'03 540/6 - New JBR Flywheel and UUC Clutch. Clutch Slipping When Cold

[StRaNgEdAyS]

Or the clutch plate is in backwards?

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[JimLev]

Dittos here, but my car is all stock.... No slack at the top might indicate the throw-out is already pushing against the pressure-plate fingers a bit even before the pedal's depressed, causing slippage.

That's what I was thinking too.

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Or the clutch plate is in backwards?

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On a stock setup it would be obvious if the clutch was in backwards don't know about the JB setup. Probably the same with the M5 clutch and pressure plate.

[geargrinder]

Or the clutch plate is in backwards

Hmmm... interesting suggestion!

I don't know what the symptoms are for a disk installed backwards for this car, normally that is opposite - doesn't release - but maybe the failure mode is different?

Great minds and whatnot.

On clutch height... yeah difft brands of PP will be different cuz of the geometries and mechanism differecenss. Can’t compare the SAC OE exactly to others I don’t think... throw will vary a little for sure...

[peter540]

Dittos here, but my car is all stock.... No slack at the top might indicate the throw-out is already pushing against the pressure-plate fingers a bit even before the pedal's depressed, causing slippage. Parts mismatch? Throw-out body too long? Slave push rod too long? Maybe shimming the slave at the bell housing would be a quick fix ....

Interesting idea...

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Hmmm... interesting suggestion!



Great minds and whatnot.

On clutch height... yeah difft brands of PP will be different cuz of the geometries and mechanism differecenss. Can’t compare the SAC OE exactly to others I don’t think... throw will vary a little for sure...

My understanding is that the stack height for my setup is identical to OEM.

[pleiades]

The weird thing about all of this is, your clutch setup was fine for the first 500 miles. That' what confuses me. If the friction disc were installed backwards (it happens...) or there were some other sort of installation snag, I'd think you'd be having problems with the clutch from the get-go.

Earlier I asked about the slipping symptoms and how you confirmed them. That info might help forum peeples to better diagnose what's going on.

I have a theory about winter air condensation on the pressure-plate side of the friction disc, but I'll hold that thought.

Interesting idea...

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My understanding is that the stack height for my setup is identical to OEM.

[geargrinder]

My understanding is that the stack height for my setup is identical to OEM.

Its not so much stack-height that determines the pedal engagement, its the PP mechanics. Stack height determines where the resting fingers sit. For hydraulic clutches actually they are more or less self-adjusting to stack-height differences. The variable is how much finger movement from resting point has to happen before the friction disk is released. That will vary a wee bit with different geometries/designs of PP, as you might imagine.

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If the friction disc were installed backwards (it happens...) or there were some other sort of installation snag, I'd think you'd be having problems with the clutch from the get-go.

True.

[peter540]

The weird thing about all of this is, your clutch setup was fine for the first 500 miles. That' what confuses me. If the friction disc were installed backwards (it happens...) or there were some other sort of installation snag, I'd think you'd be having problems with the clutch from the get-go.

Earlier I asked about the slipping symptoms and how you confirmed them. That info might help forum peeples to better diagnose what's going on.

I have a theory about winter air condensation on the pressure-plate side of the friction disc, but I'll hold that thought.

Sorry -- forgot to answer your questions, I think.

Regarding when the clutch-slip first began, I don't know that it WASN'T slipping from the start. I've been babying the car since the clutch was done to get through the break-in period. I never got on the throttle hard; I maybe applied half the throttle.

Here are the ways in which I detected and verified the clutch was slipping:
* I first noticed the clutch slipping, it was when I accelerated hard from second to third to fourth gear. I noticed the revs going up very quickly, but the car's speed wasn't picking up in parallel.
* I tried the classic clutch-slip test. Around 50 mph, in a high gear (5th or 6th), I mashed the throttle. The revs picked up more than would be typical (and car's speed didn't pick up in parallel).
* When driving up a hill, with the car in third, I applied maybe 3/4 throttle, and again the revs picked up, but the speed didn't, at least not in parallel with the revs.

All of the above clutch tests were when the car was cold. After driving the car for about 40 minutes at highway speeds (mostly), I tried some of these tests again, and there was no clutch slip.

--P

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Its not so much stack-height that determines the pedal engagement, its the PP mechanics. Stack height determines where the resting fingers sit. For hydraulic clutches actually they are more or less self-adjusting to stack-height differences. The variable is how much finger movement from resting point has to happen before the friction disk is released. That will vary a wee bit with different geometries/designs of PP, as you might imagine.

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True.

Good stuff, GG. Thanks!

[geargrinder]

Hmmm. Conditions sound similar to my crap POS don't ever buy a South Bend experience. A little worse perhaps... mine was just on the hard-fast WOT situations (your first bullet point, not so much the 2 or 3...) and mine didn't go away with temperature, mine got worse with increased temperature, i.e. one slipped-shift would almost for sure mean it'd slip the next one unless you let it cool down for a bit.

So, just googling a bit I do see some reports around innerwebz of clutches (not E39 or BMW just general) doing just what you report from very small oil leaks. While I was skeptical about that, cuz i know normally oil contamination just stays and gets worse over time, maybe indeed if its, say, the tiniest little drip over night, it can 'burn off' and then be somewhat OK until next time.

I do know its easy to eff up the main seals, so, indeed maybe that's it.

[peter540]

Hmmm. Conditions sound similar to my crap POS don't ever buy a South Bend experience. A little worse perhaps... mine was just on the hard-fast WOT situations (your first bullet point, not so much the 2 or 3...) and mine didn't go away with temperature, mine got worse with increased temperature, i.e. one slipped-shift would almost for sure mean it'd slip the next one unless you let it cool down for a bit.

So, just googling a bit I do see some reports around innerwebz of clutches (not E39 or BMW just general) doing just what you report from very small oil leaks. While I was skeptical about that, cuz i know normally oil contamination just stays and gets worse over time, maybe indeed if its, say, the tiniest little drip over night, it can 'burn off' and then be somewhat OK until next time.

I do know its easy to eff up the main seals, so, indeed maybe that's it.

Yeah, I did a lot of research on this one, too, and came up with the same sort of info. Small oil leak, too little for oil to end up on the ground or even visible at all. Rob from UUC is pretty confident this is going to be the issue, and while he said the oil can burn off, he also confirmed that we'd definitely need to replace the clutch disc if oil has gotten on it.

Tomorrow will tell us all a lot. What a pain in the arse. But at least it's an excuse to procrastinate on my work to chat with you and the BimmerForums gang...

[peter540]

Update. No leaks, master and slave cylinders fine, no kinks in the lines. But the flywheel and clutch's pressure plate were toasted -- and they could've been worse if I'd not babied the car.

It appears that something -- either the flywheel or the clutch kit -- was not to OEM spec, because the clutch was likely not fully releasing, even when the clutch pedal was fully released/up. We've sent the full assembly to JBR for them to verify the specifications of their flywheel (i.e. that it precisely matches OEM e39 540 specs) and to rebuild it AGAIN.

Regardless of whether their part was faulty or not, UUC has already offered to provide a new clutch kit for free.

The big next step is to get the measurements back from JBR and then to get the flywheel back from them once rebuilt. We'll measure the flywheel once it's back, compare it to measurements from my old, original flywheel, and see where we stand then. That'll be late next week.

Ah well, it's only time and money. And an angry wife (it's not the car's fault -- poor car).

I've been trying to post pics, but for the life of me, I can't get it to work. Not sure what the problem is. Tried from Mozilla and Explorer...

--P

[geargrinder]

I think you meant this peter...

the clutch was likely not fully engaging, even when the clutch pedal was fully released/up.

Looking forward to the JBR report. They seem like a great operation.

[peter540]

I think you meant this peter...



Looking forward to the JBR report. They seem like a great operation.

DOH! Yerp, that's indeed what I meant. Thanks for catching that, GG...

[JimLev]

You had mentioned you had 0 play at the top end of the clutch pedal, bingo. That's why it was slipping.
Did you use a new throw out bearing, was it's length the same as your original one?

[peter540]

You had mentioned you had 0 play at the top end of the clutch pedal, bingo. That's why it was slipping.
Did you use a new throw out bearing, was it's length the same as your original one?

Yes, the UUC kit came with a new throw-out bearing. I believe it's an OEM M5 part. Not sure how its length compared to the original one -- they weren't compared to one another by the shop (I don't think).

[StRaNgEdAyS]

Always, always, always compare the parts before replacing!
It's the first thing you learn when you're learning the trade!
Complacency is a killer

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[peter540]

Always, always, always compare the parts before replacing! It's the first thing you learn when you're learning the trade! Complacency is a killer Sent from my G8141 using Tapatalk

Yep, makes sense. Unfortunately, that's a lesson for next time. Too late this time 'round...

[vasivan89]

I believe everyone mentioned how to find the hydralic leaks. My question is, did you check for coolant leaks? there is a coolant plate of some sort on the m62 on the back. My other input would be that if the clutch disk was backwards, it would not be able to grab like it should and slip all the time. The lines in the material is the wrong way. If you ask me how I know, i have installed a clutch disk backwards on my I6.......very embarrassing and frustrating.

[geargrinder]

My question is, did you check for coolant leaks? there is a coolant plate of some sort on the m62 on the back. My other input would be that if the clutch disk was backwards

Yep. Both of those things were suggested...

[peter540]

Yep. Both of those things were suggested...

Yep. Coolant plate has a new gasket/seal (and is dry), RMS is new (and is dry). Clutch friction disc was, I think, installed in the correct orientation.

Flywheel (and the complete clutch/flywheel stack) should have arrived at JBR today, and they're going to take measurements of their flywheel to ensure its specifications are correct. I'm already sure they are -- this flywheel worked fine in my friend's 540/6, and I had it resurfaced/rebuilt before installing it in my car. That leaves us with the clutch as the likely culprit. We'll see what comes back from JBR in terms of measurements and, ultimately, in terms of the re-rebuilt flywheel, which may show up at my indie's shop on Friday if all goes well.

GG highly recommends the SPEC clutch -- anyone else have experience with that one?

UUC has offered to provide a new clutch kit, even before the results are in regarding the flywheel's specs. That's excellent customer service. I've always had a great experience working with them (Rob, mainly).

--P