DIY Clutch Delay Valve (CDV) Removal

[MikeyG_U2]

I did this today and bleeding the clutch afterwards was definitely the most difficult part, I have some guidance below on what method worked for me to bleed the clutch.

Originally I planned to swap in a new Slave Cylinder, but I did not have a good way to remove the top bolt on the OE slave cylinder, so I reverted to simply removing the CDV and Spacer from the OE slave cylinder. If anybody that has replaced the slave cylinder has tips on how they accessed the top bolt, I would love to hear it.

I will suggest to any others in the future that you want a #8 or maybe #7 size Wood Screw to grab the CDV and Spacer with. I started with a #9 I had handy and it was too big to bite the CDV. I then grabbed a #8 and it worked great.

Now for the bleeding:

I have a vacuum bleeder that was not very helpful in bleeding the slave cylinder, it did not seem to be able to draw any fluid on its own. This is the first time I've used this bleeder, a Four Uncles model that attaches to an air compressor to generate the suction, so maybe I did something wrong. On other cars I have used an old hand-pump vacuum bleeder without issue, but I got rid of that a few years ago during a garage purge as it was falling apart.

I ended up using the 2-person method with my wife in the car slowly pumping the clutch while I was underneath monitoring for bubbles coming out of the bleed valve. I did need a full half-turn to loosen the bleeder valve before any fluid started to come out, it wasn't a big turn, but with the limited space it is a lot of little wrench movements. I did use the reservoir filler that came with my vacuum bleeder to keep the brake fluid reservoir full, that allowed us to work quickly without having to stop and top off the reservoir repeatedly. If you are using this method, make sure you have some method of keeping the reservoir at maximum, either using a gravity filler, or just stopping every few pumps of the clutch to top it off by hand. My gravity filler over-filled the reservoir a bit, but I just the vacuum bleeder to remove any excess before closing it up.

Most of the time while pumping the clutch my wife had to pull the pedal back up as it would not self-return. Once there were no more bubbles coming from the bleed valve (probably after about 15 pumps) I had her hold the clutch to the floor while I closed the bleeder valve on the Slave Cylinder, and closed up the Brake fluid reservoir. Then I had her release the pedal, but it did not return at first, but after pulling it out manually one time it returned to normal operation and began to self-return. I then took it for a drive and everything felt great! No squishiness in the pedal.

The final results are I finally have smooth shifts, especially that 1-2 shift!! I've been driving stick for over 25-years and this car made me feel like an amateur the way it came from the factory, now it feels normal.

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[Spart]

Originally I planned to swap in a new Slave Cylinder, but I did not have a good way to remove the top bolt on the OE slave cylinder, so I reverted to simply removing the CDV and Spacer from the OE slave cylinder. If anybody that has replaced the slave cylinder has tips on how they accessed the top bolt, I would love to hear it.

My advice from earlier in the thread:

Remove the bottom bolt on the original slave installed in the car first, which will also release the bracket for the clutch line. Once that is done, have the new slave ready and disconnect the line from the old slave and immediately connect it to the new slave to keep the clutch master from emptying it's contents via gravity. You could also clamp the rubber line to prevent this as much as possible.

Let that dangle freely out of the way while you work on the top bolt of the original slave. Not having the hose connected makes this a bit easier, there will be continuous pressure on the bolt from the preload spring inside the slave. My bolt had a bit of blue loctite on it as well.

You need a u-joint or a wobble socket.

 

[BrodoFratgins]

Now for the bleeding:

I have a vacuum bleeder that was not very helpful in bleeding the slave cylinder, it did not seem to be able to draw any fluid on its own. This is the first time I've used this bleeder, a Four Uncles model that attaches to an air compressor to generate the suction, so maybe I did something wrong. On other cars I have used an old hand-pump vacuum bleeder without issue, but I got rid of that a few years ago during a garage purge as it was falling apart.

I spent a good 5 hours trying to figure out why I couldn't properly bleed the clutch with not one, but two different types of vacuum bleeders (air comp. and hand pump version).

Ultimately it was because, from what I read on some other BMW forums, the outlet line for the clutch on the reservoir is much higher than you would think. I had to constantly keep it filled to the literal brim, use the hand pump a few times, go back and top off.... rinse and repeat.

Not sure if it's the same as what you dealt with, but all in all I've been told this would have been far less of an issue with a pressure bleeder like Motive.

So in case anyone is dealing with what I and MikeyG dealt with.... be sure to keep the brake fluid reservoir filled all the way to the brim while you bleed.

 

[Spart]

Not sure if it's the same as what you dealt with, but all in all I've been told this would have been far less of an issue with a pressure bleeder like Motive.

I can't recommend the Motive 0109 enough.

 

[MikeyG_U2]

You need a u-joint or a wobble socket.

I actually bookmarked your post months ago planning for this day, and did my best to follow your guidance.


I tried using both wobble extensions and u-joints on the top bolt, but I could not find the right combo to get a good purchase on the bolt. It was really tough work in there and eventually I realized if I am having this much trouble getting the top bolt out, I'll never get it back in, so then I changed course. I'm happy with result, and now that I've experienced shifting without the CDV cannot imagine ever wanting to 'restore' it, so I'm happy with the outcome.

I kind of wonder if I would have had better luck with ratcheting wrenches instead of using a socket/extension combo, but those aren't in my toolbox yet.

 

[Muldoon]

Just wanted to add to the thread - this was super simple. Most of the time was spent getting the front of the car on jack stands. This clutch is very easy to bleed, nothing to be nervous about.

I did this 200 miles into ownership, highly recommended.

 

[BimmerGuy]

Yes, I read all ten pages of this thread. Interesting stuff. It's also interesting how much our skills vary, some folks can do this (allegedly) In 10 minutes, others it takes days getting the air out, connecting things properly, etc.

I don't get my car for a couple of days yet, but I have done this at least twice IIRC on real actual BMW cars, and it's a real PITA crawling around on the ground working in that tight area with fluid running down your arm. Well, my arm anyway. In both cases I just got the replacement E90 slave.

In my last three BMWs (M2 & M4s) I just didn't bother with it at all. It was really, truly horrible in the M2, but the clutch in the M4 was a bit more tolerable and I learned to deal with it. I do a fair amount of track driving, but I don't "race" and I'm not out to set records, so if it takes me a second and a half to shift, I don't get all bothered about it.

I do concur though, that the CDV is the bane of all enthusiasts and the engineer(s) that came up with this nonsense should be forced to drive a Prius for the remainder of their lives.

I will add FWIW that as noted, bleeding can be an issue, largely due to where the bleed screw is on the slave, plus the cramped conditions. I just let it gravity bleed, and didn't have any further issues.

 

[spaghettihoes]

Yes, I read all ten pages of this thread. Interesting stuff. It's also interesting how much our skills vary, some folks can do this (allegedly) In 10 minutes, others it takes days getting the air out, connecting things properly, etc.

I don't get my car for a couple of days yet, but I have done this at least twice IIRC on real actual BMW cars, and it's a real PITA crawling around on the ground working in that tight area with fluid running down your arm. Well, my arm anyway. In both cases I just got the replacement E90 slave.

In my last three BMWs (M2 & M4s) I just didn't bother with it at all. It was really, truly horrible in the M2, but the clutch in the M4 was a bit more tolerable and I learned to deal with it. I do a fair amount of track driving, but I don't "race" and I'm not out to set records, so if it takes me a second and a half to shift, I don't get all bothered about it.

I do concur though, that the CDV is the bane of all enthusiasts and the engineer(s) that came up with this nonsense should be forced to drive a Prius for the remainder of their lives.

I will add FWIW that as noted, bleeding can be an issue, largely due to where the bleed screw is on the slave, plus the cramped conditions. I just let it gravity bleed, and didn't have any further issues.

I used a vice grip to clamp the clutch slave cylinder line and lost a drip or two of fluid at most.

 

[lucky phil]

Yes, I read all ten pages of this thread. Interesting stuff. It's also interesting how much our skills vary, some folks can do this (allegedly) In 10 minutes, others it takes days getting the air out, connecting things properly, etc.

I don't get my car for a couple of days yet, but I have done this at least twice IIRC on real actual BMW cars, and it's a real PITA crawling around on the ground working in that tight area with fluid running down your arm. Well, my arm anyway. In both cases I just got the replacement E90 slave.

In my last three BMWs (M2 & M4s) I just didn't bother with it at all. It was really, truly horrible in the M2, but the clutch in the M4 was a bit more tolerable and I learned to deal with it. I do a fair amount of track driving, but I don't "race" and I'm not out to set records, so if it takes me a second and a half to shift, I don't get all bothered about it.

I do concur though, that the CDV is the bane of all enthusiasts and the engineer(s) that came up with this nonsense should be forced to drive a Prius for the remainder of their lives.

I will add FWIW that as noted, bleeding can be an issue, largely due to where the bleed screw is on the slave, plus the cramped conditions. I just let it gravity bleed, and didn't have any further issues.

Ha, as a general comment and not specific to the CDV what you are referring to is the internet forum "how long does it take" divisional factor. You take the actual time for any given task and divide it by a factor of 2-4 and quote that as the time it took you to do the job ,lol.
Its a variation on those Youtube videos where when the guy making the video gets to the tricky part or the difficult aspect of the job and you are interested to see how they tackled it and any useful tricks they might have up their sleeve it jumps to the outcome or next phase of the job. The magic of editing simply skips the part where the real mechanical skills and ingenuity come into play. And we all know why that is.
Phil

 

[spaghettihoes]

Yes, I read all ten pages of this thread. Interesting stuff. It's also interesting how much our skills vary, some folks can do this (allegedly) In 10 minutes, others it takes days getting the air out, connecting things properly, etc.

I don't get my car for a couple of days yet, but I have done this at least twice IIRC on real actual BMW cars, and it's a real PITA crawling around on the ground working in that tight area with fluid running down your arm. Well, my arm anyway. In both cases I just got the replacement E90 slave.

In my last three BMWs (M2 & M4s) I just didn't bother with it at all. It was really, truly horrible in the M2, but the clutch in the M4 was a bit more tolerable and I learned to deal with it. I do a fair amount of track driving, but I don't "race" and I'm not out to set records, so if it takes me a second and a half to shift, I don't get all bothered about it.

I do concur though, that the CDV is the bane of all enthusiasts and the engineer(s) that came up with this nonsense should be forced to drive a Prius for the remainder of their lives.

I will add FWIW that as noted, bleeding can be an issue, largely due to where the bleed screw is on the slave, plus the cramped conditions. I just let it gravity bleed, and didn't have any further issues.

The actual job itself did only take like 10 minutes to disconnect the line and get the part out.

Jacking up the car, removing the trim/undertray, putting them back on and bleeding the line made the job take a couple hours.

 

[Spart]

The actual job itself did only take like 10 minutes to disconnect the line and get the part out.

Jacking up the car, removing the trim/undertray, putting them back on and bleeding the line made the job take a couple hours.

Hell don't feel bad, it feels like it takes me an hour just to set up and tear down the MaxJax lift. ?

 

[lucky phil]

The actual job itself did only take like 10 minutes to disconnect the line and get the part out.

Jacking up the car, removing the trim/undertray, putting them back on and bleeding the line made the job take a couple hours.

Umm, all those things are part of the job. Try and convince the local auto tech forget lifting the car and accessing the component you're only going to pay him for the time to remove and install the part, nothing else.
Phil

 

[lucky phil]

Hell don't feel bad, it feels like it takes me an hour just to set up and tear down the MaxJax lift. ?

Speed, quality, cost....choose any 2. The mantra still applies.
Phil

 

[spaghettihoes]

Umm, all those things are part of the job. Try and convince the local auto tech forget lifting the car and accessing the component you're only going to pay him for the time to remove and install the part, nothing else.
Phil

Okay obviously... I'm trying to clarify what the 10 minutes people were referring to was for and the actual turnaround time for the job. But thanks for another one of your many useful contributions to this thread.

 

[lucky phil]

Okay obviously... I'm trying to clarify what the 10 minutes people were referring to was for and the actual turnaround time for the job. But thanks for another one of your many useful contributions to this thread.

Ok I misunderstood your post to a degree. You are correct in that the bulk of the time for this particular job to access the component and bleeding and a few hours for that seems realistic.
Phil

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