Question about CDV

Phil-E30

Active member
Hi guys,

Hoping to acquire a Z4 in the next while.

I was just wondering if someone could help me with the CDV I have read about when searching the forum.

What are the supposed benefits of removing it? Is it better to remove or alter it?

Thanks for the help!
 
Benefits are better control over clutch release and probably improved clutch life.

http://www.z4-forum.com/forum/viewtopic.php?f=25&t=1227
 
The valve has a very small diameter hole witch restricts the flow of oil. It's to protect the clutch from improper use. Great idea the problem is it can delay the action of depressing the clutch. If your used to driving a manual it can feel very weird. And can induce a bouncing motion if depress released and depress again.

The best thing to do is buy your car and drive it. If you have any problems with the clutch just mod it or remove it :thumbsup:
 
All helpful guys, thanks very much.

Is it an easy enough job to mod or remove? I am guessing the modification may involve some cost?
 
Phil-E30 said:
All helpful guys, thanks very much.

Is it an easy enough job to mod or remove? I am guessing the modification may involve some cost?

It's really easy to remove as long as you can use a spanner

No modification is needed you can remove the cdv and throw it in the bin. People only modify the cdv if its still in warranty period

The cdv was designed for stupid Americans who can't drive a real manual


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sam1832 said:
The cdv was designed for stupid Americans who can't drive a real manual

If that was the case I would think they wouldn't fit to cars destined for Europe. I think BMW fit as it just reduces potential shocks to the transmission.
 
srhutch said:
sam1832 said:
The cdv was designed for stupid Americans who can't drive a real manual

If that was the case I would think they wouldn't fit to cars destined for Europe. I think BMW fit as it just reduces potential shocks to the transmission.

... If you are not used to driving a manual lol


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Is it a case of just removing the cdv or has it got to be replaced with a link or something else?


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Mrbodger said:
Is it a case of just removing the cdv or has it got to be replaced with a link or something else?


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No the pipes reconnect with out it there




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It can be just removed. It's true about the mod just being for warranty work. But the mod is just drilling a larger hole.
 
Her you go: ( not my work, i had it stored on my HD from z4um.com )

First, have a look at both CDVs side by side.



Quite obvious, isn’t it ?

Tool list

1. 2x 17mm spanners.
2. 1x 7mm spanner.
3. 1x 10mm spanner.
4. Mole grips
5. Plastic tube.
6. Rags
7. Wife
8. Axle stand or vehicle ramp.

a. Jack up left hand side of vehicle, place axle stand or vehicle ramp under front left wheel and lower the car onto the axle stand or ramp. The low ride height prevents driving the z onto the ramp, so I jacked it on.

b. Locate the CDV (“A” in picture). Crawl under the car just behind the wheel. You will be able to spot the CDV close to the gearbox where a flexible (“B” in picture) meets a much smaller diameter rigid pipe (“C” in picture). The CDV is what couples the 2 together.




c. Locate the clutch slave cylinder, it is directly above the CDV, on the other end of the rigid pipe. On the slave cylinder is the bleed nipple (“D” in picture), recognized by the tiny rubber bung (“E” in picture) pressed over it. Top tip, open the bonnet, to produce more light!

d. Remove the rubber bung by pulling it off. Ensure at this point that your 7mm spanner is long enough to fit onto the bleed nipple and have clearance to rotate about 1/4 turn. Space is at a premium!

e. Locate the flexible hose, clamp the mole grips (see “F” in picture) onto it as close to the CDV as you can, this prevents fluid loss when you break the coupling.



f. Place one of the 17mm spanners onto the CDV (“G” in picture), locate the 10mm spanner (“H” in picture) onto the rigid pipe fitting at the CDV. Hold the 17mm stationary, rotate the 10mm to separate the rigid pipe from the CDV. There will be minor fluid loss at this stage from the rigid pipe.

g. Place a 17mm on the CDV (still “G” in picture), the other 17mm onto the flexible pipe (“I” in picture). This time hold the pipe stationary and rotate the CDV. Once again expect minor fluid loss depending on how close you got the mole grips to the CDV.





h. Refitting of the modified CDV is the reverse procedure.

i. Locate wife in drivers seat. Pump clutch pedal a dozen times. This forces the air to the bleed nipple. Check clutch fluid level and top up as necessary (I never had to).

j. Now push the plastic tube onto the bleed nipple. And as your assistance depresses the pedal open bleed nipple a 1/4 turn with the 7mm spanner, close the nipple before the clutch pedal finishes the downward stroke. Repeat this bleeding operation until fluid is seen in the tube (for me this was just the one time).

k. Wipe down all areas thoroughly. Depress the clutch pedal a further dozen times and check for leaks.

l. Check fluid levels. Remove from ramp, remove wife, enjoy revolutionized driving experience!

Total time 30 min.

Maybe it can be placed in the how to's :)

grts Kris
 
Phil-E30 said:
Hi guys,

Hoping to acquire a Z4 in the next while.

I was just wondering if someone could help me with the CDV I have read about when searching the forum.

What are the supposed benefits of removing it? Is it better to remove or alter it?

Thanks for the help!


so you find the idiot who is prepared to pay the asking price for your tt ? :lol: :lol: :lol:
 
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