CDV Delete by UUC leaking brake fluid

[catchmerolling]

Hey all - I recently purchased and installed the CDV (clutch delay valve) delete from UUC, into my 1999 BMW E36 M3.

Although, after the install, the new CDV was slowly leaking brake fluid at the connection to the OEM clutch hydraulic hose (by the bracket). Video of leak here. To troubleshoot, I ordered a new OEM clutch hydraulic hose and UUC sent me another CDV delete, but still the leak persisted. I ended up reinstalling the old OEM CDV and the leak stopped.

I tried again for the third time using liquid thread lock, and I'm still getting the same slow leak. This was an easy install, and I'm confident everything threaded properly. I've purchased all new connections, and I'm still getting a leak with the UUC part. But the OEM CDV works just fine.

Any ideas / solutions would be appreciated, I really want to complete this install, thanks.

CDV Valve - OEM vs UUC.jpgClutch hydraulic hose - OEM Part 21522282355.jpg

[importbanana]

When I did the CDV delete on my 328 i just removed the OEM CDV and connected the line back together. You can just remove it, no parts necessary. Is it different on the m3?

[catchmerolling]

Ah you’re probably right. I’ll try that tonight and confirm if it’s successful. Thanks!

[blckstrm]

When I did the CDV delete on my 328 i just removed the OEM CDV and connected the line back together. You can just remove it, no parts necessary. Is it different on the m3?

Not different on the M3. You just remove it and reconnect the hard line to the hose. Good time to install a stainless braided hose by the way.

I'll note it's extremely disappointing that ANYONE sells a CDV delete. It's almost like being charged for blinker fluid...

[Calypsorotragto]

Yeah no kidding I can't believe people would pay for that, I get my blinker fluid for free when I spend at least $100 on parts....

Seriously, it's even more disappointing when the unneeded part they sell is defective.

[XnWarden]

As a general note, thread sealant will not do anything for a flared connection. The sealing comes from the surface to surface mating of the flare, not the threads. If it's leaking, then something is wrong with the flare.

As others have said, throw that piece in the garbage and just connect the metal line to the slave with no cdv.

Sent from my SM-G975U using Tapatalk

[catchmerolling]

Thanks everyone - you were all correct. I simply connected the clutch line to the slave and chucked the CDV in in the trash. Thanks for all the help, clutch feels way better!

One more question - is it necessary I install a stainless braided hose at this point? Is there too much pressure on the OEM rubber hose?

[blckstrm]

Thanks everyone - you were all correct. I simply connected the clutch line to the slave and chucked the CDV in in the trash. Thanks for all the help, clutch feels way better!

One more question - is it necessary I install a stainless braided hose at this point? Is there too much pressure on the OEM rubber hose?

How old is your old rubber hose?

[Calypsorotragto]

Removing the cdv doesn't increase pressure on the hose..

[blckstrm]

The point is your hose is old and should be replaced. If you're going to spend the time and money, do it right and get a stainless braided hose.

[importbanana]

is it necessary I install a stainless braided hose at this point? Is there too much pressure on the OEM rubber hose?

I replaced mine with a stainless braided one and I could tell no difference afterwards. Maybe others could. If I knew that before I wouldn't have done it.

[Calypsorotragto]

I looked at my hose pretty hard when I did a master cylinder and with 202,000 miles on it I couldn't find any reason to replace it so I'm still running it

[jamrobin]

I did this years ago on my '99 M3, then a 318,then an E39, and most recently my E83 X3... I swapped out the clutch line for stainless braided every time. I don't think the line makes any difference in the shifting, but it on of those "while you are already going to gargle and shower in brake fluid you may as well... In Canadian terms the cost difference isn't even a case of beer and then you don't have to get soaked in the stuff again until you have to swap out your clutch LOL

[blckstrm]

I did this years ago on my '99 M3, then a 318,then an E39, and most recently my E83 X3... I swapped out the clutch line for stainless braided every time. I don't think the line makes any difference in the shifting, but it on of those "while you are already going to gargle and shower in brake fluid you may as well... In Canadian terms the cost difference isn't even a case of beer and then you don't have to get soaked in the stuff again until you have to swap out your clutch LOL

^this.

Also, when the rubber hose gets old it can swell instead of holding pressure and lead you to think your clutch is dead. They don't usually leak, fail, etc - they just balloon enough you can't disengage the clutch.

You can replace them with new rubber or you can go stainless braided - it doesn't really matter. Up to you how much to spend - how soon you want to worry about it again. But at these higher mileages- just do it while you're already taking the brake fluid shower. It's a no-brainer...

[Mike WW]

^this.

Also, when the rubber hose gets old it can swell instead of holding pressure and lead you to think your clutch is dead. They don't usually leak, fail, etc - they just balloon enough you can't disengage the clutch.

You can replace them with new rubber or you can go stainless braided - it doesn't really matter. Up to you how much to spend - how soon you want to worry about it again. But at these higher mileages- just do it while you're already taking the brake fluid shower. It's a no-brainer...

I've never had a clutch line fail by swelling, but no reason why it couldn't. I have had brake lines do it but there doesn't seem to be any consistent age correlation. They can swell tight enough not to let a single drop thru when they do go.

[blckstrm]

I've never had a clutch line fail by swelling, but no reason why it couldn't. I have had brake lines do it but there doesn't seem to be any consistent age correlation. They can swell tight enough not to let a single drop thru when they do go.

This happened to a friend's face car. Replaced everything, one at a time, and no matter what we did the clutch still wouldn't disengage. Finally I laid down under the car while he worked the clutch and saw the rubber line expand ever so slightly. He ordered a new line (stainless braided) and that was the culprit.

[123bmwm3]

Hey all - I recently purchased and installed the CDV (clutch delay valve) delete from UUC, into my 1999 BMW E36 M3.

Although, after the install, the new CDV was slowly leaking brake fluid at the connection to the OEM clutch hydraulic hose (by the bracket). Video of leak here. To troubleshoot, I ordered a new OEM clutch hydraulic hose and UUC sent me another CDV delete, but still the leak persisted. I ended up reinstalling the old OEM CDV and the leak stopped.

I tried again for the third time using liquid thread lock, and I'm still getting the same slow leak. This was an easy install, and I'm confident everything threaded properly. I've purchased all new connections, and I'm still getting a leak with the UUC part. But the OEM CDV works just fine.

Any ideas / solutions would be appreciated, I really want to complete this install, thanks.

CDV Valve - OEM vs UUC.jpgClutch hydraulic hose - OEM Part 21522282355.jpg

I had the same problem 3 months ago. I purchased and installed a UUC valve from ecstuning and it leaked. It was frustrating and I wasted many hours diagnosing the issue. I believe the female threaded portion of the UUC valve was too deep compared to the OEM CDV (female threads not shown in your picture), which prevented the UUC valve from creating a proper seal with the flared end of the hard line.

This picture shows the difference between the female threads of the OEM CDV and the UUC valve I purchased.
cdv.jpg

If you still have the UUC valve, measure the female thread depth and compare it to the OEM CDV female thread depth.

Like you, I determined the UUC valve is not needed and directly connected the hard line to the flexible clutch hose.