DIY: CDV delete for M Coupe/Roadster

[E368 S52]

This is a DIY guide with pictures for the CDV delete mod on an M Coupe/Roadster. I know there’s already a lot of info on this but I had to search and read 50 different postings to get all the info I needed.

Props go out again to Kelly (2kredz3) for helping with the install.
I was the camera guy and his assistant.


Things you’ll need:

PB Blaster: Spray the nuts and let it penetrate overnight
17mm Flare Nut Wrench
11mm Flare Nut Wrench
14mm Regular Wrench
7mm Regular Wrench: for bleeding the clutch
Z3 3.0 Clutch Hose (21 52 6 753 766)
2 Clamps or Vise Grips
2ft of Clear Tubing
Brake Fluid
Pan to catch Brake Fluid



First there are two areas that you want to clamp off to prevent your brake fluid from draining out your reservoir. See the 2 pictures below.





Jack your car up on the front driver’s side and make sure it’s secure since you’ll be getting underneath.

Here are pictures of the old clutch hose for you to see before you remove it.




Remove the end towards the transmission first. Make sure your drip pan is in place.


Now the end towards the reservoir.


This is how much fluid we had drip out from our old hose.


Here is a picture of the new clutch hose. Notice the size of the openings are the same on both ends where the fluid travels. You will need the 17mm Flare Nut Wrench for both ends.


Once the new hose is installed, you need to bleed the clutch. We did the 2 person pump method similar to when you bleed your brakes. The only difference was that I had to use my hand instead of my foot since the clutch pedal needed to be pulled back up after being depressed. We did that for 6-10 repetitions and on the last repetition, I depressed the clutch pedal only half-way down while Kelly tightened the nut. I then released the pedal.


Now drop the car back down and fill up the reservoir with brake fluid. Take it for a test drive and experience your clutch without the CDV.

[bluefire]

Good job and thanks for the write up.

What type of hose (clutch line) did you replace it with?

[E368 S52]

Good job and thanks for the write up.

What type of hose (clutch line) did you replace it with?

OEM Z3 3.0 clutch hose at $20 a piece. The part# is at the top of the post.

[2kredz3]

Props to a great dinner after the install

btw, added it to my DIY site

http://amsoil.the-mod-squad.org/mclutchhose.htm

[IRPancake]

nice writeup and pics. I also have the z3 hose, after my UUC busted. The shifts are definately smoother, but sometimes you can still feel how much the line balloons after a hard run

[A W]

Thanks for the pics, I have had my UUC line for over 2 years, just never had a chance to change it, this post gives me incentive to do it as it seems so simple. I have the power bleeder so that should make the bleeding job easier.

[bluefire]

OEM Z3 3.0 clutch hose at $20 a piece. The part# is at the top of the post.

NOTE TO SELF: Read....please read the entire post and stop looking at just the pictures!!!

[jbt56]

This is a great write-up, with very clear pics, BTW.

I have to ask, though, since I've never experienced a 'problem' with my clutch action, what is the actual result of this mod? The only thing about shifting my car I'd like 'better' is the actual shifting time- I find BMW boxes to be impossible to shift as quickly as, say, an Alfa, or even Toyotas, etc. I don't *think* that'd be the clutch. That's one reason I would never consider the BMW a drag racer. BTW, my '97 M3 felt exactly the same, so nothing's wrong with the coupe.

[Zacorias]

Great write up. I should've clamped the hoses when I did it but mine went pretty smoothly.

This is a great write-up, with very clear pics, BTW.

I have to ask, though, since I've never experienced a 'problem' with my clutch action, what is the actual result of this mod? The only thing about shifting my car I'd like 'better' is the actual shifting time- I find BMW boxes to be impossible to shift as quickly as, say, an Alfa, or even Toyotas, etc. I don't *think* that'd be the clutch. That's one reason I would never consider the BMW a drag racer. BTW, my '97 M3 felt exactly the same, so nothing's wrong with the coupe.

It makes the engagement much more predictable and gets rid of the slight "bucking" you get when engaging the clutch to late/early sometimes. It just improves the clutch engagement overall. Very valuable mod IMO.

[E368 S52]

Great write up. I should've clamped the hoses when I did it but mine went pretty smoothly.



It makes the engagement much more predictable and gets rid of the slight "bucking" you get when engaging the clutch to late/early sometimes. It just improves the clutch engagement overall. Very valuable mod IMO.

That's basically it. Very well worth it to me. At times the clutch would feel like it was slipping but that's been eliminated now.

When I first got the car it was impossible for me to drive it smoothly because the clutch engagement just didn't feel right. I eventually was able to adapt to it but it never felt completely right to me. Eliminating the CDV which is actually part of the hose and not a separate valve for the M's, made a big difference in clutch engagement.

[brm]

I put the UUC line in late last year, just before I stored the car for the winter. I did notice an immediate difference, but didn't have a chance to see how it affected daily use. I've now driven the car a few times this spring, and I just realized that it's much easier to drive because I don't have to think or worry about where or when the clutch is going to engage--it just engages consistently, the way it's supposed to, and the way it never did with the CDV (line, in this case). It makes it easier to take off from a light, engage at the proper r.p.m. when upshifting, and match revs when downshifting--all the things that used to make me feel like an idiot when the clutch engaged when it felt like it, not when I did. For getting rid of petty annoyances that negatively affect driving these cars, this and the seat-rocking fix rank high on the list.
Which is not to mention the difference actually having the tops of the shocks connected to the car makes, which is another story.

[jbt56]

Excellent descriptions! Now I know what the fix is for. It sounds like something I'll be adding to my list, as well, as I've experienced the questionable clutch engagement myself.
Thanks!

[GB5416]

How did I miss this post a month ago? Great write-up.

[TexaZ3]

Great write up. I should've clamped the hoses when I did it but mine went pretty smoothly.



It makes the engagement much more predictable and gets rid of the slight "bucking" you get when engaging the clutch to late/early sometimes. It just improves the clutch engagement overall. Very valuable mod IMO.

Is there any downside to this mod? I mean, BMW wouldn't put CDV just for fun of it.

[SunzOut]

The concensus is that BMW uses the CDV to reduce possible wear on drive train (under warranty) and increase wear on Clutch (no warranty).

[Cloudbase]

Great write up. This has been on my to do list for some time.

nice writeup and pics. I also have the z3 hose, after my UUC busted. The shifts are definately smoother, but sometimes you can still feel how much the line balloons after a hard run

Is the UUC line subject to failure? Was it the steel braided one?

[Finn]

yea this will be going on my todo list as well.

[MCoupeVet]

I have a 2000 Z3 M coupe. I do not see the CVD on realoem.com

Some other posts say my coupe does not have the CVD.

Question - Does my car have it?

Will this part fix it?
Z3 3.0 Clutch Hose (21 52 6 753 766)

[SunzOut]

I have a 2000 Z3 M coupe. I do not see the CVD on realoem.com

Some other posts say my coupe does not have the CVD.

Question - Does my car have it?

Will this part fix it?
Z3 3.0 Clutch Hose (21 52 6 753 766)

No spearate CDV on the M's - yes that is the part to revmove the "CDV" for the M's

[MCoupeVet]

No spearate CDV on the M's - yes that is the part to revmove the "CDV" for the M's

Thanks

[IRPancake]

Is the UUC line subject to failure? Was it the steel braided one?

Yes it was the braided one, and as far as I know I'm the only reported case of it happening. This is the very first mod I did to the car, and the shop I took it to were real pricks, telling me it wouldn't do anything and giving me a hard time about it, even though it took them 30 mins and got $70 to do it.

It worked fine for several months then the end where it attaches to the fitting split and made the car undrivable. My $30 hose turned into a $400 repair including towing and another shop to replace the hose. I wish I held off on it and learned to do it myself, I was just too afraid since I hadn't done anything on the car previously, now I'd do it in a heartbeat.

[razingkane]

No spearate CDV on the M's - yes that is the part to revmove the "CDV" for the M's

Here's a picture of the UUC SS hose for a MZ3 I accidentally ordered. One end of the hose has a small angled bend in it. It looks to me that the ends have different size holes. So I'm guessing the 1999 M roady has a CDV feature built into the hose as previously stated.

[rtav]

I'm confused - you ordered a UUC SS hose for your 99 M Roady that is not the correct part? If it looks like this, it is the correct part for the MZ3:



The SKU is SSCL-2 for that part.

[razingkane]

I'm confused - you ordered a UUC SS hose for your 99 M Roady that is not the correct part? If it looks like this, it is the correct part for the MZ3:



The SKU is SSCL-2 for that part.

Right.....I'm reading in this and other threads that if I want to get rid of the CDV built into the hose for MZ3's then I need to order a 3.0 hose. Apparently the 3.0 had and actual CDV valve instead of a CDV built into the MZ3 hose. The M versions had a hose with 2 different size holes.

That's what I'm reading. 2kredz3 is gonna tell me which hose to order so I do not have any type of CDV.

Geeesh I'm stating to get a headache. All I want to do is get rid of the CDV feature in my MZ3.

[JaBr1884]

Right.....I'm reading in this and other threads that if I want to get rid of the CDV built into the hose for MZ3's then I need to order a 3.0 hose. Apparently the 3.0 had and actual CDV valve instead of a CDV built into the MZ3 hose. The M versions had a hose with 2 different size holes.

That's what I'm reading. 2kredz3 is gonna tell me which hose to order so I do not have any type of CDV.

Geeesh I'm stating to get a headache. All I want to do is get rid of the CDV feature in my MZ3.

Yea it's a nightmare trying to figure all this out. I'm working with a few guys trying to get all this cdv info in a consolidated post. One that lets poeple know what they need to do, if anything, to remove the cdv. In time, this should be a lot easier to understand.