[R32DBP]

Tried to do this mod today and I may have messed something up when reverse bleeding. :facepalm:

I was having issues pushing the fluid into the slave via the syringe because bleeder valve wasn't opened all the way. Kept having the syringe tube pop off and got fluid everywhere (doh).

Once I completely loosened the valve and was able to push fluid in through the syringe, I closed the valve and pumped the clutch. It just kept dropping to the floor and never went back to normal. I figured let me keep pushing fluid in since I kept losing fluid.

The final push and clutch pumping ended up spewing fluid all under the car. I think something happened to the slave and just leaked all into the bellhousing?

Any idea if I could just get another e90 slave and rebleed the system? or did brake fluid get onto the clutch? lol. Thanks for any help!

[Tchao]

I doubt the slave broke.
You most likely didnt bleed it. You will need to go under the car again to figure it out. Most likely just need another bleed. Once you get good pedal return, bleed it once more to ensure all air is out.

Make sure your:
-Brake reservoir is not full to the rim when you reverse bleed
-Keep the clutch pedal all the Way rearwards (like how it normally sits) when you bleed.
-Push fluid with no air in the syringe, and push enough fluid to flush any air all the way back up into the reservoir.
-Tighten the bleeder valve before you push on the pedal
-Top off your reservoir before you start pumping the pedal.

[R32DBP]

So I took the E90 slave out and it indeed did break. Took the cover off and the plastic snapped inside. The rod inside was basically popped out and thats how it leaked fluid.

I ended up putting the stock slave back but with the valve removed. It was easy enough to remove with a screw like in that youtube video that was linked previously.

Maybe I just got a faulty slave, I'm not sure what happen to it. Guess I gotta give FCP a call to see if I can return.

I will say that deleting the CDV is such a worthwhile mod. I don't get why car didn't come this way from factory ahah.

[kern417]

Originally Posted by R32DBP

So I took the E90 slave out and it indeed did break. Took the cover off and the plastic snapped inside. The rod inside was basically popped out and thats how it leaked fluid.

I ended up putting the stock slave back but with the valve removed. It was easy enough to remove with a screw like in that youtube video that was linked previously.

Maybe I just got a faulty slave, I'm not sure what happen to it. Guess I gotta give FCP a call to see if I can return.

I will say that deleting the CDV is such a worthwhile mod. I don't get why car didn't come this way from factory ahah.

Sounds like you may have mistakenly depressed the pedal without the slave installed. Regardless, glad you got it sorted.

[R32DBP]

Originally Posted by kern417

Sounds like you may have mistakenly depressed the pedal without the slave installed. Regardless, glad you got it sorted.

Actually it was installed. When I was pumping the pedal to bleed, it got stuck halfway. When I pushed it to the floor thats when I heard a crack/pop. I kept trying to bleed and that's when I saw the fluid under the car.

Definitely glad I was able to reuse the stock one with the CDV deleted. Love my car all over again haha.

[renizer]

Originally Posted by renizer

hey there,
so i know this is the F30 forum but just to get this right - the F series (except 1, 3, 4 series and X5/6 it seems, when looking up the slave cyl) has the same slave cyl as just about all the E series cars minus X5/X6 E.
So it seems to me, the cars that have this slave cyl have the CDV located in the stock line - like my E91: http://bmwfans.info/parts-catalog/E9...lutch_control/
Imo the diagram clearly shows the CDV in the line? So no CDV in the slave needed.

However, for the exceptions, like F30, the line does not have a CDV in the line. If you combine those CDV-less lines with CDV-less "E" slave -> no more CDV

Oh and I'm pretty sure BMW did this for drivetrain protection and longevity just as much as for "improved" driveability and NVH for ppl who prefer this laggy indirect shit over "sheer driving pleasure"

anyone have feedback on that? basically the question is: you use the E90 slave because it doesn't have a CDV and the E90 hast the CDV in the line? And the F30 line doesn't have a CDV but instead in the F30 slave?

[kern417]

Originally Posted by renizer

anyone have feedback on that? basically the question is: you use the E90 slave because it doesn't have a CDV and the E90 hast the CDV in the line? And the F30 line doesn't have a CDV but instead in the F30 slave?

Not really sure what' you're asking. Some people are swapping to an E9x slave because it doesn't have the CDV in it. It works for F-series 1/2/3/4 series. It has nothing to do with removing the slave from the E-series.

[renizer]

I know, I'm merely wondering if I could just use an E90 slave with the F30 line to delete it on my E9x

[kern417]

Originally Posted by renizer

I know, I'm merely wondering if I could just use an E90 slave with the F30 line to delete it on my E9x

...just remove it from the E90 line. Why replace the line when you don't need to?

[bitcore]

I have a 2021 F87 M2 competition with a manual transmission.

This mod is absolutely essential. The metered valve installed in the slave clutch cylinder on the M2 competition 6MT is absolutely tiny, about the size of a pin head. It appeared smaller than the CDV on my E82 135i! The difference felt after installing the E90 part is incredible. I can now drive this car "smoother than an automatic" according to my partner. My passengers feel much more comfortable and their necks no longer hurt from the uncontrollable herky-jerky-ness of 1, 2 and 3rd gear shifts.

I found this bleeding thread to be very useful: https://f87.bimmerpost.com/forums/sh....php?t=1646233

Bleeding tips from me: I used the motive power bleeder, since I had one. I recommend a power bleeder, it makes this and brake bleeds a 1-person job. Fill the reservoir above the max line, but not overflowing and try to pre-populate most of the power bleeder's hose with brake fluid before screwing the fill cap to the reservoir. At least on the Motive product, it's OK and actually great (for pinching the line off to remove the cap when you are done to minimize spills) if you can have an air bubble of a few inches in the line in the high spot where the line will arc away from the fill cap. The line is thick enough that you don't need to worry about the bubble being pushed into the reservoir, the fluid will flow under the air bubble if you are slow enough. Make sure it's pressurized before you open the bleed screw, so fluid is replenished immediately! (I used about 5 PSI, but you can probably use up to 10 or 15) On this car, it's really hard to see the internal structure that prioritizes hydraulic fluid availability to the brakes. On my E82, you could see it with a flashlight in the back - it's surprisingly small! The reservoir needs to be very full (overfilled, honestly), so that the fluid overcomes a little "dam" spillway inside the reservoir and allows flows of brake fluid to the master cyl instead of air. If you don't keep the reservoir continuously filled, air will get sucked into your master cylinder, and that sets you back quite a ways because now you need to bleed the upper portion of the system. Crack the bleed valve open, I did about 2 to 3 turns and let some fluid through. Close the valve, and now *slowly* start actuating the clutch - you don't want to suck air in, you want the pressure bleeder to supply fluid to the clutch portion of the reservoir. It will fall to the floor and not return - don't panic. Do this a couple of times, then crack the bleed valve open some more. I repeated this about 4 times and it started feeling pretty good.

Important note: DO NOT pump the clutch with the slave cylinder attached to the hydraulic line, but not installed in the bell-housing against the throw-out fork. Like others have experienced and described, you will cause the piston to overextend, blow the seal, and send brake fluid gushing everywhere like a balloon of brake fluid just popped. I suppose you could clamp the piston down it if you really wanted to do that, but to properly bleed, you need to pump the clutch pedal and manually lift it back up multiple times to cycle the piston. So you may as well properly install it before you mess with the hydraulics. I have not experienced this first hand, but in reading other threads, this was mentioned.

Also note: I removed the F87's stock slave clutch cylinder and it defaulted to max extension. The new part was shipped fully retracted, and wouldn't pull out by hand. I wasn't sure if there was a shipping "clip" that held the cylinder in it's fully retracted position, or if once filled with fluid and actuated, it would sheer of a small piece of plastic and operate as normal. I checked under the dust boot, nothing obvious. I was also unsure if it would mate up correctly to the clutch fork, being fully retracted. Thankfully they have a grease on the clutch fork which gets on the tip of the slave cylinder, that showed that the it was actually going to seat properly - it would mate up just fine. Because the cylinder is allowed to wobble about by a fair number of degrees, you don't want that missing the clutch fork and exploding inside your bell-housing. You need to drop the transmission to clean that up! I installed it as it was shipped to me, and it worked perfectly fine.

Do this mod. The CDV is making you look like you don't know how to drive a manual. The CDV ruins the whole MT experience. You know how to drive a manual, and you know how to not shock the drive line - that is, unless you want to

[i128]

So is the result of this mod really a day/night difference as everyone is making it seem?

What difference is most apparent?

-clutch feel?
-engament point?
-gear transition?

All the above?

[designatedposter]

Originally Posted by i128

So is the result of this mod really a day/night difference as everyone is making it seem?

What difference is most apparent?

-clutch feel?
-engament point?
-gear transition?

All the above?

I did it at the same time as upgrade to the 550i/335is clutch on my m235i. For me, not a night and day difference, however, my 1-2 shifts are better now, presumably due to more consistency. I don't do alot of fast shifts, so this mod is less significant for my driving style.

I'd say that if you are dissatisfied with your current setup, then it's worth a try, as long as you are up to the challenge of bleeding the clutch. A badly bled clutch would negate the benefits..

[bitcore]

I would say all of the above.
This "upgrade" makes it possible to drive the car smoothly, whereas previously it was nearly impossible to predict the correct engagement bite point. Judders and rough engagements were something I would fight against constantly. Now it feels "normal" and predictable, it's SO easy to drive smoothly now.

I did this mod for the low speed daily quality of life improvements it brings. I'm sure it's nice to have on the upshift as well, and when driving aggressively, but the improvements there are less noticeable because you are driving hard anyway.

On downshifts, it's also smoother. The auto-rev-matching is excellent after this mod and it's darn near perfect. I didn't think I would like the auto-rev-match when I stepped up from 135i to to the M2C, but it's actually quite nice now. I wasn't joking when my partner said it's smoother than an automatic, that's actually possible to achieve now. You'll actually be gaining clutch driving experience and perfecting technique instead of merely having to guess the engagement point and "hope" for a smooth engagement.

Imagine having a date, spouse, or friend in the passenger seat - someone who isn't a car nut like we are. You know that every once in a while when you pull away at normal civilian road speeds (when you're not trying to drive like a bat out of hell), you have a horrible launch and it's jerky. And then again, you do a normal or slower speed shift 1->2 to try and make up for it and be a smooth operator, but shifting slower makes it WORSE and the shift is again a bit of a rough one. Notice how that shakes your passenger and makes you not only look like you don't know how to drive the car, but it's an unpleasant experience and can trigger a lot of people's nausea. That issue is eliminated now, and I can shift perfectly, every time now (except when *I* screw it up). I experienced the same effect on my 135i after removing the valve - huge difference. I'm no longer fighting the machine, I'm working with the machine.

For 80 bucks, plus 10$ of BMW fluid and a few hours of your time if you have the tools - do it now. Or go to a shade tree mechanic for $120-200 for an hour of their time and have them swap it out. 100% worth it. If you are really cheap, you can remove the valve itself with a pick tool or a drywall screw and simply reinstall, but other reports of leaks exist. Perhaps remove the part, but drill it out and re-assemble is another option. I oped for the full E90 part. Plus if you are in warranty and have a driveline problem like a spun crank hub, you can re-install the OE part and reduce the chances of a warranty claim being denied because the CDV is missing. I'm absolutely certain that I'm causing LESS driveline shock now than with that stupid metered orifice "valve" in there. If you are able to drive it smoother: you are not beating up on all of the bushings, bearings, u-joints, flex disk and possibly even the clutch itself, and should therefore last longer because it won't be slipping as much and grabbing at unpredictable points on EVERY shift.


For me, I wanted a 6MT because I absolutely adore a driver-operated clutch. For those of us who share that love for the 3rd pedal, this mod is a must.

[FluffehPanda]

Never drove another manual BMW yet. How does the feeling compare to stock?

[rybski]

Originally Posted by bitcore

I would say all of the above.
This "upgrade" makes it possible to drive the car smoothly, whereas previously it was nearly impo....... share that love for the 3rd pedal, this mod is a must.

Hey all, So a year ago I did the "kern417" method and just removed the metal pinhole piece. I'm doing a 550i clutch upgrade at 43K (slippage w/BM3 stage2+ E30 tune) Should I go the E90 slave route while I'm doing the clutch???
Any difference in the E90 vs. CDV delete?

THANKS!

[kern417]

Originally Posted by rybski

Hey all, So a year ago I did the "kern417" method and just removed the metal pinhole piece. I'm doing a 550i clutch upgrade at 43K (slippage w/BM3 stage2+ E30 tune) Should I go the E90 slave route while I'm doing the clutch???
Any difference in the E90 vs. CDV delete?

THANKS!

There's no difference.

[oranga]

I just did this and had a few questions. After I initially swapped over the e90 cylinder, it leaked from the connection point. I ended up having to grab the little spacer from the f30 cylinder and putting it in the e90 one. This seemed to stop the leak. Is this what others have done?

[vrooooom]

This same part mentioned above is also good for the 2018 M2?

This CDV sounds like the slippage I feel when I’m on 2nd going to 3rd. Like 3rd won’t bite. Is that correct? I also find the 1st and 2nd gear rather hard to drive smoothly. Need to do this.

My M2 is overdue for a bleed also, thinking of doing the stainless braid as well at the same time.... do you guys think it's really noticeable?

[kern417]

Originally Posted by vrooooom

This same part mentioned above is also good for the 2018 M2?

This CDV sounds like the slippage I feel when I’m on 2nd going to 3rd. Like 3rd won’t bite. Is that correct? I also find the 1st and 2nd gear rather hard to drive smoothly. Need to do this.

My M2 is overdue for a bleed also, thinking of doing the stainless braid as well at the same time.... do you guys think it's really noticeable?

Yes it's the same. It will help with smoothing out the 1-2 shift. It's not guaranteed to prevent slip but if you're getting locked out of gear when trying to shift fast then it may help there too. I don't see the stainless line being a noticeable improvement.

[vrooooom]

Just some clarification.

For other BMW models, the CDV is just an added part that can be disconnected and discarded. Remove the CDV part/section, plug the line back in. But for the M2 it's built into the slave to which we have to either 1) buy a new one (easy route) or 2) use a pick/screw and pull the restricting pieces right off and risk leakage.

Did I get it right?

[celsdogg]

I finally did this swap. Its almost telepathic now. Just incredible.

Thanks Tchao!

[vrooooom]

Originally Posted by celsdogg

I finally did this swap. Its almost telepathic now. Just incredible.

Thanks Tchao!

So which process of bleeding did you do? How long did the whole thing take?