Bleeding the Z3M clutch slave

[Z3MROADY]

OP, in reading back, I see where you said your tool keeps from bottoming the piston. The piston HAS to be bottomed, or you're wasting your time with the tool.

I've modified the tool to compress the plunger so it bottoms out. I ordered what looks to be a good brake fluid recovery bottle (from Turner) and a also a small oiler to reverse bleed the system. This should allow me to do the job alone without a buddy to pump the pedal. I plan to give it another try this weekend and will report back, this time with good news I hope!

[MrDangles]

Do you put thick lube around the bleeder threads to try and prevent air from penetrating the threads?

i was planning on using a syringe with a line attached to it and forcing the fluid up into the reservoir.

[Z3MROADY]

I picked up a 60 oz. jet pump oiler at the hardware store for $6. It has a flexible tube that looks like it will fit tight over the bleeder to prevent air from entering when reverse bleeding. If it isn't tight enough it would be easy to insert a barbed adapter into the hose and add the proper sized tubing.

[gmushial]

Do you put thick lube around the bleeder threads to try and prevent air from penetrating the threads?

i was planning on using a syringe with a line attached to it and forcing the fluid up into the reservoir.

I just used a pump type oil can, with a piece of rubber hose crammed on the spout end, and the other end goes onto the bleeder nipple.... which means also that if necessary, I can take the top off the can, add more brake fluid to it, and then continue.

[Z3MROADY]

Well I'm sorry to report that after three hours this morning my clutch issue is no better. I removed the slave, compressed the plunger all the way in, reverse bled the system with the hose at the top and the bleeder pointing downward and to the rear, removed the tool and pressed the plunger in a dozen times, reinstalled, and still clutch engaged with pedal at the floor. I had a hard pedal with the tool on the slave after the reverse bleed so I was optimistic but when everything went back together the problem returned. I repeated the procedure 4 times and probably reverse bled about 4 oz. of DOT4 back up to the reservoir in all being very careful not to send any bubbles up the hose. Note: I have a new non braided 3.0 rubber hose. Could it be that this hose is expanding and I need the SS braided type hose? I'm out of ideas. Any thoughts other than going to the Dealer? I wonder if the slave itself is bad and the plunger is not extending out far enough. It isn't leaking. I saw a youtube video where the guy changing his BMW slave installed a replacement that had a longer plunger. Thx.

[Shoe Coupe]

subscribed, ive had the same exact problem with my shoe and no amount of bleeding, or anything else has fixed it. I too have the 3.0 line, i have the bav auto plunger tool. Ive gone as far as changing my clutch fork, divot, clip, throwout bearing (on a clutch job)..none of those helped. Ive bled up, down, sideways, you name it. No go.

love to get to the bottom of this.

[Z3MROADY]

subscribed, ive had the same exact problem with my shoe and no amount of bleeding, or anything else has fixed it. I too have the 3.0 line, i have the bav auto plunger tool. Ive gone as far as changing my clutch fork, divot, clip, throwout bearing (on a clutch job)..none of those helped. Ive bled up, down, sideways, you name it. No go.

love to get to the bottom of this.

I would as well. My wife had a very hard time getting into 2nd and yanked the shift knob right off the stick ( no, you do not want to mess with her .
Does anyone have a new stock M slave unit they can measure stroke of the plunger when at full extention?
I'm also starting to wonder about my master leaking internally per Randy' post. Hmmm.

[Shoe Coupe]

I would as well. My wife had a very hard time getting into 2nd and yanked the shift knob right off the stick ( no, you do not want to mess with her .
Does anyone have a new stock M slave unit they can measure stroke of the plunger when at full extention?
I'm also starting to wonder about my master leaking internally per Randy' post. Hmmm.

You brought up the master. Earlier randy mentioned dont EVER bring up the master.

Now prepare for your punishment beating.



- - - Updated - - -

It's not the master. Before you even go there, it's NOT the master.

QFP

[Z3MROADY]

You brought up the master. Earlier randy mentioned dont EVER bring up the master.

Now prepare for your punishment beating.



- - - Updated - - -

QFP

But in a later post he also said that a master can leak internally so it is a possibility (although remote). I can't assume any part in the system is working correctly at this point I guess.

[Shoe Coupe]

But in a later post he also said that a master can leak internally so it is a possibility (although remote). I can't assume any part in the system is working correctly at this point I guess.

with randy, you always prepare for a beating.






















<3 randy...dont hurt me.

[Z3MROADY]

with randy, you always prepare for a beating.

<3 randy...dont hurt me.

ShoeCoupe - When you had your slave plunger compressed all the way in (in the tool) do you recall if your clutch pedal was hard at the very top of travel or was there a little free play at the top before it firmed up. I have some play there that I may need to investigate.

[Shoe Coupe]

ShoeCoupe - When you had your slave plunger compressed all the way in (in the tool) do you recall if your clutch pedal was hard at the very top of travel or was there a little free play at the top before it firmed up. I have some play there that I may need to investigate.

So here's what happened to me. When I first did it, I had a ton of slop. Then i discovered that my clutch pedal was worn. Where the master cyl pin meets the plastic pedal, it had worn out. (see pic)....





So I replaced the pedal, and with the plunger pushed in, after bleeding it is solid... and just like you, when I put it back together, it engages low and shitty

110302-IMG_20110302_204457.jpg

[CoMZ302]

Didn't have any luck with slave plunger pushed in, or the master depressed. For me the master had to be full out, and the slave had to be installed in the bellhousing.

Advanced Auto sells a blue oil can that already has a hose and little metal tip on it. I cut off the tip, and it fit perfectly over the slave bleeder.

Opened the bleeder just a tiny little bit. I was surprised how long it took for the oil can to push enough fluid through the system to fill the reservoir. Then I realized that each pump was only about 2/3 of the length of the hose. Because the hose is clear, you can stop if you see air coming up the line before it gets to the bleeder valve.

HTH

[rf900rkw]

When a master fails, the fluid leaks out to either the ground or the reservoir over time. For the brakes, the pedal will slowly sink to the floor as the fluid bleeds out. For the clutch, you will have the pedal down, and the clutch will start engaging on it's own. A failed master can not make the pedal spongy but consistent. A bad master will bleed down.

[djb2]

When my e30 clutch master failed it initially would 'catch' at a random point in the travel, resulting in an unpredictable engagement point. (It did quickly fully fail, and the tear in the seal was easy to spot.)

[rf900rkw]

Okay, that is another failure mode, where the seal doesn't "umbrella out" under light pressure. And once it catches and seals, it stays sealed for that operation. A key word in there is "random". Nothing, then all. No squish. And it is often controllable by the speed of application. A squishy/spongy pedal that is consistent, or pumps up with quick successive applications, is air; not a failing master.

[gmushial]

Didn't have any luck with slave plunger pushed in, or the master depressed. For me the master had to be full out, and the slave had to be installed in the bellhousing.

Advanced Auto sells a blue oil can that already has a hose and little metal tip on it. I cut off the tip, and it fit perfectly over the slave bleeder.

Opened the bleeder just a tiny little bit. I was surprised how long it took for the oil can to push enough fluid through the system to fill the reservoir. Then I realized that each pump was only about 2/3 of the length of the hose. Because the hose is clear, you can stop if you see air coming up the line before it gets to the bleeder valve.

HTH

Sounds approx. what I created and worked... though didn't have the luxury of a clear hose in that I used black vacuum line... and yes, took quite a while to pump the new fluid up into the res... I used a turkey baster to pull excess out of the res, and used new clear fluid coming up from the bottom as an indicator [the brake fluid wasn't that old, but was already a slightly different color than the new]. And likewise: don't think the master can be depressed any, in that will cover the ports and not allow for the flow of fluid.

[Z3MROADY]

My clutch pedal stays rock hard when the slave is bled and in the tool so the master must be ok. Assembled the pedal operates smooth and does not feel spongy. Nothing changes as I pump it repeatedly. Engagement stays at the floor. Note: I checked with ECS and they said that all of the varios slaves they sell for the Z3M have the same plunger dimensions I was hoping there was a compatible slave with a slightly longer stroke.

[rf900rkw]

The actual pushrod has nothing to do with the stroke. What you need is a smaller bore slave cylinder. It just so happens one exists. E36 325i. Stock is 7/8" bore, the 325i is 13/16", roughly 15% longer stroke.

[Z3MROADY]

The actual pushrod has nothing to do with the stroke. What you need is a smaller bore slave cylinder. It just so happens one exists. E36 325i. Stock is 7/8" bore, the 325i is 13/16", roughly 15% longer stroke.

Now we're talkin' That's awesome!
I'm going to order one right now and give it a try. Does it matter which year?
Real OEM lists the part# as 21521161530. (D=20,64mm/GG)
Looks like it is superceded by 21521159045 (92 - 95 325i)
Thanks Randy!

[Shoe Coupe]

isnt that going to make the clutch significantly heavier?

[rf900rkw]

Some have the ports in different spots. A little creativity or a UUC braided line will get the job done.

[Z3MROADY]

isnt that going to make the clutch significantly heavier?

I'm about to find out.

[rf900rkw]

15% quicker, 15% more effort. Not recommended for a Stage 2 or higher pressure plates. I run the 325 slave on my stock S52s.

[gmushial]

This should go into the FAQ threads :-)