E36 Clutch Problem- Need Opinions

For the first time in many years, I'm a whits end with a car project, and am pondering actually taking a vehicle to a shop.  

A bit of back-story.  '96 E36 lost the clutch after start finish at Daytona in October (dual mass flywheel had lots of slop, and the disc had started to separate) .  Since I have an S52 sitting in the shop, figured it would be a good time to just go ahead and engine swap the high mileage but super reliable M52 out.  I've done a couple of E36 swaps in the past, never had any problems.  Dropped the engine / tranny, put new detents in the tranny, VANOS kit, etc.  The typical while it's out stuff.  Went back in without too much trouble, started right up with the M52 DME, while I figure out what I want to do for tuning.

Okay, so have running engine try to slip it into gear......nada, nothing.......so I pull the tranny and see if I can find anything wrong.  Nothing stands out....so replace master and slave.....reinstall.....nada.

So far:  New OEM slave, master and SS flex hose, new clutch fork, SS pivot pin, new TOB, I've pressure bled, gravity bled, stroked the slave off the tranny.  The ZF does feel more notchy with the engine not running, but I'm assuming thats the fresh detent kit.  I can slip it into gear with the engine running on the 2 post, but I can't force it to slip with the engine running so I don't think it's close to releasing.  You can see me trying to get it to slip in the video link below and the engine stalling.

Clutch kit is a lightly used JBR kit off another running track car.  I've been in touch with JBR (quite helpful) and they are adamant that the parts I have should work together correctly.  They are also adamant that the disc goes in backwards from typical E36 install, with the spring hub extension facing the flywheel.

I put a small inspection hole in the bellhousing so I could get a boroscope in there

https://youtu.be/X0oWo07siCI

It's clearly moving the TOB, but I'm guessing I'm getting 6-7mm of movement.  JBR thinks I need about 11 mm for the pressure plate to release correctly.

There are some good wrenches on this board, so hopefully someone will see something I don't.  I'm going to give it one more shot at bleeding it, and then I'm having it towed to a shop.

Thanks!

Glenn

The pivot pin screws in, right? Any chance it's screwed in too far (or somehow not tall enough)?

Robbie (Forum Supporter) said:

The pivot pin screws in, right? Any chance it's screwed in too far (or somehow not tall enough)?

I've thought about that as I'm running out of other things to check.  The fork pivot pin just drops into place. The SS pin was from a reputable supplier, BimmerWorld.  However, it did just drop in, I was expecting to have to give it a bit of a tap to get it to seat.  All the pics I've seen show the pin set all the way without a gap between the pin base and the tranny.  Thanks for the response!

This is screaming not bled to me.  Yes, I see that you bled it.  I'm wondering if there is somehow still air trapped in the system.

Or, alternately, is the pushrod for the clutch slave adjustable?  If it is, make it as long as possible and see if the clutch releases then.

wvumtnbkr said:

This is screaming not bled to me.  Yes, I see that you bled it.  I'm wondering if there is somehow still air trapped in the system.

 

Or, alternately, is the pushrod for the clutch slave adjustable?  If it is, make it as long as possible and see if the clutch releases then.

It screams that to me as me as well, I will go at it again today.  I'm using a motive pressure bleeder.  I also did the old fashion gravity bleed.  I will requisition the kid or wife to 2 person bleed it tonight.  

The slave rod isn't adjustable but I did see that Rogue makes an adjustable push-rod.  From 85-95mm length. I think stock is 90mm, so it would give you another 2mm ish at the TOB. That's assuming it's a length issue and not a force issue.  The stock push rod is almost completely back in the slave according to the boroscope photos. If I'm getting 6mm movement, that would mean I'm only getting about 12mm movement at the rod.  That doesn't seem like very much, given the 90mm length.

Get a mittyvac or a big syringe. Hook it to the slave bleeder, and try pushing fluid up that way. Might have to leave the slave hanging so that the bleeder is now at the "bottom".

That was the only way we got the AMC challenge car correctly bled. And we tried a lot of stuff.

I agree with everyone else that may need to bled again. Did you replace the flywheel?

What is your bleeding process? Did you leave the slave off of the transmission with the nipple facing the sky to bleed, then reattach?  We could not get our E36 bled without doing that, even with a pressure bleeder (we tried).  It's no fun, but it was the only way we could get it done.

Matt B (fs) said:

What is your bleeding process? Did you leave the slave off of the transmission with the nipple facing the sky to bleed, then reattach?  We could not get our E36 bled without doing that, even with a pressure bleeder (we tried).  It's no fun, but it was the only way we could get it done.

I have not tried pressure bleeding with the slave off. I was worried about the pressure ejecting the interior piston.  I know they make a speciality tool to constrain the rod when pressuring the slave off the tranny. I have pulled the slave, pointed the nipple up, and stroked the slave (opening bleed on the compression, closing on the release).  I'm sure I can fab up a quick bracket, and a couple of bolts to prevent that.

Strike_Zero said:

I agree with everyone else that may need to bled again. Did you replace the flywheel?

Came with the used clutch kit.  It was a JBR aluminum flywheel.  They've been helpful so far in troubleshooting and are pretty convincing that the parts I have "should" work fine.

wake74 said:

Matt B (fs) said:

What is your bleeding process? Did you leave the slave off of the transmission with the nipple facing the sky to bleed, then reattach?  We could not get our E36 bled without doing that, even with a pressure bleeder (we tried).  It's no fun, but it was the only way we could get it done.

I have not tried pressure bleeding with the slave off. I was worried about the pressure ejecting the interior piston.  I know they make a speciality tool to constrain the rod when pressuring the slave off the tranny. I have pulled the slave, pointed the nipple up, and stroked the slave (opening bleed on the compression, closing on the release).  I'm sure I can fab up a quick bracket, and a couple of bolts to prevent that.

I wasn't recommending using the pressure bleeder with the slave off (for the same reason you mentioned). Sorry if the way I wrote that was confusing. I just meant we couldn't get it to bleed with the slave attached, even with a pressure bleeder.  Sounds like you're already using the correct method.

wake74 said:

Strike_Zero said:

I agree with everyone else that may need to bled again. Did you replace the flywheel?

Came with the used clutch kit.  It was a JBR aluminum flywheel.  They've been helpful so far in troubleshooting and are pretty convincing that the parts I have "should" work fine.

Ok coolio. I was just checking.

Sounds like a 2-person job is order.

So, I slipped out (well I haven't left my home office in a year, so I'm not sure I'd call it slipping out), and bled the clutch some more.  Took the slave off, attached a piece of small channel to hold the piston, and pressure bled it with the nipple up.  Bled another 1/4 liter or so.  No sign of bubbles, microbubbles, etc. Reassemble.  Clutch feels fantastic, quite stiff.  Has pressure all the way to the floor.  I have  not tried backwards bleeding it yet, waiting on a turkey baster (wife was a hard no, on the Pampered Chef one) so I can suck out the reservoir.  

But, and it's a big BUT, damn thing still won't go into gear.  I'm beginning to think there is either a tranny /  problem, or something functionally wrong with the pressure plate, disc, flywheel stackup. 

Video of slave travel:

https://youtu.be/cPHN4ah18tw

Video of TOB travel:

https://youtu.be/5v2neF_SDvc

You say you purchased a new master and slave. You need to measure the bore in both and confirm that they are the correct size. I have seen far too many mis-labeled parts. Things that got into the wrong box somewhere in the supply chain. Too big a slave, or too small a master will get you here. If they are correct check as well the condition of the pedal brackets and pushrod clevis hole in the pedal. 

Maybe I missed it but I'm assuming it won't go into gear with the engine running right? Can you select gears with the engine off? Dumb question but I have to start at the top. 

spandak said:

Maybe I missed it but I'm assuming it won't go into gear with the engine running right? Can you select gears with the engine off? Dumb question but I have to start at the top. 

It will go into gear without the engine running, but it's pretty "notchy".  "Notchier" than I remember it, but I also swapped in new detent springs, so I would explain a little more resistance.  I can even change gears with the engine running on a lift, but of course it takes a bit of pressure to slip from one gear to the next with no clutch.

I'm running out of thoughts, other than maybe a defective pressure plate that is not releasing all the way around.  Or there is something messed up inside the tranny.  But I would think that would prevent me from getting into gear at all, or I'd hear odd sounds emitting from broken parts / pieces.  An E36 shifter isn't very complicated, not too many ways to install it incorrectly.

From your description, it does sound like a possible parts mismatch as alluded to by TurnerX19. BMW changed master cylinders at least three times during the E36 run. They supposed to work with the slave cylinder that was used the entire chassis run.

You can jump on RealOEM to look up part numbers for cross reference.

Just a thought . . .

See if you can rig up a C-clamp to push the clutch arm the required distance. If you can change gears, that would rule out issues with the trans, PP, and clutch.

 

Interesting my research shows that there were two different slave cyclinders in E36 models, with different bores.  The M3 had the larger of the two bores if I recall correctly.  Those were interchangeable from a physical dimensions I believe. The different E36 clutch masters were much different shapes, one has a very long extension that the hard pressure line clips to, the other a short one, they would not be interchangeable. I've got the long nose one.

Interesting thought on the rigging up a "manual" slave push rod.  I could fab up a small bracket bolted to the studs that hold the slave with a tapped hole and threaded rod that would "fake" where the slave normally sits that I could manually force the fork in, some additional distance.

I really like that line of thinking.  At least I could see if more travel would get it to release.  That would rule out hydraulics, slave travel, etc.

JBR continues to be very supportive, looking at videos, and has offered to inspect the flywheel, pressure plate,  and disc if I ship it back to them.  Great customer support considering I didn't even buy the parts directly from them.

The other option is to just set the whole thing on fire in the driveway, but that would no doubt result in an HOA fine, which would only cost me more money :-)

Thanks for the continued brain storming!  

My clutch clutches!!!!

After calling it bad names, threatening to burn it, I finally got the clutch to do it's job after a couple of  weekend of flaying away.  On a positive, I can drop a tranny pretty quickly, and I know exactly the best combination of extensions to pull an E36 slave.

After the comment from Strike Zero above, I fabbed up a way to manually depress the fork.  Okay, some left over metal, 3 holes, and a tap, are not really anyones definition of fabrication, but it served the purpose (I know some of you would have milled it out of aircraft aluminum).  It showed me that with enough push rod movement, the clutch would release and the tranny would shift fine. 

So with that revelation, I dug out the adjustable slave rod I just bought, just in case that would help, added 4 or 5 mm of length, and now it releases.   With the new exhaust it isn't exactly test drive in neighborhood friendly, but it has moved on its own for the first time in months. 

And a picture of the offender in question.  Thanks again for the brainstorming!

Awesome - congrats on your victory-over-stupid-metal-things! 

In reply to wake74 :

Strong work!

Well, my clutch saga continues.  First much needed track weekend of the year at CMP, signed up for Friday CMP day as a shakedown before the 2 day NASA weekend.  The first session, was just a touring lap / track familiarity session, much clutch slippage.  Didn't even bother to do a second lap.  Back in paddock shortened the adjustable push rod slightly, and reinstalled.  That's at best a crap job on your back in the dirt on jack stands with a hot exhaust.  First actual session, still slipping, so still not one lap.  Fought with it a few more hours on my back and was going to shorten the rod some more, but couldn't get the damn thing back on while on my back, and was getting more and more frustrated.  So, winched it into the trailer, said some not nice words, and returned home after 2 (very expensive) partial laps.

So back to the house and my lift.  An E36 pushrod is 88 mm long.  With the stock 88 mm push rod, the car will not go into gear.  With the adjustable pushrod about 90 mm long, the car shifts fine.  However, in order to install the slave with that extra 2 mm, I have to apply a bit of force to the slave with a lever as I can't push it hard enough to start the nuts. I'm guessing I'm bottoming the pushrod / piston into the end of the slave with the TOB pushed all the way into the pressure plate. So I'm preloading the TOB which obviously isn't good.

So as a recap:

- New slaves (I've tried both M and non-M) versions.  New Master.

- Bled 8 ways to Sunday, and have put many liters through it over the last couple of months.  I've done the 2 person, pressure with Motive bleeder, the "official Bentley" method locking the pushrod all the way in, stroked the slave with the nipple up etc. Clutch "feels" fantastic.  I'm getting decent movement out of the pushrod and TOB.  I cut a small inspection hole in the bellhousing for boroscope.

- New flex hose

- No CDV

- Used (but visually looked good) JB Racing flywheel set-up, with disc installed in correct orientation. I've been in contact with JB Racing who have been super helpful so far.

I'm over this thing at this point, and not sure what to do next.  I can take it to a shop, and they can throw more new parts and may not fix it.  I can pull the clutch / flywheel and send it back to JBR for inspection (they offered). I can part the damn thing out and probably get more than I could whole (I've accumulated some decent parts over the last few years) and move on to something else as a fresh start automotively.  It's not insured so burn it with fire is not an option. I've NEVER had a mechanical problem in all the projects, restorations, engine swaps, that comes close to this level of frustration.

Your pressure plate or disc is boogered.  

The adjustment just pushed the release bearing too far, and didn't have enough travel to fully engage the clutch.  That is why your clutch slipped, and your clue was when you had to force the slave into place.

If you use your finger, you can depress the pedal, and feel when it starts to get resistance that tells you stuff us moving down south.  About an inch at most.is a pretty good sign that you are bled correctly.  You should have a tiny bit of slack to take up the freeway in the pin and assorted mechanical bits, then it should stiffen up pretty quick.

Is there a stop on the clutch pedal at the top?  I suppose if your pushrod were too short, and isn't letting the pedal all the way to the stop, you might not have enough travel.

But you either have a warped flywheel, a bent disc, or a bad diaphragm spring in the pressure plate.

Streetwiseguy said:

Your pressure plate or disc is boogered.  

The adjustment just pushed the release bearing too far, and didn't have enough travel to fully engage the clutch.  That is why your clutch slipped, and your clue was when you had to force the slave into place.

If you use your finger, you can depress the pedal, and feel when it starts to get resistance that tells you stuff us moving down south.  About an inch at most.is a pretty good sign that you are bled correctly.  You should have a tiny bit of slack to take up the freeway in the pin and assorted mechanical bits, then it should stiffen up pretty quick.

Is there a stop on the clutch pedal at the top?  I suppose if your pushrod were too short, and isn't letting the pedal all the way to the stop, you might not have enough travel.

But you either have a warped flywheel, a bent disc, or a bad diaphragm spring in the pressure plate.

Thanks for the reply, and the thoughts.  Prior to this engine swap / clutch fiasco I was running the usual hockey puck stop (located on the firewall on an E36).  I've pulled it out to make sure I could depress the clutch clear to the fire wall for maximum travel.  The clutch pedal actually feels really good (as it should with all new hydraulics). There is very good resistance almost from the very top of the pedal stroke.