1 M CDV Delete - Holy Crap!!

[MrRoboto]

On the fence...man this is a 1/2 hour very simple job you can do in your driveway. Dont pay someone $200. Cost you no more then a bit of brake fluid and some time.

Maybe your driving style doesn't warrant such a modification?

[RaptorKTM]

200 bucks, my god they are trying to bend you over like a porn star

[ayao]

Originally Posted by RaptorKTM

200 bucks, my god they are trying to bend you over like a porn star

No doubt. Two respected indies no less. They both used as justification the fact that the system would have to be bled. I think part of the reluctance stems from there being a large disparity in opinions and techniques on how to bleed the system properly.

[firechicken99]

Originally Posted by ayao

No doubt. Two respected indies no less. They both used as justification the fact that the system would have to be bled. I think part of the reluctance stems from there being a large disparity in opinions and techniques on how to bleed the system properly.

I agree.... In one thread we have gone everywhere from bleeding the entire system including clutch AND brakes to opening the reservoir and pumping the clutch because it is a "self bleeding" system....... Everyones input is greatly apprecaited, it just makes it hard to figure out what really can/can't be done

[Dackelone]

You do NOT need to bleed the entire braking system. You only need to bleed the clutch circuit! And having a pressure bleeder like the Motive unit will come in handy!! Or you can jury rig something like by reverse bleeding the clutch by pump new brake fluid in FROM bellow at the slave nipple and up to the res. The trapped air wants to raise anyways... and this is the best way. I however did it with the Motive pressure bleeder and I was easy.


Go look at the "CDV Delete DIY" thread for lots of info on how to do this. This is the BEST mod for your buck. The clutch works so much better... its almost a crime that BMW puts these stupid valves on our clutches.

CDV delete DIY thread... (see page #5 for my photos)
http://www.1addicts.com/forums/showt...cdv+delete+diy


Dackel

[dorkdog]

First I feel a little like Spongebob, who occasionally for some reason is propelled from below the surface up into the rarified air of the atmosphere, because here I am in the 1M forum and I only have a 128.

I stopped in here because I am looking for more information on the delete, which I plan to do on my car.

I felt it necessary to post because it seems like everyone wants to avoid the most tedious part of the job (bleeding the system) and is avoiding it by saying it's not necessary.

There are two reasons bleeding is necessary, and I do not care about the pedigree of shops that do not bleed - just because someone does it a whole bunch of times and charges people for it does not make it right.

1. Air can be compressed; brake fluid cannot. Imagine putting a spring in the middle of your hydraulic lines, so that the pressure at the pedal is not efficiently transferred to the end of the pedal's travel. That's what air in the line does. By pressing the pedal, you're compressing the air in the system instead of moving the fluid - that's why air makes the pedal seem spongy. And if your pedal is not spongy after doing this, it doesn't mean it won't be after asll the tiny bubbles of air combvine into one big compressible one.

Second, air contains moisture. Water is the enemy in a system like this - it causes corrosion and a host of other maladies which can take time to develop. So when you're wondering "how come my ____ failed after only _____ miles", look back to your shop practices.

I have not yet done the mod because I am not yet sure I have the knowhow/tools/confidence to do it right and am planning on helping a friend do his brakes first so I can go through the bleeding process first. I know it is a simple mod but simplicity is relative. I view "you don't have to bleed the system" with the same level of understanding as "you can wait 15,000 miles between oil changes".

If warranted, my apologies for breaking the waterline.

[ayao]

I appreciate your perspective.

Originally Posted by dorkdog

First I feel a little like Spongebob, who occasionally for some reason is propelled from below the surface up into the rarified air of the atmosphere, because here I am in the 1M forum and I only have a 128.

I stopped in here because I am looking for more information on the delete, which I plan to do on my car.

I felt it necessary to post because it seems like everyone wants to avoid the most tedious part of the job (bleeding the system) and is avoiding it by saying it's not necessary.

There are two reasons bleeding is necessary, and I do not care about the pedigree of shops that do not bleed - just because someone does it a whole bunch of times and charges people for it does not make it right.

1. Air can be compressed; brake fluid cannot. Imagine putting a spring in the middle of your hydraulic lines, so that the pressure at the pedal is not efficiently transferred to the end of the pedal's travel. That's what air in the line does. By pressing the pedal, you're compressing the air in the system instead of moving the fluid - that's why air makes the pedal seem spongy. And if your pedal is not spongy after doing this, it doesn't mean it won't be after asll the tiny bubbles of air combvine into one big compressible one.

Second, air contains moisture. Water is the enemy in a system like this - it causes corrosion and a host of other maladies which can take time to develop. So when you're wondering "how come my ____ failed after only _____ miles", look back to your shop practices.

I have not yet done the mod because I am not yet sure I have the knowhow/tools/confidence to do it right and am planning on helping a friend do his brakes first so I can go through the bleeding process first. I know it is a simple mod but simplicity is relative. I view "you don't have to bleed the system" with the same level of understanding as "you can wait 15,000 miles between oil changes".

If warranted, my apologies for breaking the waterline.

[RaptorKTM]

I agree with the above, and I think anyone with brake fluid knowledge knows, water and brake fluid do not mix.

[ayao]

Originally Posted by yemski

Yup I'm in Norcal looking to do this mod. I emailed sonicms but didn't get a response. Anyone got suggestions?

Performance Technic in Pleasanton seems to have their stuff together and seem like a decent bunch of guys.

[Dackelone]

Originally Posted by dorkdog

...I felt it necessary to post because it seems like everyone wants to avoid the most tedious part of the job (bleeding the system) and is avoiding it by saying it's not necessary.

...I have not yet done the mod because I am not yet sure I have the knowhow/tools/confidence to do it right and am planning on helping a friend do his brakes first so I can go through the bleeding process first. I know it is a simple mod but simplicity is relative. I view "you don't have to bleed the system" with the same level of understanding as "you can wait 15,000 miles between oil changes"...

Just because someone posts something - do not believe it! There is no way you can replace or pull out the CDV without bleeding the hydraulic line to the clutch. I know I have seen some post you can... but you should not buy into that crap. IF you want your clutch to work 100% correct... BLEED YOUR CLUTCH!

I would HIGHLY recommend a "pressure bleeder" like the Motive unit before tackling this job. Its a real PITA job without using a pressure bleeder! Especially if you run the clutch slave feed line dry!! With a pressure bleeder there is no chance of that happening.


Here is how to replace or remove the factory CDV on a 135i. Its teh same for a 1M.


CDV delete DIY thread... (see page #5 for my photos)
http://www.1addicts.com/forums/showt...cdv+delete+diy


Dackel

[RaptorKTM]

agreed

[firechicken99]

Originally Posted by Dackelone

Just because someone posts something - do not believe it! There is no way you can replace or pull out the CDV without bleeding the hydraulic line to the clutch. I know I have seen some post you can... but you should not buy into that crap. IF you want your clutch to work 100% correct... BLEED YOUR CLUTCH!

I would HIGHLY recommend a "pressure bleeder" like the Motive unit before tackling this job. Its a real PITA job without using a pressure bleeder! Especially if you run the clutch slave feed line dry!! With a pressure bleeder there is no chance of that happening.


Here is how to replace or remove the factory CDV on a 135i. Its teh same for a 1M.


CDV delete DIY thread... (see page #5 for my photos)
http://www.1addicts.com/forums/showt...cdv+delete+diy


Dackel

Correct me if im wrong (it was a while ago i read this) but I am under the impression you could pick up a new CDV from the dealer for less than $20, easily punch out the restrictor valve and replace your stock CDV with the modified one. Or am I losing it?

[Dackelone]

Originally Posted by firechicken99

Correct me if im wrong (it was a while ago i read this) but I am under the impression you could pick up a new CDV from the dealer for less than $20, easily punch out the restrictor valve and replace your stock CDV with the modified one. Or am I losing it?

That IS exactly what I did! I used a 3mm punch to pop out the restrictor - it was very easy to do. Here are my pics (also in that CDV delete thread...)





restrictor in place...

[ayao]

Originally Posted by firechicken99

Correct me if im wrong (it was a while ago i read this) but I am under the impression you could pick up a new CDV from the dealer for less than $20, easily punch out the restrictor valve and replace your stock CDV with the modified one. Or am I losing it?

This is completely correct.

On a related note (in the spirit of beating a dead horse) one of the shops I talked to was pretty confident that the clutch is "self-bleeding" and thus doesn't really need to be bled. Is it that horrible a thing to just pump the pedal a zillion times until the feel comes back?

[bdaddylo]

Originally Posted by Dackelone

Just because someone posts something - do not believe it! There is no way you can replace or pull out the CDV without bleeding the hydraulic line to the clutch. I know I have seen some post you can... but you should not buy into that crap. IF you want your clutch to work 100% correct... BLEED YOUR CLUTCH!

I would HIGHLY recommend a "pressure bleeder" like the Motive unit before tackling this job. Its a real PITA job without using a pressure bleeder! Especially if you run the clutch slave feed line dry!! With a pressure bleeder there is no chance of that happening.


Here is how to replace or remove the factory CDV on a 135i. Its teh same for a 1M.


CDV delete DIY thread... (see page #5 for my photos)
http://www.1addicts.com/forums/showt...cdv+delete+diy


Dackel

+1 With a pressure bleeder, it's a one person job.

[Dackelone]

Originally Posted by ayao

This is completely correct.

On a related note (in the spirit of beating a dead horse) one of the shops I talked to was pretty confident that the clutch is "self-bleeding" and thus doesn't really need to be bled. Is it that horrible a thing to just pump the pedal a zillion times until the feel comes back?

...another lie. It is not!

The only thing is gravity. Air bubbles will raise, so that is what you shop meant. BUT... if you get enough air in the system... it will be very hard for that air to float upwards. And as we know... air does not compress - so you will have a soft pedal(until you bleed the clutch) or a clutch pedal that sits on the floor. Ask anyone who's bleed their clutch pedal and they will know the horrors of that pedal on the floor.


Dackel

[yemski]

Originally Posted by ayao

Performance Technic in Pleasanton seems to have their stuff together and seem like a decent bunch of guys.

Thanks did you get yours done there?

[ayao]

Yes. They were very accommodating and got me in/out quick. I did ask them explicitly to bleed the clutch, though.

[firechicken99]

I wish I had known about this before switching to RBF600 last month. Want this mod but hate to waste 90% of a bottle of brake fluid :/

[bdaddylo]

Originally Posted by firechicken99

I wish I had known about this before switching to RBF600 last month. Want this mod but hate to waste 90% of a bottle of brake fluid :/

You're driving the wrong car if you're worried about a $20 bottle of brake fluid.

[ozinaldo]

Originally Posted by ayao

This is completely correct.

On a related note (in the spirit of beating a dead horse) one of the shops I talked to was pretty confident that the clutch is "self-bleeding" and thus doesn't really need to be bled. Is it that horrible a thing to just pump the pedal a zillion times until the feel comes back?

And there is also the 20 $ option from BMS etc. that looks similar to OEM but without delay valve and which in my understanding simply replaces the stock CDV part. Is bleeding still needed if we go that way?

By the way, why exactly we can't use the clutch stop and CDV delete together? Never been there so sorry if that is a crazy question.

[ayao]

Originally Posted by ozinaldo

And there is also the 20 $ option from BMS etc. that looks similar to OEM but without delay valve and which in my understanding simply replaces the stock CDV part. Is bleeding still needed if we go that way?

By the way, why exactly we can't use the clutch stop and CDV delete together? Never been there so sorry if that is a crazy question.

Opinions differ but it's best to bleed the clutch to ensure all the air is out of the lines. Mike Miller of Roundel Tech Talk agrees with this when I asked him ("I would never remove a CDV without at least bleeding the clutch slave cylinder.")

This is because removing the CDV per se will introduce some amount of air into the system. If you replace the CDV with a modded one, or just hook the lines back up together without a CDV at all, some amount of air will get introduced.

The Motiv pressure bleeder is what allows you to do it by yourself versus needing two people to bleed (one person in the car pumping the clutch as another person is underneath opening the bleed valve.)

You can use the stock CDV and pop out the restrictor, you can buy the one from BMS, you can send a stocker to Zeckhausen to exchange for a modded one, I think they're all equivalent.

I know people who are using both a clutch stop and a CDV delete together. They do different things, so it's no problem. The CDV mod just makes the car shift 1-2 the way a normal car is supposed to, without the clunky and annoying delayed engagement. I found the difference not night-and-day, but noticeable and preferable. The clutch stop just changes the overall amount of travel in the pedal for a sportier feel, I guess.

Hope this helps?