Clutch won’t disengage - 530i5 w/ all new components

[computiNATEor]

Huh. Is the TOB the right one? The wear marks on the TOB itself look perfect (concentric, center of the face) but the PP fingers do look worn vs the mileage...

The TOB came with the UUC kit. I can cross reference the part numbers.

[computiNATEor]

I’m definitely replacing the master cylinder at this point, too. I will also be evaluating and replacing the input shaft seal. Maybe the pivot pin, after I measure it.

[Uturn540]

I am going to throw in another thought. It looks like the transmission was not aligned correctly with the engine. Is it possible that a bracket got between the bell housing and engine and caused a slight misalignment. I have seen it happen on other vehicles where the end a wire loom bracket got between the the two. The symptoms seem to indicate as much, leaking front seal, slight gear noise, loose pilot bearing on disassembly, plus the other excessive wear and galling on the pivot pin and TOB guide shaft.

[pleiades]

That's excess wear on the tip of that brass pivot pin (did you grease it?). Makes me wonder what kind of force the aftermarket pressure plate needs, but shouldn't be so much difference compared to stock, right? You need a steel pivot pin! The stock ones by the way are Delrin, which is fairly tough stuff ....

Interesting thought from Uturn540. On these i6s it's easy to get an O2 sensor harness sandwiched between the block and bell housing on re-assembly (because I almost did it!) and I do recall a bracket sitting on the right side that also -can- interfere, but I bet Nate was aware of these bits.

Oh, and I would imagine a correct-size pilot bearing would not fall out on its own, but need a tool of sorts to come out.

[geargrinder]

Also intrigued by Uturns suggesto. But, why wouldn't a shop immediately see the misalign if something else was jammed in there?

[computiNATEor]

I cleaned and greased the crank with anti-seize where the pilot bearing sits pretty well, and I am almost certain that nothing was sandwiched between the engine and transmission. I had the O2 sensor wires secured to the bell housing bolt on the upper right.

I wouldn’t call the pedal effort (when it was working) much higher than stock. It was certainly more work, but not massively so. I drove it in dense city traffic, and I don’t have huge legs.

One of the alignment dowels was missing; the one on the lower right; I will replace it, but I didn’t think it was super critical at the time. The transmission slid into place very nicely.

I would've thought that if I had misaligned the transmission that badly, that I would have struggled much more to get it into place, and I would have had immediate issues.

I will be extra careful to avoid any misalignment problems.

Do you think a steel pivot pin is adviseable, or should I go back to Delrin?

Thank you for your help!

[JimLev]

With one of the alignment pins missing the tranny would not be mounted exactly in line with the engine. There is a little slop in the bolt holes.
The pilot shaft "may" be at a slight angle caused by it not perfectly centered in the bearing.
Not sure if that would cause your problem or it was just one thing in addition to some other issue.
I've got the stock delrin pivot, haven't had any problems with it.

[computiNATEor]

Hmm. Would having it slightly out of alignment cause any other issues I should investigate? Any damage to the clutch or flywheel I should look for?

[computiNATEor]

The Pilot bearing was Febi. I’ll order a BMW one.

So on the shopping list:
pilot bearing
input seal
delrin pivot pin
alignment pin(14.5 mm, I think)
???

[geargrinder]

Yeah, the stock Delrin pins are a never fail part really. I've seen 200k trannies with them still intact. The brass part looks cool and makes you feel better, but - like the brass vs plastic expansion tank bleeder - the plastic one is 100% fine. I have a hard time seeing how the brass one could ever cause a problem tho'... Unless its dimensionally spec'd wrong. All it is is a pivot point... I'm thinking if it wore like that the arm must have been shimmying around a lot due to some other kind of problem. Could the PP have been mis-aligned / off-center? That'd cause a lotta shimmy and crazy vibe when trying to shift under load... (or maybe as already pursuing.. the whole trans was just slightly off...)

[pshovest]

What caused the reddish-brown residue on input shaft splines? Are disk splines rusty? Check that disk slides freely on input shaft. If it doesn't, it will drag on flywheel causing shifting problems. Put a dab of grease on input spline if you didn't previously.

[computiNATEor]

What caused the reddish-brown residue on input shaft splines? Are disk splines rusty? Check that disk slides freely on input shaft. If it doesn't, it will drag on flywheel causing shifting problems. Put a dab of grease on input spline if you didn't previously.

I think that’s a slight bit of surface rust on the input shaft. I applied a light amount of anti seize there.

[computiNATEor]

Yeah, the stock Delrin pins are a never fail part really. I've seen 200k trannies with them still intact. The brass part looks cool and makes you feel better, but - like the brass vs plastic expansion tank bleeder - the plastic one is 100% fine. I have a hard time seeing how the brass one could ever cause a problem tho'... Unless its dimensionally spec'd wrong. All it is is a pivot point... I'm thinking if it wore like that the arm must have been shimmying around a lot due to some other kind of problem. Could the PP have been mis-aligned / off-center? That'd cause a lotta shimmy and crazy vibe when trying to shift under load... (or maybe as already pursuing.. the whole trans was just slightly off...)

I don't think the pressure plate was off-center; as you mentioned, the marks on the throwout bearing were perfectly concentric. It aligns very nicely on the flywheel.

[computiNATEor]

Alrighty, so I placed an order with FCP Euro for some new parts.

2 New dowel pins - I assume I can use my awl to get the old one out
Clutch master cylinder
Pilot bearing
Input shaft seal
Stock delrin pivot pin

With a new hood badge, the damage is ~$150.

[computiNATEor]

Ok, so trans is back in after cleaning and replacing and realigning and stuff. I left the driveshaft and exhaust down, and immediately upon reassembly, the clutch feels normal again, disengaging as it should (I think).

Here’s what I noticed: the clutch pedal feels good, with a smooth friction zone and clear areas at the top and bottom of the travel where it’s fully engaged or fully disengaged.

When the transmission is in neutral, clutch engaged (transmitting power to the input shaft), the output shaft spins as well. I think that’s normal (please tell me if it’s not) because even when the trans is in neutral the output shaft can be spun if the input shaft is rotated. When I disengage the clutch, the output shaft stopped spinning.

Now that I think about it, I should have checked if the output shaft stopped spinning if the trans was in gear.

It was a PITA getting the trans in place. I lined up the clutch and pilot bearing with the somewhat crappy pilot bearing tool as best I could, but it was a three hour ordeal on my back under the car. Boo.

[TerraPhantm]

Output shaft spins in neutral with no load, but there should be low enough torque that you can stop it by hand pretty much.

[computiNATEor]

Right, but if it’s not releasing I wasn’t going to grab it. I’ll see if it spins the tires when I reattach the driveshaft.

[geargrinder]

Yeah - normal. There's enough light friction between the disengaged or 'idling' gears and their shafts that the output shaft will spin.

[pleiades]

New hood badge FTW !!

Seriously tho', what were your conclusions about suspects?

From one of the various DIYs floating around the 'net, I got the idea of making a couple of headless guide dowels from extra-long metric bolts I purchased at a local hardware store (just hacked the heads off and slotted them for easier install/removal after use). That made getting the trans back on a lot easier with a floor jack supporting the trans as I rolled it forward. I believe I also had the front of the engine jacked up a bit so the angle for the re-install was a bit weird, but the trans only weighs 85 lbs. with oil fill and wasn't very tough to move around.

[geargrinder]

From one of the various DIYs floating around the 'net, I got the idea of making a couple of headless guide dowels from extra-long metric bolts I purchased at a local hardware store (just hacked the heads off and slotted them for easier install/removal after use). That made getting the trans back on a lot easier with a floor jack supporting the trans as I rolled it forward.

^^ genius. I hope I remember that next time I'm installing a tranny.

[computiNATEor]

New hood badge FTW !!

Seriously tho', what were your conclusions about suspects?

From one of the various DIYs floating around the 'net, I got the idea of making a couple of headless guide dowels from extra-long metric bolts I purchased at a local hardware store (just hacked the heads off and slotted them for easier install/removal after use). That made getting the trans back on a lot easier with a floor jack supporting the trans as I rolled it forward. I believe I also had the front of the engine jacked up a bit so the angle for the re-install was a bit weird, but the trans only weighs 85 lbs. with oil fill and wasn't very tough to move around.

That is a great idea.

I suspect the trans and engine became slightly out of alignment after a thousand miles of driving because of the missing alignment dowel. That caused the input shaft seal leak, and the clutch to wobble around within the pressure plate, causing it to bind and not release.

I’m also going to replace the clutch master cylinder, simply as a preventative measure.

85 lbs is still pretty heavy, especially when that’s just barely above your head.

[computiNATEor]

I'm getting a lot of noise from the driveline when the clutch is engaged and the car is in high gear (up on jack stands). The noise sounds like extremely loud gear rattle, and it only happens when the engine is at a low RPM. I think it sounds like gear lash in the transmission, as its only in 3rd/4th/5th gears when the engine is idling and there's no load on the driveline. The noise smooths out and goes away at higher RPMs; I think this could be a side effect of the lightweight flywheel.

Here's the video:
https://www.youtube.com/watch?v=hqLCtvUX55E

Does that sound bad? Obviously I don't think that's what it sounds like stock, but does that sound bad for a transmission with a lightweight flywheel?

[JimLev]

Me thinks it will be much better once it's on the ground where there will be a constant load on the drivetrain.
It's still going to rattle because of the LW FW just not as much as it is now up on jack stands.

[computiNATEor]

Ok. I’m going to put it back together. Hopefully I won’t have any more driveline issues for a while.

[geargrinder]

Totally agree w/ Jim, Nate. That's gear rattle, totally normal LWFW life, exacerbated a bit from being up off the ground. Zero-load in-gear obv is a rare condition, it will probably make some noise in neutral when its back on the ground and espec on hot days, but not nearly as bad. .