E46Fanatics (http://forum.e46fanatics.com/index.php)
-   DIY: Do It Yourself (http://forum.e46fanatics.com/forumdisplay.php?f=27)
-   -   CDV Delete DIY with pics (http://forum.e46fanatics.com/showthread.php?t=763107)

Scott87 05-09-2010 10:55 AM

CDV Delete DIY with pics
I know there are lots of these CDV delete threads around but this is just my experience and me practising making DIY threads :)

The Clutch Delay Valve (CDV) basically softens up the clutch pedal to remove the harshness of the engines power from the car. If you come off the clutch quickly to apply mucho power, the CDV will slow the clutch slightly to make the application less harsh. I wanted my clutch to kick hard when i lifted the pedal quickly, the rest of the time i am capable of managing it myself without some valve interfering. This DIY may seem long and complicated but honestly it isn't I have just been very thorough to make it really clear for people. Read through it and it should make sense, you're basically pulling two pipes off either side of the CDV and sticking them back together!

This job is VERY simple to do (really it is easy i would rate it 2/10).

You will need:
The car jacked up on stands at the front (and rear if you are of a large build to get under the middle section)
1 x 11mm spanner.
2 x 17mm spanner (please get two, this is important).
C-Clamp or mole grips.
Bottle of DOT4 rated clutch/brake fluid.
1 bleed kit (see my sig for brake bleed DIY for info)

With the car up on stands (please use stands for your own safety and not just the jack) crawl under behind the front wheels. Imagine right between the driver and passenger seat, where the under body covering panels end there is a little open space up the side of the clutch housing. There is only really one line/tube, it comes from the front of the car into a little bracket, after the bracket is a metal pipe that wiggles all over the show and then in to the back of a little cylinder (the clutch slave cylinder). Look at the pic below, it is the only thing that looks anything like this down there so should be really easy to spot it:


Just above this where the metal pipe runs to the small slave cylinder, there is a little metal tube sticking out with a small rubber cap on, this is the bleed nipple and will be needed later.

For now though on with the DIY!

Have a look at this pic, i have added some labels to make what i am about to say even more simple :)


Step 1
To the right of bolt number 3 (about 6") you need to clamp the line. Use a C-Clamp or some Mole Grips. Don't go mad, there will be no pressure in this line while you are working on it so just a gentle pinch to stop it flowing out. A slow drip is no problem just don't get it on you!

Step 2
Put your 17mm spanner on bolt number 2, this is just to hold it in place. Put your 11mm spanner on bolt number 1 and start to unscrew. Please note at this point you will start to get fluid leaking out, this is totally fine. Wear goggles if you feel you can't keep it out of your eyes. If it flows and flows and flows, check the clamp and make sure it's tight. I lost enough to fill a normal glass about 1". Once bolt number 1 is loose you can unscrew it with your fingers keeping bolt number 2 held with the 17mm. Once free gently pull the clamped section (bolt number 2) of the hose away, please note bolt number 1 actually extends INSIDE bolt number 2 so do not bend it as you do this.

Step 3
Grab your second 17mm spanner and put it on bolt number 3 (you did get 2 of them right...). Holding bolt number 3 in place, unscrew bolt number 2. Once loose use your fingers to unscrew bolt number 2. Once bolt number 2 is out you can stamp on it, burn it or keep it to remind you of your victory! This is the CDV. Look through it and look how restrictive the inside of the thing is, the lines going in are massive then this tiny pin hole inside there...

Step 4
Basically put bolt number 3 where bolt number 2 was. Poke the little pipe from bolt number 1 back through the bracket and using your fingers at first gently screw bolt number 1 and bolt number 3 back together. Nip them reasonably tight with the spanners but don't go wild. That is it! Your CDV is now removed :) You just need to quickly bleed the system to remove any air you let in when you opened the pipe up to remove the valve.

Handy to have a helper for 5 minutes here, all they have to do is press a pedal when you say so the better half can even do this! Make sure your brake/clutch fluid reservoir is full to MAX and sit the cap back on top. Pop the rubber cap off the bleed nipple and attach your chosen bleeding kit (see my sig for brake bleeding DIY with loads of info on bleed kits). Open the bleed nipple a half turn. Get your helper to slowly depress the clutch pedal and slowly bring it back up. Please note the use of the word SLOWLY. It should take around 4-5 secs to press it down and then 4-5 to bring it back up. On the first few strokes you should get loads of air bubbles. Once the fluid runs clear and bubble free tighten the nipple, remove your bleed kit and put the rubber cap back on the nipple. If you need to do 5 or 6 strokes check the reservoir fluid level and top it up. Once the job is done always fill the reservoir back to MAX.

Your work here is done! Put the car back on the ground and fire it up, go for a test drive. First time you set off please remember what the job you have just done will mean. I most certainly did NOT staul my car after removing the CDV and bleeding the system. This is also a perfect time to bleed your brakes and swap the fluid for fresh stuff. If you are going to do this check my sig for the brake bleed DIY, the clutch is bled after the brakes if you are planning on doing this.

Here is the CDV (bolt number 2) after i removed it:


I'm going to keep it to remind me of how it used to make the car feel.

Hope this helps you guys, any questions hit me up, happy to help.


Scott87 05-09-2010 11:11 AM

I have tried to construct this image to show a little better how the connections all hook up and basically you could do the DIY with this 1 image i think!


But it may be cr@p, let me know!


cabl3i 05-13-2010 12:32 PM

This is a great DIY gonna do this on saturday right after the oil change (figure it'll already be lifted so why not).

Only thing, where can I get a spanner? Any autoparts store?

Scott87 05-13-2010 12:40 PM

Yeah absolutely any car parts shop will have what you need. Just make sure you have two 17mm spanners or you will not be able to do it (ask me how i know). A lot of the other DIYs don't seem to say this.

Thanks for the comments and let me know how it goes!


snowcatxx87 05-13-2010 01:34 PM

Nice write up. BTW I didn't notice a change whatsoever when I did this a year ago.

Scott87 05-13-2010 01:42 PM

Once you take the CDV out if you look through it you can see how restrictive it is. The intakes on each side are quite wide then in the centre there is this tiny little hole. I agree that refreshing the fluid whilst i did mine contributed to the better feel after but removing it must do something otherwise BMW wouldn't pay to put it there. Just my thoughts :)

partialresponse 05-15-2010 02:44 PM

After removing mine (and it's very easy to remove, thanks to this detailed write-up) I'm rather surprised at how little (if any) difference it makes to my shifts. Maybe it's the way I shift - but even quickly dropping the clutch feels no different now from how it felt with the CDV in.

- Kofi

sillieidiot 05-15-2010 02:52 PM

nice diy. you forgot the disclaimer lol

RangerDave 06-26-2010 10:49 PM


Originally Posted by cabl3i (Post 11740451)

Only thing, where can I get a spanner? Any autoparts store?

A spanner is what the Brits call a wrench. OP is from the UK.

tony325ci_51 07-22-2010 05:58 PM

Nice write-up Scott. People looking for CDV delete info might find this thread too:


Scott87 07-23-2010 03:37 AM

Haha sorry for the confusion on spanner/wrench. Us Brits eh...

The fluid change made the clutch better in general. You should notice the CDV is gone when going from 1st to 2nd or 2nd to 3rd under heavy acceleration. This is the only time the CDV really slows the clutch enough for you to notice it's gone.

M00P 11-06-2010 11:41 PM

LOL. I was thinking I don't have a spanner...I'll just use a couple wrenches.

2003 325i 11-07-2010 07:21 AM

Scott, thanks for posting in my CDV delete thread. Thought I should add it here that if anyone else has troubles threading the steel line into the line in front due to rust/corrosion and they need to fix threads they need to have a 1.0 x 10 mm tap and die on hand. I replaced my steel line because it was too bad to remove easily. Actually had to put heat to the steel line nut to remove it from the CDV to get the bracket back. May as well add that the nut that holds on the bracket is 13mm.

RangerDave 11-07-2010 02:35 PM

I've owned my car for over three years and have always wanted to remove the CDV. Finally got everything ready and went under the car last weekend for removal but the CDV was not there! What a relief, but now I am curious if someone else had alredy removed it or if some early e46 (like my '00 preface-lift sedan) just didn't come with it.

phamine 11-08-2010 06:49 PM

So you don't have to bleed the entire brake system if you remove the CDV?

partialresponse 11-09-2010 08:55 PM


Originally Posted by phamine (Post 12442526)
So you don't have to bleed the entire brake system if you remove the CDV?

No, I don't think that's necessary.

- Kofi

2003 325i 11-14-2010 06:06 PM

no entire brake system bleed not necessary, just bleed the clutch.

luc 02-13-2011 02:28 PM

i want to hug whoever invented the cdv delete.. my car feels amazing without a cdv and with $5 clutch stop mod.

jkahng 05-11-2011 06:09 PM

I just did the cdv delete last night.
the clutch catches like it should. no more guess work on when to apply the throttle when i take off!!!

I think the valve restricts clutch RELEASE as well as engagement.
I have a habit of grabbing the shifter as soon as I start pressing the clutch. Previously, 1st gear was much harder to engage when starting from neutral.
Much smoother shifting now.

Everyone should do this mod...

kdiggs 05-11-2011 07:18 PM

Quick tip if you plan to do more DIY - use a higher quality camera. Other than that, great write-up.

All times are GMT -5. The time now is 12:59 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
(c) 1999 - VerticalScope Inc. All rights reserved.