Bleeding the Z3M clutch slave

[rf900rkw]

It is. Several times. It's been brought up in previous threads.


one thing that will make the clutch release right on the floor and defy all attempts at bleeding. The nylon release arm pivot can wear down.

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I've taken them out where they look like new, except color. I've taken them out worn down to a flat disc. Replace it every time you have the trans out. Use the factory nylon piece, don't get a brass one. The bellhousing is a dirty abrasive environment; the self lubricating plastic lasts longer.

[Z3MROADY]

I just finished installing the new 325i slave (and UUC clutch line) and WOW...WOW...WOW! Shifts like new. No notchiness, engagement is about 1-1/2" from the floor. The pedal is a touch "heavier" but that's OK by me. I though my prior pedal was too soft. Now great shifts up and down. Like butter.
Here's a photo of the 325i and Z3M slaves side by side. Note the longer plunger on the 325i. It installed and reverse bled no problem. Man, am I a happy camper now! I have a few more pics that I could post up if anyone is interested. Thanks all!

UPDATE: 8/5/22 The 325i CLUTCH SLAVE that I installed in my '98 Z3MR is still performing perfectly. Buttery smooth shift from N thru all gears up and down No issues!

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[rf900rkw]

Glad it worked out. But for future searches it is not the length of the pushrod that made the difference. It is the bore diameter coupled with your now-expert bleeding procedure. The slave piston floats to whatever position it needs to in order to maintain contact with the release arm. A longer pushrod just means the piston starts off that much farther back in the bore. It will still move forward exactly the same amount; determined by the volume of fluid coming from the master. As long as you stay within the mechanical limitations.



Place an object on the floor. Using a 3 foot long rod, push the object forward exactly one foot. The object moved a foot, correct? Now put the object back to where it was, and this time use a four foot rod to push it one foot. It again moved one foot. From the object's perspective nothing changed. It got shoved from here to there. As long as you choose a rod length that will fit in the room, the one foot of travel will be one foot of travel. Same with the slave cylinder. As long as the rod isn't so long that it bottoms the piston in the bore, the effective stroke at the tip will be the same for different lengths.

[Z3MROADY]

Thank you for that detailed explanation (that makes perfect sense) and also for the recommendation to try the 325i slave in the first place. Now I'm off to take a little drive and pick up some champagne to celebrate

[Shoe Coupe]

hmmmm. maybe i should do the same....

[Z3MROADY]

hmmmm. maybe i should do the same....

After I gathered all the tools and supplies it took me 2 hours start to finish by myself. If you reuse your 3.0 line you can probably improve on that time a little bit. Time well spent IMHO. I had a pit to work in so access was good. If you go with the UUC hose make sure it is properly aligned with the slave inlet (and the slave is mounted) before tightening the UUC hose to master hose connection.


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Also remember to remove your temporary clamp on the resourvoir hose before reverse bleeding (doh!) Two items that slowed me down

[Shoe Coupe]

So I have the oem 3.0 z3 line, I've bled it forwards, backwards, on and off the car with the tool. Nothing helps


I put my gopro under the car and hit the pedal and this is what I found. This line doesn't have very many miles on it, but I don't think it should be flexing this much... I also held the line while my friend pumped the pedal and you can feel the line shrinking and twisting before it does any work .

Does it look like a defective line?

The first 1/4 of travel in my pedal is just squishy, and I definitely don't have air in the system


Here is the video, excuse my announcements. It was for my own info. I didn't even call it out right lol

https://youtu.be/y_3kAY1Hhk4

[gmushial]

So I have the oem 3.0 z3 line, I've bled it forwards, backwards, on and off the car with the tool. Nothing helps


I put my gopro under the car and hit the pedal and this is what I found. This line doesn't have very many miles on it, but I don't think it should be flexing this much... I also held the line while my friend pumped the pedal and you can feel the line shrinking and twisting before it does any work .

Does it look like a defective line?

The first 1/4 of travel in my pedal is just squishy, and I definitely don't have air in the system


Here is the video, excuse my announcements. It was for my own info. I didn't even call it out right lol

https://youtu.be/y_3kAY1Hhk4

When I did this dance 2ish years ago, the hose looked perfect... but what was happening was it had delaminated internally, so that fluid from the master was going between the two layers and pinching off the main channel within the hose.. though a little was getting by but the clutch action really sucked... I replaced it with (an initially defective) UUC braided line and that was the solution. [the defective was a burr in the threads on the master cyl end that kept it form threading... but after a half hr of fighting with it, I pulled it and visually checked and it was obvious why it wasn't threading - seems a bunch of others have had the same problem - but by unrolling the crushed thread, it went on the first try.... bottom line: check threads before trying to install.]

[Z3MROADY]

So I have the oem 3.0 z3 line, I've bled it forwards, backwards, on and off the car with the tool. Nothing helps

I put my gopro under the car and hit the pedal and this is what I found. This line doesn't have very many miles on it, but I don't think it should be flexing this much... I also held the line while my friend pumped the pedal and you can feel the line shrinking and twisting before it does any work .

Does it look like a defective line?

The first 1/4 of travel in my pedal is just squishy, and I definitely don't have air in the system

Here is the video, excuse my announcements. It was for my own info. I didn't even call it out right lol

https://youtu.be/y_3kAY1Hhk4

My 3.0 line was behaving about the same way. It was new with less than 200 miles on it. I would expect a flexible hose to move a little as the pressure builds. Especially if there is any twist in it after assembly. I too had a small amount of pedal travel at the top before it seemed to start acting on the clutch lever. Not squishy just easy travel before there was noticeable spring back pressure. Now with the new 325i slave and UUC line the point of engagement is where I think it should be. I'm curious though how it would feel if I left the 3.0 hose in there. Oh well not going back to that now.

[Shoe Coupe]

My 3.0 line was behaving about the same way. It was new with less than 200 miles on it. I would expect a flexible hose to move a little as the pressure builds. Especially if there is any twist in it after assembly. I too had a small amount of pedal travel at the top before it seemed to start acting on the clutch lever. Not squishy just easy travel before there was noticeable spring back pressure. Now with the new 325i slave and UUC line the point of engagement is where I think it should be. I'm curious though how it would feel if I left the 3.0 hose in there. Oh well not going back to that now.

im going to try another z3 hose...it's cheap and relatively easy to replace

[Z3MROADY]

im going to try another z3 hose...it's cheap and relatively easy to replace

Good luck. Report back with your results.

[Shoe Coupe]

Good luck. Report back with your results.

thanks! I want to see what randy has to say about the hose flex...

[rf900rkw]

That's fairly common. The hose has a bit of a twist in it as installed, and tries to straighten itself under pressure. It is lost motion, but shouldn't be enough to really hurt, unless there are other things compounding.

[Venom13132]

I had an externally leaking master cylinder when I got the car (drove it 800 miles home with it leaking). It really made for some notchy shifting. I replaced the MC. I had a steel braided clutch line but did not realize it replaced the small hard line also so I didn't see how it fit and have not installed it yet. But I got the Master Cylinder done and used a big syringe and some rubber tubing I got on amazon (can post links to what I purchased if anyone would like). Then I filled the syringe with new brake fluid and filled the tube and pushed the air out as best I could before attaching it to the bleeder on the slave and reverse filling the system. I gave the clutch pedal a few good pumps. I let it set for a few days. And it works great. The clutch engages maybe 1/2 an inch off the floor instead of on the floor and the car shifts better. I had to get the car running for an event this weekend so I didn't have time to replace the clutch line. I will do that when I get back. Interested in swapping in the 325i e36 MC to see if I can raise the clutch engagement point a bit like I read Z3MRoady did.

[Z3MROADY]

....... Interested in swapping in the 325i e36 MC to see if I can raise the clutch engagement point a bit like I read Z3MRoady did.

Just to be clear, I only swapped in the 325i Slave unit. My Master is still the original ///M unit.

[Venom13132]

Just to be clear, I only swapped in the 325i Slave unit. My Master is still the original ///M unit.

yeah, I got that! I already swapped my leaky master with an OEM one. But I like the idea of having the engagement point a little higher like you said yours was.

[Shoe Coupe]

So just finished my clutch line adventure...

Basically the original Z3 3.0 line i installed was bad. It had ALOT of give to it and didnt resist twisting near as good as the replacement Z3 3.0 line that I got.

Of course, I went to replace the line and do a brake bleed on my m3, and for the second $@%@ing time my bav auto branded power bleeder split at the filler neck where the pump meets the flange that sits on the bottle. DO NOT BUY THEIR CRAPPY OVERPRICED BLEEDERS! Even the warranty unit with an updated design split and wont hold air. Had it with them.

So we did a manual bleed, as I was lucky my neighbor was around and helped me pump the pedal. We got a ton of air out. Now my clutch pedal is no longer squishy and has pretty good feel. The clutch engagement point is a bit higher than before but overall low, probably an inch to inch and a half off the floor, but all the slop is gone.


And for the record, this line has ZERO twisting in this line, like at all. its straight as an arrow, even with the pedal all the way down. The old line not only twisted but it shrunk when the pedal went all the way down. I think that alone is responsible for 90% of the slop i had before.


Happy with my clutch engagement now, not quite as good as my e46 m3, but comparable.


One other observation....even basic z3 parts are getting hard to find. I had to look all around town for a z3 line. My brother's in the auto parts business, and even with his multiple whole sale distributors, most only had the hose special order. Only one of the largest had ONE and it was out of the way. Kind of sad.

[gmushial]

So just finished my clutch line adventure...

Basically the original Z3 3.0 line i installed was bad. It had ALOT of give to it and didnt resist twisting near as good as the replacement Z3 3.0 line that I got.

Of course, I went to replace the line and do a brake bleed on my m3, and for the second $@%@ing time my bav auto branded power bleeder split at the filler neck where the pump meets the flange that sits on the bottle. DO NOT BUY THEIR CRAPPY OVERPRICED BLEEDERS! Even the warranty unit with an updated design split and wont hold air. Had it with them.

So we did a manual bleed, as I was lucky my neighbor was around and helped me pump the pedal. We got a ton of air out. Now my clutch pedal is no longer squishy and has pretty good feel. The clutch engagement point is a bit higher than before but overall low, probably an inch to inch and a half off the floor, but all the slop is gone.


And for the record, this line has ZERO twisting in this line, like at all. its straight as an arrow, even with the pedal all the way down. The old line not only twisted but it shrunk when the pedal went all the way down. I think that alone is responsible for 90% of the slop i had before.


Happy with my clutch engagement now, not quite as good as my e46 m3, but comparable.


One other observation....even basic z3 parts are getting hard to find. I had to look all around town for a z3 line. My brother's in the auto parts business, and even with his multiple whole sale distributors, most only had the hose special order. Only one of the largest had ONE and it was out of the way. Kind of sad.

What was the brand of the bad hose? Or was it a standard bimmer item, and it just was badly done?

W/re parts going away: yup... the early Z3s will be 20 years old this year - in some circles that's considered a classic car. But equally, that's why I got my front rotors for a song: they'd been sitting on the parts store shelf for quite a while, the owner didn't see them being sold anytime soon, so he was happy to let me have them for his cost, just so that he could be whole again w/re to them. One also sees this in the RealOEM listings, where the original parts have been crossed to a more recent part - sometimes the same critter, just a new number; sometimes a different part, that will happen to work.

[rf900rkw]

When I call my BMW dealer for some obscure part, I sometimes get told it has to come from Germany, be here in a week. When I call the Chevy dealer for a common part for my '97 S10, they about choke trying to get out "NLA" between the fits of laughter. As far as 20 year old cars go, we have it most excellent.

[Shoe Coupe]

When I call my BMW dealer for some obscure part, I sometimes get told it has to come from Germany, be here in a week. When I call the Chevy dealer for a common part for my '97 S10, they about choke trying to get out "NLA" between the fits of laughter. As far as 20 year old cars go, we have it most excellent.

I doubt doubt it. Considering my 6 year old infiniti, if you break a bushing, you have to buy an entire subframe.

My point was I'm bummed a parts are becoming more scarce.


As far as the hose, it was standard issue BMW. I think the hose is FTE. I'll post a picture of it out of the car. It looks like a pig's tail

[gmushial]

It used to be that for aircooled VWs one could get parts down to the single screw - but when Mexico stopped making them, then availability went to hell in a handbasket, and especially for the Type III's the situation got real bad real quick... now other than Type I's parts are basically gone.

Currently I think the most available parts I find are for the Corolla and Camry Toyotas, even for the old ones I never run into a NLA. W/re Randy's comment: I think the ///M people have it a lot worse than the non-///M Z's, even then parts are starting to NLA.... but given the choice btwn a "modern" car and an older one that is lovable: I keep wavering between a ND MX5, an Elise and another Z3... this week it's the Z3.

[bubbafett]

I just did this a couple weeks ago. I uses a OE slave and a UUC line, with the bevauto tool and motive power bleeder. I took me a couple tries to get the air out. I used the instructions from post http://www.bimmerforums.com/forum/showthread.php?2128364-So-I-replaced-my-M-roadster-clutch-line-today&p=27938021#post27938021

and https://www.bavauto.com/Assets/inst_pages/ins325.pdf

A couple things from my experience what finally worked for me was , when the plunger is compressed using the bevauto tool, when under pressure with the power bleeder, then opening the bleeder up, then I pushed the clutch petal to the floor by hand maybe 10 or 12 times, finally changing orientation of the slave from horizontal to vertical and jiggling it (vibrating it by hand). This then yielded allot of air out into the bleeder tube catch bottle. As Randy has said before if your clutch petal is not rock solid then you still have air...

[Z3MROADY]

My pedal was always rock solid but had very low engagement (at the floor). For me the trick was to go to the other slave. Pedal still feels great now.

[rf900rkw]

I changed out the clutch master cylinder in the roadie a few weeks back because I shattered the pushrod eyelet. No helper, no pressure bleeder, no slave holder; never touched the slave. The clutch releases a good two inches from the floor.

[jbrannon7]

I guess I am extremely fortunate. Mine bleeds all by itself. I just have to make sure the reservoir is filled and pump the pedal a dozen times and it is ready to go.