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Old 03-06-2015, 04:07 PM
FEP FEP is offline
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Default Clutch Delay Valve

Hi,

I need to replace the flexible clutch pipe on my car - clutch drag when hot.

Just had the under tray off to have a look. I can't see anything which looks like a clutch delay valve (thank heaven). Am I correct?

Thanks in advance.
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Old 03-06-2015, 04:23 PM
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Dave P Dave P is offline
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Yes there isn't a cdv as such but the hose itself act as one, if that makes sense,


http://www.z3mcoupe.com/forum/showthread.php?t=12697
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Old 03-06-2015, 04:46 PM
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Quote:
Originally Posted by Dave P View Post
Yes there isn't a cdv as such but the hose itself act as one, if that makes sense,


http://www.z3mcoupe.com/forum/showthread.php?t=12697
Not really - how does it do that?
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Old 03-06-2015, 05:01 PM
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Quote:
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Not really - how does it do that?
There is a restriction built into the hose.
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Old 03-06-2015, 05:02 PM
MasterMiller MasterMiller is online now
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http://www.zeckhausen.com/cdv.htm

explained
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Old 03-06-2015, 05:42 PM
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Quote:
Originally Posted by MasterMiller View Post
Excellent. This seems to suggest that no Z3M's had CDV's. That's not what others on this forum have found. Perhaps none in the US had them. BMW must have reckoned that US drivers were more able to handle a clutch that UK drivers!
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Old 03-06-2015, 07:35 PM
MasterMiller MasterMiller is online now
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I had my original hose replaced with an earls braided and definitely notice the difference now, especially when changing from 1st to 2nd. Got rid of the 'jerk' and feels normal now.
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Old 03-06-2015, 10:30 PM
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rsk289 rsk289 is offline
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Quote:
Originally Posted by FEP View Post
Excellent. This seems to suggest that no Z3M's had CDV's. That's not what others on this forum have found. Perhaps none in the US had them. BMW must have reckoned that US drivers were more able to handle a clutch that UK drivers!
Oh yes they had... or at least my UK spec S54 had. It is a fairly insignificant extra metal section built into the hose at the slave cylinder end. I got fed up with not being able to select gears easily, despite having changed gearbox oil and clutch fluid, so I replaced my hose with one intended for a lesser Z3 which does not have the delay valve. The gear change is greatly improved. When you get the old one off, have a close look at the slave cylinder end. You'll see how it works. It's a relatively easy job as long as you can undo the hose from the pipe in the engine bay. I ended up carefully hacksawing through the union longitudinally.
My E46 330i also has one, must get round to removing that too.
Roger
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Old 04-06-2015, 06:04 AM
siwilson siwilson is offline
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All Z3Ms had the so called CDV. Its not really a valve anyway. It's a restriction in the hose that slows down the fluid and as a result slows clutch engagement.

Here is a good thread form Bimmerfest on the subject.

FWIW, I have had a braided Earls hose on my S54 for 10 years now. One of the best mods I ever did.
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Old 04-06-2015, 08:07 AM
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Quote:
Originally Posted by siwilson View Post
All Z3Ms had the so called CDV. Its not really a valve anyway. It's a restriction in the hose that slows down the fluid and as a result slows clutch engagement.

Here is a good thread form Bimmerfest on the subject.

FWIW, I have had a braided Earls hose on my S54 for 10 years now. One of the best mods I ever did.
Thanks for that.

Looks like its Earls for me.

Surely it must be more than just a restriction - isn't the idea that it can disengage instantly but engages more slowly?
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