had my 3.0si for 2 weeks now and lovin it to bits! Done led interior light mods, checked DISA valve, general clean up of engine bay and checking every fluid, nuts and bolts.... stopped some of the interior rattles (only some!) reset throttle (big improvement to driving and smoothness....
Now I come across the cdv valve. I do HATE the way it is 'jumpy' between 1st and 2nd and I cannot get a smooth gearchange, so this looks like the kiddy to change.
I am competent to take off the valve but can someone explain, in basic terms, how to 'bleed the clutch' afterwards.
Thanks.
 
I still havent got round to having this done, if im paying someone to do it what is involved and what should I expect to pay?

Ed
 
BluZiff said:
I still havent got round to having this done, if im paying someone to do it what is involved and what should I expect to pay?

Ed
Click to expand...

If your just having it removed

Have it done with a brake fluid change then I wouldn't of thought it wouldnt anymore than £70 for both

As it's a two minute job and if you changing fluid anyway you have to bleed it then

Sent from my GT-I9300 using Tapatalk 2
 
OK, just read through the whole post and still don't get it :cry:

Well, as I understand:

- it is located under de passenger's side
- It looks like a bolt with a groove in it
- you can remove it completely and just connect the hoses

The part that I don't understand (and never done before) is the "bleeding" of the system. That's really the part that is putting me off though I hate the wobbly gear changes between 1st and 2nd gear... Is it really necessary to bleed the system? Or can I just put clampts on the hoses while unbolting the CDV and reconnect?

I'd like to do it myself but don't want to do it wrong either...
 
It's impossible to do this procedure without introducing some air into the system, though clamping certainly minimises it, which makes bleeding a shorter process. Air in the system compromises clutch feel. Since the whole point of the CDV removal is clutch feel, I'd say it's pointless if you don't subsequently bleed the system.
 
Same as bleeding the brakes

There is a bleed nipple, you turn it half a turn to open it, push the clutch pedal to the floor, close it while holding the pedal on the floor
Let the pedal up

Repeat a few times

Obviously you need two people lol

The nipple is near the cdv

You will understand when you see it

You must get the air out otherwise it wont work

Sent from my GT-I9300 using Tapatalk 2
 
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