Slave cyl/clutch issues/noise w/video

E28 technical advice asked and given! Troubleshooting, modifications and more.
Post Reply
Capt.GourddelFunK
Posts: 73
Joined: Jun 07, 2013 9:15 PM
Location: Charlotte, NC

Slave cyl/clutch issues/noise w/video

Post by Capt.GourddelFunK »

Hate to make a new thread on something covered in depth, but just can’t figure this out. Moving at the end of the month so starting to get a bit stressed.
Slave cylinder was leaking on the floor, went to replace. Replaced and bled via pushing in push rod with slave uninstalled. Replaced the clutch master maybe 4-5k miles ago (4 years) and bled this way with no issues. Go to check pedal and have no pedal. Pump several times and get less than half pedal but heavy resistance and this very loud squeak from under the car (slave/trans area-video linked below) that has never happened. Took the slave out and the pushrod was basically disconnected, wobbly, no leaks though. Read stories of rod falling in bellhousing so had FCP send me a new one.
This time I installed the new one (rod on this one seemed a little wobbly out of the box, more so than the original I pulled from the car), bled the same way, no pedal at all. Would occasionally get an inch of pedal, then collapse to the floor again (I have clutch pedal spring deleted).
Open bleed screw and drain until no more fluid, then reverse bleed from bleeder screw via oil can. Worked and when no more would flow it coincided with just below max level on reservoir. Still no pedal.
Take out slave and try the hand pump bleed again. Pushrod is wobbly again like the other one, more so than out of the box. But I bleed anyway and do notice I can push the pushrod in pretty easily without bleed screw cracked. Reinstall. Get exact same symptoms as first time: less than half pedal, very resistant, very loud squeak. It did go all the way to the floor once but next pump went back to same condition.
Anyone have experience with this loud squeak and resistance? I ordered a clutch master and having fcp send another slave but trying to troubleshoot. Have bled the clutch several times before and never had this issue nor the noise.
As always thanks for any help.

Video of noise: https://vimeo.com/720496625
Shawn D.
Beamter
Beamter
Posts: 21991
Joined: Feb 12, 2006 12:00 PM
Location: Alpharetta, GA
Contact:

Re: Slave cyl/clutch issues/noise w/video

Post by Shawn D. »

That's a strange one. I wonder if the other end of the arm that works the throwout bearing has come off the pin, or the pin itself has broken.
Capt.GourddelFunK
Posts: 73
Joined: Jun 07, 2013 9:15 PM
Location: Charlotte, NC

Re: Slave cyl/clutch issues/noise w/video

Post by Capt.GourddelFunK »

What an exciting prospect…
I’ve got very little transmission experience admittedly. After all this the second time I did feel inside the hole for the pushrod and the piece that the pushrod engages did press back without much resistance, moved it easily with my finger, almost felt a little floaty but balanced and returned to position when I withdrew my finger…is that normal behavior?
Shawn D.
Beamter
Beamter
Posts: 21991
Joined: Feb 12, 2006 12:00 PM
Location: Alpharetta, GA
Contact:

Re: Slave cyl/clutch issues/noise w/video

Post by Shawn D. »

I can't really tell what's going on based on your description. Do you have a Bentley and/or have you looked at the parts diagram on RealOEM.com?
Capt.GourddelFunK
Posts: 73
Joined: Jun 07, 2013 9:15 PM
Location: Charlotte, NC

Re: Slave cyl/clutch issues/noise w/video

Post by Capt.GourddelFunK »

Yea I do, have intermediate e28 repair experience, and have done the master and slave cylinders before, but don’t know the transmission at all. So unsure what part the slave pushrod engages inside the bellhousing. Thats what I was describing in my previous post.
I messed with it more today and seems to squeak less and I can get into gear, so perhaps pin/clutch arm situation is ok? I haven’t taken it off jack stands and tried driving with this current condition.
My plan as of now is to put the original one back in despite its leaking seal and see what behavior I get.
Mike W.
Posts: 26872
Joined: Feb 12, 2006 12:00 PM
Location: California Whine Country

Re: Slave cyl/clutch issues/noise w/video

Post by Mike W. »

Putting in the previous one isn't a bad first step, although I wouldn't hold my breath in hopes.

You didn't mention what E28 you had, and it makes a difference, as eta's had the lightest clutch, followed by 533s, followed by 535s, with M5s being the stiffest. Where I'm going with all this, is while the symptoms don't exactly match, I'd be tempted to replace/reinforce the pedal bracket as it's a known problem, although not exactly your symptoms. But it's an easy afternoon job.

I did finally watch/listen to the video and it wasn't really telling. But from your description, my guess is it's in the bellhousing and will require pulling the tranny. Which is real work. Actually the tranny itself isn't that bad, but you've got to pull the exhaust and driveshaft first which turns the entire ordeal into a weekend job, at least for me to R and R everything. And I've done a bunch. (pros with a hoist and a helper to shoulder it out of there at shoulder level don't count)

There's a pivot pin which I would suspect to be the culprit. It's #5 in the illustration and the release lever, #3 pivots against it, with the clutch slave pushrod pushing against the other end of #3. https://www.realoem.com/bmw/enUS/showpa ... Id=21_0017

So... if it was me... I'd go back to the previous slave cylinder. No luck? Then I'd do the pedal bracket. No? Then I'd pull the tranny. At least from here, many electrons away from hands on.
Capt.GourddelFunK
Posts: 73
Joined: Jun 07, 2013 9:15 PM
Location: Charlotte, NC

Re: Slave cyl/clutch issues/noise w/video

Post by Capt.GourddelFunK »

Thanks for the response Mike. I have already replaced pedal bracket and reinforced with aftermarket part, did that same time I did the master cylinder a few thousand miles ago.
And it’s a 535is…would the arm/fork, number 3 in that diagram, feel very light and floaty if I pressed it with my finger? It returns to position without any problem. And as mentioned above, I can shift into gear pretty easily…would it shift if that arm was off the pivot pin/pivot pin broken?
Preciate the help
Mike W.
Posts: 26872
Joined: Feb 12, 2006 12:00 PM
Location: California Whine Country

Re: Slave cyl/clutch issues/noise w/video

Post by Mike W. »

Capt.GourddelFunK wrote: Jun 19, 2022 8:21 AM Thanks for the response Mike. I have already replaced pedal bracket and reinforced with aftermarket part, did that same time I did the master cylinder a few thousand miles ago.
Good, one less thing to worry about.
And it’s a 535is…would the arm/fork, number 3 in that diagram, feel very light and floaty if I pressed it with my finger? It returns to position without any problem.
Yes, but it probably would without the slave in place and bled. The lever arm is held in place at the pin side by a very light duty spring, which might continue to hold it even if the pin were broken or damaged. The whole thing is kind of held in place by everything being in place, the TO bearing slides (or should) easily on the input shaft collar, there's a large cutout in the release lever the TO bearing goes into, it's actually a little surprising everything is as tight as it is once everything is in place.
And as mentioned above, I can shift into gear pretty easily…would it shift if that arm was off the pivot pin/pivot pin broken?
Preciate the help
It might, but you would probably have more travel on the clutch pedal before the clutch released, but it is a self adjusting clutch too. You might use a mechanics stethoscope, either a good one or a long screwdriver to your ear to make sure the sound is coming from inside the bellhousing. Unlikely, but it's even possible it's coming from the TO bearing or the pressure plate. It's obviously hard to make any definitive diagnosis without pulling the tranny, if the sound is indeed coming from inside. Some work, but you might consider pulling the mounting stiffener, #15 in the diagram to see if anything falls out or what it sounds like with less shielding around everything. https://www.realoem.com/bmw/enUS/showpa ... Id=11_0100
Post Reply